Air Conditioning Load on Glassed in Lanai

[idlewild]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

[retiredguy123]

You definitely need to add insulation to the ceiling, as much as possible. Attaching ductwork to the existing HVAC system is not a good idea, and it most likely would violate the building code. Some contractors won't even do it. Adding a mini-split system is a good option but, I would first try leaving the doors open to the lanai and see how comfortable it makes the lanai. If you don't have a ceiling fan in the lanai, you should install one to circulate the conditioned air. If the lanai is mostly glass, single pane was not a good idea. You may also encounter condensation on the inside of the glass in the winter. A rule of thumb is that, in a typical house, you lose about two-thirds of energy through the roof, and about one-third through the windows. If the lanai is mostly single pane glass, you are losing even more energy through the windows.

[villagetinker]

I cannot answer your question, but I can provide some advice. We also enclosed our lanai, and went to add AC. I ended up contacting an Engineering company to produce a ~20 page report for the county at a cost of $250. The report gave me the exact size of the AC required, however, I came up with the exact same number when i was researching mini-split systems, several of the sites have a way to fill in the room info to get the size requirements. As to whether this will strain your existing system I have no idea. I am going to send you a PM also.

[Koapaka]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.

[retiredguy123]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.
Good suggestion. But make sure it is large enough. I would be thinking of at least 12,000 BTU and one that heat and cools for a lanai that has single pane glass windows. I don't trust the square footage capacity touted by the companies that make them.

[jimhoward]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.

I thought that because those are portable single units and exhaust out a window they would be prohibited by the deed restrictions. No? My deed says that only central and split unit A/C is permitted.

I took that to mean no portable units. But maybe my interpretation is wrong.

Not that that matters, as it would be inconspicuous.

[retiredguy123]

I thought that because those are portable single units and exhaust out a window they would be prohibited by the deed restrictions. No? My deed says that only central and split unit A/C is permitted.

I took that to mean no portable units. But maybe my interpretation is wrong.

Not that that matters, as it would be inconspicuous.
Window unit air conditioners are prohibited. It is stated in the deed restrictions document. But I called the Community Standards office and asked them if the type that has a round exhaust duct through the window is allowed and they told me that they are allowed.

[asianthree]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.

Durning COVID our HVAC died. Chuck did his best but finally had to put it out of misery. It was August 20, outside temps 87-98 HVAC back ordered 5 weeks.

Week 2 The crew brought a 10,000btu portable for our bedroom, vented through window with a special kit.
Bedroom was 14x18, closing both doors running 24/7. Inside temp of house around 84 at night. Bedroom temp 79

Some nights it was cooler sleeping in the screened lanai with a breeze, than the portable ac in the bedroom. Running portable AC for 3 weeks 1 day, Our Seco billing was $161 more than our July bill with a functioning AC. Bedroom faced south east. It was a long 5 weeks

[Cuervo]

We enclosed our lanai years ago and when we did, we were told if we added AC or Heat it would be considered another room, increasing the tax.
I don't know how your house is structured, but our lanai was built under our roof line, so it was already insulted, plus there was already a fan in place.
Now our lanai faces west, and we have two sets of sliding doors the one we added to enclose the lanai and the one that came with the house leading to the lanai.
When we are not using the space, the double doors add insulation and when we are going to use the space, we just open the sliding doors to the house, and the lanai temperature with the fan quickly becomes the same as the rest of the house.

[retiredguy123]

We enclosed our lanai years ago and when we did, we were told if we added AC or Heat it would be considered another room, increasing the tax.
I don't know how your house is structured, but our lanai was built under our roof line, so it was already insulted, plus there was already a fan in place.
Now our lanai faces west, and we have two sets of sliding doors the one we added to enclose the lanai and the one that came with the house leading to the lanai.
When we are not using the space, the double doors add insulation and when we are going to use the space, we just open the sliding doors to the house, and the lanai temperature with the fan quickly becomes the same as the rest of the house.
What you said in your second sentence is not at all typical. The builder does not install insulation above the ceiling in either the lanai or the garage because these are unconditioned spaces. Most likely, there is no insulation above your lanai ceiling.

[llaran]

We glasses in our lanai, 400 sq ft. BUT IT faces north
The sliding door is open all the time. 2 ceiling fans, we tried the stand alone air for a while and finally put in a split, the problem with it is it drips if we try to get it to cool to match. We also put in the honeycomb shades which do help. Good luck.

[retiredguy123]

We glasses in our lanai, 400 sq ft. BUT IT faces north
The sliding door is open all the time. 2 ceiling fans, we tried the stand alone air for a while and finally put in a split, the problem with it is it drips if we try to get it to cool to match. We also put in the honeycomb shades which do help. Good luck.
It sounds like your condensate drain is clogged or somehow not working properly. You may have a condensate pump that is broken, or the condensate pipe is leaking.

[Annie66]

We expanded our lanai from 180 to 320 sqft. Enclosed the lanai and added a 12K BTU mini split. The AC in the house died at the hottest time of the summer. If it weren't for the min-split, we would have moved to a hotel. With a couple of fans, it supported cooling the central area of the house. The contractor added one of the stand-alone AC units for our bedroom, and we survived the 5-week period to get the AC fixed. If it weren't for the mini split, we would have been in dire straits. Having the completely separate AC unit was a godsend.

[La lamy]

Somewhat unrelated, but 5 weeks for 2 of you to get AC fixed?!!! I hope you looked around for better service. If so, then that timespan is really unsettling. There's always something that can be fixed via readily available parts. Maybe you were convinced by them you had to replace the whole system. Mine has been completely refurbished, one part at a time as they failed.

My glassed in lanai is open to the house and has AC running to it. Even with double paned windows, I usually have to run a fan to feel cool in there. If you want to avoid various extra costs, I would just have fans to cool you off in there and keep it closed off to the house if your wife can stand it!

[mikreb]

Do yourself a favor. Insulate and put in the mini-split you won't regret it. We've tried all the other options, 1. leave the slider open, place a fan in the doorway (still too hot) 2. portable ac (still too hot).

Mini-split, roll down shades and insulation is the way to go. We used Sun Kool, but Munn's is a good option as well.

[ChicagoNative]

Our lanai is 12x15, under the roofline, and faces east, so we get the morning sun. When we glassed it in, we researched cooling options. Of course the HVAC people tried to talk us into a split for $5,000. We asked about tapping into the existing ductwork and were given the song and dance about inadequate insulation and code violation. We insisted that they double check. They ended up doing exactly what we wanted. They tapped off our existing AC, blew extra insulation into the lanai attic, and we now have a comfortable room we use 365 days a year. The total cost for everything was $850. That was pre-Covid about 8 years ago, so things may have changed by now, but you should definitely push back on your HVAC company. You don’t ask, you don’t get.

[treylagger]

We just added a glassed in Cat 5 room to our west-facing lanai - about 220 square feet. Our situation is different though as it's insulated, low E, Argon glass. We raised the floor, removed the existing sliders and insulated the attic. We thought we'd need a mini split (around $6,500) but were able to get by with adding duct work to our existing 2.5 ton AC unit (around $1,800). Our room was finished a couple of days before we left for the summer but we monitor it (and other rooms) with ecobee Smart Sensors - the lanai's temp is the same as the rest of the house.

[Sully2023]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

I enclosed my lani with sliding glass doors and added ceramic tile on the floor. I had insulation blown into the roof area and then tinted the windows. We use the lani during the day and it’s warm, not hot with the ac on and the sliding glass doors to the lani open. I did not install the mini split as to the costs. I’ve not had any issues. It’s nice leaving the living room which is cold to the lani where it’s comfortable. When I enclosed my lani on my Iris it added an extra 300 feet of living space.

[hav7979]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.
I love this idea. We did this and it allows me to move the unit to the garage if I want to cool the garage ro work on golf carts etc.

Also if you open the sliders to the house put the fans in the lani in winter mode so they pull air instead of pushing the air down

[Cuervo]

What you said in your second sentence is not at all typical. The builder does not install insulation above the ceiling in either the lanai or the garage because these are unconditioned spaces. Most likely, there is no insulation above your lanai ceiling.

You might be correct because getting to the to the area above the lanai is inaccessible, but as I stated once we open the doors leading to the lanai and turn on the fan it equalizes to the temperature of the rest of the house.

[Micizel]

We just added a glassed in Cat 5 room to our west-facing lanai - about 220 square feet. Our situation is different though as it's insulated, low E, Argon glass. We raised the floor, removed the existing sliders and insulated the attic. We thought we'd need a mini split (around $6,500) but were able to get by with adding duct work to our existing 2.5 ton AC unit (around $1,800). Our room was finished a couple of days before we left for the summer but we monitor it (and other rooms) with ecobee Smart Sensors - the lanai's temp is the same as the rest of the house.

We are thinking of doing what you just did with raising the floor and removing the sliders inside. We have a mini split. We’re already glassed in with old screen and sliders but want to remove them with solid glass. Can you share who you used for the work?

[rsmurano]

Some misinformation here:
1) you can install a mini split without increasing your property taxes 1 cent.
2) you don’t need a huge report done if you do the lanai correctly: double pane insulated glass, insulation in the attic and good solar reducing blinds.

We built out our 33 x 12’ lanai using double pane egas windows, raised flooring, used the same tile as the house, electricity in the floors and columns, 97% solar blocking shades, and insulated attic. Our sliders give us 16’ of opening into the lanai so leaving the sliders open, we tried living for 1 year without a mini split and it got to uncomfortable out there, we use it every day.
So we put in a Mitsubishi mini split but they call it a dehumidifier so we aren’t taxed. We got the more expensive unit that installed in the ceiling so you don’t see that huge box ($1000 more but worth it). We also use the Cielo thermostat (threw away the remote) so I can program the heating and cooling cycles similar to the ecobee.
Being perfectly comfortable out there in any weather conditions, our electric bill has gone down because the mini split relieves the main hvac system from working overtime to heat/cool the increase of 350 sq feet.

When we got bids from multiple hvac people, they quoted us units that would heat/cool the additional sq ft. I also got bids to use our existing hvac to pipe vents into the lanai. Every vendor said that would overwork the existing unit because all of our hvac units in the villages are under sized so they get rid of the humidity. I looked at zoning with a new hvac system which was more expensive than a mini split.

There are 5 rules that the county has to see if you will pay taxes on your build. For me to get taxed, I would old have to take out my sliders. Since mine open up completely, I’m going to leave them there. I kept 3 boxes of tile so if I decide to remove the sliders, I have tile to replace the tracks.

[cahvillage]

I live in a patio villa and have an enclosed lanai and for 21 years I have left my living room door open so the air can get into the lanai. It gave me another room for living space without getting a splitter and my A/C lasted 21 years with no problems. Chuck Farrell serviced my A/C and there was never a problem.



I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?[/QUOTE]

[jrref]

I would agree that most HVAC systems "may" be a little undersized here in the Villages so they run a little longer to help manage the humidity. But, in reality, HVAC systems that are your main home system usually come in 2, 2.5, 3, 3.5, 4 and 5 ton units so depending on the size of your home and the amount of insulation and the quality of the windows and doors in your lanai you may or may not have extra capacity to extend the existing ducts to the lanai. This is why some people say it works and others, not. The mini-splits many install for their lanai are variable speed inverter systems which are why they are so efficient. They are the best in managing the humidity. You can also get this technology for your home main unit as well.

[bdw08]

We insulated our glassed in lanai and insulated it. Best thing we ever did. Keep the sliders open all the time.

[idlewild]

Thanks for all the helpful information - especially the consideration of having the mini-split as a backup AC (although as we're in a brand new home, I'm hoping we won't ever need that)!

Here's a shocker (well, maybe not considering what I have experience thus far with TV construction):

Our home just under 2000 square feet and our Carrier HVAC is only 3 ton. I'm no HVAC expert - which is why I posted on here in the first place - but I checked with ChatGPT and even without adding another 300 square feet of space to cool in our lanai, our brand new home has a significantly undersized HVAC.

Here's the details:
Our HVAC is a Carrier, Model/Catalog Number: 27SPA636A003.

Using ChatGPT, I learned that "27SPA6" = Series and type of unit (in this case, part of Carrier's Performance series) and the next "36" is the key number to determining size. It indicates the BTU rating and "36" typically refers to 36,000 BTUs. If 12,000 BTUs = 1 ton, 36,000 BTUs = 3 tons. So we have a 3 ton system.

Following up, ChatGPT offered:

"✅ Conclusion:
Your Carrier 3-ton unit (27SPA636A003) should adequately cool a home between 1,200 and 1,500 square feet in ZIP 34762, assuming:
-Standard 8-foot ceilings
-Moderate insulation and window exposure
-No major heat loads (e.g., sunroom or uninsulated attic)

If your home is larger than 1,500 sq ft, this unit may:
-Struggle to maintain target temperatures on hot days
-Run continuously, increasing your electric bill
-Fail to adequately dehumidify

Let me know your exact square footage and house characteristics if you'd like a more tailored answer."

I replied that our square footage is 1967 square feet and we are considering adding a sun room (currently without cooling) which would be ~300 more square feet.


ChatGPT said:
"Thanks — that's very helpful.

📏 Total Space to Potentially Cool:
Existing home: 1,967 sq ft

Planned sunroom: +300 sq ft

Total = ~2,267 sq ft

📍 Location: ZIP 34762 (Okahumpka, FL – hot & humid)
🔍 Analysis:
Using Florida’s typical sizing of 400–500 sq ft per ton, here's the breakdown:

Cooling Load Estimate Tons Needed
2,267 ÷ 500 = ~4.5 tons
2,267 ÷ 450 = ~5 tons (more conservative)

Your current 3-ton unit (Carrier 27SPA636A003) is significantly undersized for this total area, especially with the sunroom added.

🔧 Recommendation:
Option Use Case
5-ton unit Ideal for full-home + sunroom cooling in a Florida climate.
Dual-zone system (e.g. 3-ton + mini-split for sunroom) If replacing the main unit isn’t ideal. Helps avoid oversizing the main system and improves efficiency.
4-ton unit (only if you don’t cool sunroom) Bare minimum for 1,967 sq ft, but borderline in FL. May underperform during peak heat.

✅ Final Answer:
You should upgrade to a 5-ton HVAC system (or add a mini-split to cool the sunroom separately) to adequately and efficiently cool a 2,267 sq ft home in Florida. A 3-ton system will not keep up, especially in July–August, and will wear out faster from overwork.

Let me know if you’d like help comparing Carrier 5-ton systems or mini-split options for the sunroom."

Can any HVAC experts add color here? Are TV 3 ton HVACs undersized for Florida's hot humid climates?

[mtdjed]

Do yourself a favor. Insulate and put in the mini-split you won't regret it. We've tried all the other options, 1. leave the slider open, place a fan in the doorway (still too hot) 2. portable ac (still too hot).

Mini-split, roll down shades and insulation is the way to go. We used Sun Kool, but Munn's is a good option as well.

I agree with this comment. We have a 1900 sq ft home with a 300 sq ft enclosed Lanai with blown insulation above and double pane glass windows facing south. We chose to add mini split. Best investment ever. No worry about weather, open windows. The Lanai has evolved into our living room and all purpose entertainment room year round. $5000 cheap investment to gain 300 square feet of prime living area. We also have 3 fans.

[jrref]

Thanks for all the helpful information - especially the consideration of having the mini-split as a backup AC (although as we're in a brand new home, I'm hoping we won't ever need that)!

Here's a shocker (well, maybe not considering what I have experience thus far with TV construction):

Our home just under 2000 square feet and our Carrier HVAC is only 3 ton. I'm no HVAC expert - which is why I posted on here in the first place - but I checked with ChatGPT and even without adding another 300 square feet of space to cool in our lanai, our brand new home has a significantly undersized HVAC.

Here's the details:
Our HVAC is a Carrier, Model/Catalog Number: 27SPA636A003.

Using ChatGPT, I learned that "27SPA6" = Series and type of unit (in this case, part of Carrier's Performance series) and the next "36" is the key number to determining size. It indicates the BTU rating and "36" typically refers to 36,000 BTUs. If 12,000 BTUs = 1 ton, 36,000 BTUs = 3 tons. So we have a 3 ton system.

Following up, ChatGPT offered:

"✅ Conclusion:
Your Carrier 3-ton unit (27SPA636A003) should adequately cool a home between 1,200 and 1,500 square feet in ZIP 34762, assuming:
-Standard 8-foot ceilings
-Moderate insulation and window exposure
-No major heat loads (e.g., sunroom or uninsulated attic)

If your home is larger than 1,500 sq ft, this unit may:
-Struggle to maintain target temperatures on hot days
-Run continuously, increasing your electric bill
-Fail to adequately dehumidify

Let me know your exact square footage and house characteristics if you'd like a more tailored answer."

I replied that our square footage is 1967 square feet and we are considering adding a sun room (currently without cooling) which would be ~300 more square feet.


ChatGPT said:
"Thanks — that's very helpful.

������ Total Space to Potentially Cool:
Existing home: 1,967 sq ft

Planned sunroom: +300 sq ft

Total = ~2,267 sq ft

������ Location: ZIP 34762 (Okahumpka, FL – hot & humid)
������ Analysis:
Using Florida’s typical sizing of 400–500 sq ft per ton, here's the breakdown:

Cooling Load Estimate Tons Needed
2,267 ÷ 500 = ~4.5 tons
2,267 ÷ 450 = ~5 tons (more conservative)

Your current 3-ton unit (Carrier 27SPA636A003) is significantly undersized for this total area, especially with the sunroom added.

������ Recommendation:
Option Use Case
5-ton unit Ideal for full-home + sunroom cooling in a Florida climate.
Dual-zone system (e.g. 3-ton + mini-split for sunroom) If replacing the main unit isn’t ideal. Helps avoid oversizing the main system and improves efficiency.
4-ton unit (only if you don’t cool sunroom) Bare minimum for 1,967 sq ft, but borderline in FL. May underperform during peak heat.

✅ Final Answer:
You should upgrade to a 5-ton HVAC system (or add a mini-split to cool the sunroom separately) to adequately and efficiently cool a 2,267 sq ft home in Florida. A 3-ton system will not keep up, especially in July–August, and will wear out faster from overwork.

Let me know if you’d like help comparing Carrier 5-ton systems or mini-split options for the sunroom."

Can any HVAC experts add color here? Are TV 3 ton HVACs undersized for Florida's hot humid climates?

From HVAC.com
>>>>>>>>>>>>>>>>>>>>
How many BTU per square foot?
A BTU, or British Thermal Unit, is a rating that measures the energy your AC uses in one hour to remove heat from your indoor air. The BTU of your HVAC system should be based on the square footage of your home, insulation quality, climate zone, and ductwork.

Generally, you need 20 BTU for every square foot of space in your home. The chart below can guide your BTU choice:

Home Square Footage BTU (British Thermal Unit) Tonnage
600 – 1,000 18,000 1.5
1,000 – 1,300 24,000 2
1,300 – 1,600 30,000 2.5
1,600 – 1,900 36,000 3
1,900 – 2,200 42,000 3.5
2,200 – 2,600 48,000 4
2,600 – 3,200 60,000 5
The larger your home, the higher BTU you’ll need to support your comfort. One of the most accurate ways to measure the right size AC for your home is with a Manual J calculation.

So you AC is sized correctly.

[idlewild]

Generally, you need 20 BTU for every square foot of space in your home. The chart below can guide your BTU choice:

Home Square Footage BTU (British Thermal Unit) Tonnage
600 – 1,000 18,000 1.5
1,000 – 1,300 24,000 2
1,300 – 1,600 30,000 2.5
1,600 – 1,900 36,000 3
1,900 – 2,200 42,000 3.5
2,200 – 2,600 48,000 4
2,600 – 3,200 60,000 5
The larger your home, the higher BTU you’ll need to support your comfort. One of the most accurate ways to measure the right size AC for your home is with a Manual J calculation.

So you AC is sized correctly.

We're at 1967 sq feet which is 3.5 tons according to your chart. It would likely strain if we added another 300 square feet (the lanai space) for a total of 2267 which is 4 tons according to this chart.

That stated, I went to the site you referenced and it seems the year of construction (2025) is weighs more heavily than our post code (34762) so it does indeed recommend a 3 ton (https://www.hvac.com/tools/hvac-load-calculator/results/?squareFeet=2000&yearBuilt=2025&zipCode=34762).

[treylagger]

We are thinking of doing what you just did with raising the floor and removing the sliders inside. We have a mini split. We’re already glassed in with old screen and sliders but want to remove them with solid glass. Can you share who you used for the work?

We used Custom Windows & Exterior Design for the entire project except for the tile floors - we hired Roberto’s to do that. Custom Windows has their own crew for doing the cement floor and finishing work. Everything else they sub out - insulation, electric, etc. We also hired Sunshine to do the AC duct work - that and the tile floors were all we were responsible for.

[patfla06]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

We put in insulation, Mitsubishi mini split and the doors are tinted.
Have an Eastern exposure with only sun hitting it until 11 am.
A mini split is essential IMHO. You will use the lanai every day with a mini split.

[talonip]

Easy solution for a fraction of the price. Go to Amazon and buy one of the BLACK+DECKER 8,000 BTU Portable Air Conditioner for Rooms up to 350 Sq. with Remote Control, White
Visit the BLACK+DECKER Store
4.1 4.1 out of 5 stars 49,772 ratings
for less than $400. Problem solved when extra cooling is needed.

Tried that. Noisy and won’t work.

[talonip]

We have had two houses and enclosed both. Single pane. Don’t get sucked into double pain unless you have a west facing lanai with unobstructed view. We put insulation in the first house with 280 sq ft lanai. In second home we did not with 500 sq ft. Hardly noticed a difference. We put two mini splits in second lanai. We love it. One thing that is nice the villages weather and temp from late Oct to middle of April is great. Mini splits use was minimal. We use our lanai all the time. It’s well worth the cost to enclose and pit mini splits in. Ask contractor to put in the flush ceiling mounted mini.

[Annie66]

Somewhat unrelated, but 5 weeks for 2 of you to get AC fixed?!!! I hope you looked around for better service. If so, then that timespan is really unsettling. There's always something that can be fixed via readily available parts. Maybe you were convinced by them you had to replace the whole system. Mine has been completely refurbished, one part at a time as they failed.

My glassed in lanai is open to the house and has AC running to it. Even with double paned windows, I usually have to run a fan to feel cool in there. If you want to avoid various extra costs, I would just have fans to cool you off in there and keep it closed off to the house if your wife can stand it!

I understand your concern. Unfortunately, our breakdown happened at the height of Covid. Parts were scarce. No one had the parts in the area, so we waited.

[skippy05]

It might be less expensive and less trouble to just replace the wife?

[Ptmcbriz]

Being south facing you are also going to need to add rolling shades on all the windows that help block the sun to help keep it cooler. Everyone I know has the split units to keep it cool. The last thing you want to do is put a strain on your house system.

[Nana2Teddy]

We have had two houses and enclosed both. Single pane. Don’t get sucked into double pain unless you have a west facing lanai with unobstructed view. We put insulation in the first house with 280 sq ft lanai. In second home we did not with 500 sq ft. Hardly noticed a difference. We put two mini splits in second lanai. We love it. One thing that is nice the villages weather and temp from late Oct to middle of April is great. Mini splits use was minimal. We use our lanai all the time. It’s well worth the cost to enclose and pit mini splits in. Ask contractor to put in the flush ceiling mounted mini.

This is our situation. We chose single pane for east facing 400sf lanai because it was $15K vs $29K, and Custom Windows told us single pane was sufficient. We had ceiling insulated and two ceiling mounted minisplits installed by Kalos, and they work great except in the dead of summer when the morning sun heats up the room quickly forcing the minisplits to work extra hard all day trying to cool it back down to 75. So, we have 100% solar blocking interior motorized shades being installed next week to block morning sun until 11-12, then will raise them for rest of the day and night. The shades will block the sun from fading everything in our lanai too. This is a private fenced-in yard, no view, so we don’t mind shades being down in morning for 2-3 months annually. We do keep our sliders to the lanai open all day.

[Nana2Teddy]

It might be less expensive and less trouble to just replace the wife?
Hmm… I thought my hubby wasn’t on TOTV. 😂

[JRcorvette]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

You definitely should insulate the ceiling and it may be required. Double pane glass does not help all that much. Better to spend the money on some sun screen shades to use when needed. I would suggest try leaving the doors open during the daytime and close when you go to bed (mostly for security). See how your energy bill changes. An extra 300sf is not that much. The cost of adding a mini split AC is between $6000 & $7500. Do the math that will cover many years of a slightly higher AC bill.

[retiredguy123]

Do yourself a favor. Insulate and put in the mini-split you won't regret it. We've tried all the other options, 1. leave the slider open, place a fan in the doorway (still too hot) 2. portable ac (still too hot).

Mini-split, roll down shades and insulation is the way to go. We used Sun Kool, but Munn's is a good option as well.
Yes, and any attempt to add any conditioned air to a lanai without insulating the ceiling is like trying to fill a bucket with water when it has a hole in the bottom.

[C. C. Rider]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

Here is a portable unit that works well. It runs on regular household (110 volt) current. It has a small drain line for the condensate which you could run to the outside or into a bucket.

It also has an exhaust hose (about 6" diameter) that needs to be vented to the outside either through a permanent installation or through the supplied window opening kit. I bought one last year for occasional use in my insulated garage. It works well.

Amazon.com (https://www.amazon.com/LifeMaster-Portable-Conditioners-Conditioner-Installation/dp/B0D3VMC71V/ref=sr_1_3?crid=20XGI5BMJJE34&dib=eyJ2IjoiMSJ9.warBhiazgJ0hIebMwHjYHnxOU7jkGUJ_L WXlDk4XhO7c38vd3eUZWNnCP2iDJqZQalncO2UXQ5YN2yWXlGN 09SzdTA8F7JFhOZ21HdKu8Uu4cQVfjp7I139RCt0eqyeWOV11z YoTZ6ZaEfzK6IExTLYWbrD9QGPIXkXmGxzddy666rfuOkODpTM IzbQtgZHwW2OE7MWNaty4u6W6YDi2JEKEng-NUxpKdHm8sdMDlCxz5CWHgIMdpGR8YjS1JzobNt9gPwMS11jWo XbbZ5run6WyOLE7aL2Z196jMcn0zFA.1yzRnmGZJ25X1UTyawt 6gWmyOiKIceJM1PZ5GeK6GFM&dib_tag=se&keywords=portable%2Bair%2Bconditioners%2Blife%2Bma ster&qid=1749396559&s=home-garden&sprefix=portable%2Bair%2Bconditioners%2Blife%2Bmas ter%2Cgarden%2C110&sr=1-3&th=1)

[Accidental1]

We recently had our ~300 sq ft. south-facing lanai enclosed with single pain / non-insulated glass on our ~1900 sq ft home. The wife wants "open living" (i.e. to keep the doors to the lanai open) and thought we could do it after we blew insultation into the lanai.

I'm concerned that not only are the new windows and door not double-paned (i.e. no insultation) but also the added space will strain our AC unit In fact, when I saw the price of a mini-split I figured we might be able to extend the existing ductwork into the lanai after insulating, but I was told from multiple contractors that this would strain the AC and is not to code.

Questions: even if we blew insultation, how much cool air would we be bleeding from the single-pain glass? With this leakage and new 300 sq feet to cool, how much of a load/strain would leaving the doors to the lanai open place on our AC unit and is that comparable to having the ducts directly into it?

My idea of "open living" is not keeping the doors open, but rather using the lanai occasionally with the doors open (i.e. air conditioning from the home) but mostly using it later at night with windows open for a breeze to naturally cool it, but I supposed we're going to have to minimally both blow insulation and get a mini-split if my wife wants to keep the doors open all the time, correct?

We're West facing and enclosed our lanai with dual pane sliders. We tried it for a year without insulating the ceiling or a mini split. The home AC didn't come close to being able to cool the lanai. We've since added motorized shades, a mini spit and insulation. Good luck.

[idlewild]

It might be less expensive and less trouble to just replace the wife?

:agree:

[Teed_Off]

This probably depends on how you and the wife define comfortable. We have a Lantana model with a ~300sf south facing lanai with 12’ of east and west sliders, all full height. The windows are double pane, low-e glass. The south windows are partially shaded by the overhang and pine trees. The east windows are fully exposed to a patio and there’s a hedge along the west windows. We have indoor shades on the east and west only. The ceiling is insulated and there are two ceiling fans. The sliders to the house are always open so that the lanai is passively cooled and heated from the house system.

In the summer we keep the house at 79 degrees F and 68 in the winter. In the spring and fall the lanai sliders and nearly all other house windows are open with the a/c system turned off.

I have found that the temperature in the lanai is about the same as the house during the summer, maybe 1 or 2 degrees warmer late in the day, and it’s a few degrees cooler in the winter, particularly in the morning.

Bottom line for us, with this arrangement for the last 7 years, is that we are comfortable and don’t need supplemental cooling or heating.

[PatriciaFaheySimms]

I have a south facing lanai like yours and I installed UV film on the glass. I also had it installed on the west facing windows of the house. It’s about 10° cooler in the lanai. I prefer the UV film to shades that would block the view of the beautiful large live oaks. If the view is the neighbors roof, then I would get UV blocking shades.

[retiredguy123]

We have had two houses and enclosed both. Single pane. Don’t get sucked into double pain unless you have a west facing lanai with unobstructed view. We put insulation in the first house with 280 sq ft lanai. In second home we did not with 500 sq ft. Hardly noticed a difference. We put two mini splits in second lanai. We love it. One thing that is nice the villages weather and temp from late Oct to middle of April is great. Mini splits use was minimal. We use our lanai all the time. It’s well worth the cost to enclose and pit mini splits in. Ask contractor to put in the flush ceiling mounted mini.
Don't get sucked into double pane??? If you have a room that is being heated and cooled, why would you use single pane glass windows? Double pane glass has been the minimum standard for all windows in housing construction for longer than 30 years. Nobody installs single pane windows in a house that is heated and cooled.

[jrref]

Don't get sucked into double pane??? If you have a room that is being heated and cooled, why would you use single pane glass windows? Double pane glass has been the minimum standard for all windows in housing construction for longer than 30 years. Nobody installs single pane windows in a house that is heated and cooled.

Right, so, most people look for the lowest cost without really understanding. When the HVAC person comes to do the load calculation and inputs single pane windows, the load will be a lot higher than if they were double pane windows. So, the customer thinks they are saving money by getting single pane windows but is spending more for the larger capacity AC equipment and the cost to run it for the life of the system.

[Flyers999]

This is our situation. We chose single pane for east facing 400sf lanai because it was $15K vs $29K, and Custom Windows told us single pane was sufficient. We had ceiling insulated and two ceiling mounted minisplits installed by Kalos, and they work great except in the dead of summer when the morning sun heats up the room quickly forcing the minisplits to work extra hard all day trying to cool it back down to 75. So, we have 100% solar blocking interior motorized shades being installed next week to block morning sun until 11-12, then will raise them for rest of the day and night. The shades will block the sun from fading everything in our lanai too. This is a private fenced-in yard, no view, so we don’t mind shades being down in morning for 2-3 months annually. We do keep our sliders to the lanai open all day.

Mine is western facing and we put the motorized shade down after 2pm. The opposite of what you do. We did not enclose the lanai with glass like you have done.
Why didn't you just put up curtains or vertical blinds instead of the motorized shade? Motorized shades are not cheap and don't last forever.

[C. C. Rider]

Don't get sucked into double pane??? If you have a room that is being heated and cooled, why would you use single pane glass windows? Double pane glass has been the minimum standard for all windows in housing construction for longer than 30 years. Nobody installs single pane windows in a house that is heated and cooled.

I disagree. The window insulation requirement is based on temperature difference between the outside temperature and the desired inside temperature. Up north, it may be 0 degrees outside and 70 degrees inside. That's a temperature difference of 70 degrees. You definitely need double-pane windows for a 70 degree temperature difference.

Down here in Florida, the "winter" is so mild as to make thermopane windows unnecessary. As for the summer cooling, it seldom gets hotter than about 95 degrees, and that's only for a few hours per day in the hottest part of the summer. Your temperature difference then is only about 17 degrees if you keep the inside at 78 degrees.

Many people would argue that thermopane windows are unnecessary for a mere 17 degrees temperature difference. My 2,400 square foot house has single pane windows, including my enclosed lanai, and my heating and cooling bills are very modest even during the hottest part of the summer.

In short, Leesburg is not Minneapolis. :)

.

[retiredguy123]

I disagree. The window insulation requirement is based on temperature difference between the outside temperature and the desired inside temperature. Up north, it may be 0 degrees outside and 70 degrees inside. That's a temperature difference of 70 degrees. You definitely need double-pane windows for a 70 degree temperature difference.

Down here in Florida, the "winter" is so mild as to make thermopane windows unnecessary. As for the summer cooling, it seldom gets hotter than about 95 degrees, and that's only for a few hours per day in the hottest part of the summer. Your temperature difference then is only about 17 degrees if you keep the inside at 78 degrees.

Many people would argue that thermopane windows are unnecessary for a mere 17 degrees temperature difference. My 2,400 square foot house has single pane windows, including my enclosed lanai, and my heating and cooling bills are very modest even during the hottest part of the summer.

In short, Leesburg is not Minneapolis. :)

.
Single pane glass windows in houses do not comply with the Florida building code. This has been a code requirement for more than 10 years.

[jrref]

I disagree. The window insulation requirement is based on temperature difference between the outside temperature and the desired inside temperature. Up north, it may be 0 degrees outside and 70 degrees inside. That's a temperature difference of 70 degrees. You definitely need double-pane windows for a 70 degree temperature difference.

Down here in Florida, the "winter" is so mild as to make thermopane windows unnecessary. As for the summer cooling, it seldom gets hotter than about 95 degrees, and that's only for a few hours per day in the hottest part of the summer. Your temperature difference then is only about 17 degrees if you keep the inside at 78 degrees.

Many people would argue that thermopane windows are unnecessary for a mere 17 degrees temperature difference. My 2,400 square foot house has single pane windows, including my enclosed lanai, and my heating and cooling bills are very modest even during the hottest part of the summer.

In short, Leesburg is not Minneapolis. :)

.

I'm not disputing what you have said but regardless, single pane windows will increase the heat load on the system and as a result you may need to purchase a larger system or if not, it will definetly be working harder to cool. Then end result is you will be paying more running it for the service life of the system.

[C. C. Rider]

I'm not disputing what you have said but regardless, single pane windows will increase the heat load on the system and as a result you may need to purchase a larger system or if not, it will definetly be working harder to cool. Then end result is you will be paying more running it for the service life of the system.

I'm not saying that single pane windows are as energy efficient as double pane windows. I'm simply saying that the slight extra cost for heating and cooling a house with single pane windows to reasonable temperatures here in central Florida doesn't justify the significantly additional cost of the double-pane windows all over the house.

My all-electric house with my wife and I living here year-round averages using 35 KwH per day or about 1,050 KwH per month. My average monthly bill with SECO is about $150 and I have NO gas bill. I can't complain at all about those costs.

EDIT TO ADD: According to this link Florida Building Code • Requirements • Windows | FHIA Remodeling Blog (https://fhiaremodeling.com/blog/florida-window-code-requirements/), it doesn't appear that double pane windows are required in this area.

.

[jrref]

I'm not saying that single pane windows are as energy efficient as double pane windows. I'm simply saying that the slight extra cost for heating and cooling a house with single pane windows to reasonable temperatures here in central Florida doesn't justify the significantly additional cost of the double-pane windows all over the house.

My all-electric house with my wife and I living here year-round averages using 35 KwH per day or about 1,050 KwH per month. My average monthly bill with SECO is about $150 and I have NO gas bill. I can't complain at all about those costs.

EDIT TO ADD: According to this link Florida Building Code • Requirements • Windows | FHIA Remodeling Blog (https://fhiaremodeling.com/blog/florida-window-code-requirements/), it doesn't appear that double pane windows are required in this area.

.

I'm not so sure. I would have to do the calculations but my guess is with single pane windows you will probably be paying way more in energy costs "over the life" of the system than the initial cost of the double pane windows.

[retiredguy123]

I'm not saying that single pane windows are as energy efficient as double pane windows. I'm simply saying that the slight extra cost for heating and cooling a house with single pane windows to reasonable temperatures here in central Florida doesn't justify the significantly additional cost of the double-pane windows all over the house.

My all-electric house with my wife and I living here year-round averages using 35 KwH per day or about 1,050 KwH per month. My average monthly bill with SECO is about $150 and I have NO gas bill. I can't complain at all about those costs.

EDIT TO ADD: According to this link Florida Building Code • Requirements • Windows | FHIA Remodeling Blog (https://fhiaremodeling.com/blog/florida-window-code-requirements/), it doesn't appear that double pane windows are required in this area.

.
I didn't fully understand the link you provided, but it looks like it goes back to 2002. Apparently, the code was updated in 2015. Please read the attached references:

Are single pane windows legal in Florida?
Thousands of Florida homes have been constructed with aluminum single-pane windows, which under the updated Florida Building Code released in July, are not permissible in most cases in new construction and window replacement projects.Dec 12, 2015
Your browser is not supported | dailycommercial.com (https://www.dailycommercial.com)
Understanding replacement window regulations - Leesburg Daily Commercial

From AI:
Single-Pane Windows:
Many older homes in Florida have single-pane windows, which are not considered compliant with current code regulations.

[C. C. Rider]

None of the referenced links that I read compared the cost difference in a warm climate such as Florida. So, using my all electric home as an example, let's do some "back of the envelope" figuring.

Let's say that a house with ALL double-pane windows costs an extra $6,000 here in Florida. Now, again using my heating/cooling costs as an example, let's say that my monthly electric bill in my ALL ELECTRIC home was reduced about $30 per month if I had all double-pane windows.

OK, so $30 per month equals $360 per year. At that rate, it would take 16.7 years just to break even. I don't know about you, but if someone offered me $6,000 CASH TODAY or $30 per month for the next 16.7 years, I'm going to take the $6,000 CASH TODAY!

Further, if you studied economics and the "time value of money", you'll know that dollars "saved" at some point in the future aren't worth nearly as much as dollars saved TODAY. So, if we factored that into our "break even" point above, it would take MUCH longer to break even than 16.7 years.

.

[retiredguy123]

None of the referenced links that I read compared the cost difference in a warm climate such as Florida. So, using my all electric home as an example, let's do some "back of the envelope" figuring.

Let's say that a house with ALL double-pane windows costs an extra $6,000 here in Florida. Now, again using my heating/cooling costs as an example, let's say that my monthly electric bill in my ALL ELECTRIC home was reduced about $30 per month if I had all double-pane windows.

OK, so $30 per month equals $360 per year. At that rate, it would take 16.7 years just to break even. I don't know about you, but if someone offered me $6,000 CASH TODAY or $30 per month for the next 16.7 years, I'm going to take the $6,000 CASH TODAY!

Further, if you studied economics and the "time value of money", you'll know that dollars "saved" at some point in the future aren't worth nearly as much as dollars saved TODAY. So, if we factored that into our "break even" point above, it would take MUCH longer to break even than 16.7 years.

.
Your $6,000 estimate seems high to me, but I would just point out that the double pane windows will offer better noise control, less chance for condensation issues, more even heating and cooling, building code compliance, and most important, a higher resale value. I would not even consider buying a house that had single pane windows.

[thelegges]

I'm not saying that single pane windows are as energy efficient as double pane windows. I'm simply saying that the slight extra cost for heating and cooling a house with single pane windows to reasonable temperatures here in central Florida doesn't justify the significantly additional cost of the double-pane windows all over the house.

My all-electric house with my wife and I living here year-round averages using 35 KwH per day or about 1,050 KwH per month. My average monthly bill with SECO is about $150 and I have NO gas bill. I can't complain at all about those costs.

EDIT TO ADD: According to this link Florida Building Code • Requirements • Windows | FHIA Remodeling Blog (https://fhiaremodeling.com/blog/florida-window-code-requirements/), it doesn't appear that double pane windows are required in this area.

.

Our 2,872sf house with a pool KwH daily usage in summer months is 28-31KwH. Windows are double pane house is navy blue, which does draw more heat than our yellow house

[C. C. Rider]

Our 2,872sf house with a pool KwH daily usage in summer months is 28-31KwH. Windows are double pane house is navy blue, which does draw more heat than our yellow house

Is that house "all electric" like mine? Also, are you heating the pool?

.

[mtdjed]

You definitely should insulate the ceiling and it may be required. Double pane glass does not help all that much. Better to spend the money on some sun screen shades to use when needed. I would suggest try leaving the doors open during the daytime and close when you go to bed (mostly for security). See how your energy bill changes. An extra 300sf is not that much. The cost of adding a mini split AC is between $6000 & $7500. Do the math that will cover many years of a slightly higher AC bill.

Disagree with your statement that double pane glass does not help that much. Agree that shades should be added. The shades can minimize the direct sun radiant heat. Single layer of glass windows will act like a heater during the summer and a cooler during colder weather.

Doing it cheap is a choice that you would likely regret. Our 300 sq ft addition was done with insulation, Double pane windows, shades, and Mini split. It is our main living area year-round. No restrictions. The room is efficient all year round with no need to think about lanai doors open or closed.

[RICH1]

install MITSUBISHI Split unit in your patio... It will make everyone happy.. You will be glad you did.. Best money I ever spent

[jrref]

None of the referenced links that I read compared the cost difference in a warm climate such as Florida. So, using my all electric home as an example, let's do some "back of the envelope" figuring.

Let's say that a house with ALL double-pane windows costs an extra $6,000 here in Florida. Now, again using my heating/cooling costs as an example, let's say that my monthly electric bill in my ALL ELECTRIC home was reduced about $30 per month if I had all double-pane windows.

OK, so $30 per month equals $360 per year. At that rate, it would take 16.7 years just to break even. I don't know about you, but if someone offered me $6,000 CASH TODAY or $30 per month for the next 16.7 years, I'm going to take the $6,000 CASH TODAY!

Further, if you studied economics and the "time value of money", you'll know that dollars "saved" at some point in the future aren't worth nearly as much as dollars saved TODAY. So, if we factored that into our "break even" point above, it would take MUCH longer to break even than 16.7 years.

.

First, I'm confused by your response. The OP was talking about the windows in their Lanai not the whole house. I don't believe the price difference between single and double pane windows in a closed in lanai is as much as you are stating. You also have to realize the heat gain is significant because the lanai is a glass enclosed room. Way different that a window in an insulated wall.

But If you are not going to spend the extra money on double pane windows then why even spend money insulating the lanai ceiling? According to your calculations it's not worth it.

[thelegges]

Is that house "all electric" like mine? Also, are you heating the pool?

.

Pool gets full sun summers all day, instead of heat we run chiller to keep temp at 84-86 degrees. We have a gas tankless water heater, gas dryer and range. The house is a premier so the entire interior is 10 foot ceilings. We are considering adding a mini split to the garage because it’s south facing this winter.
If we do heat the pool in the January and February it doesn’t cost much because of full sun, keeping water warmer, I prefer swimming at 80° water temp during the winter. We do use liquid pool cover, so even on a very cold night our temp loss is usually 2-3 degrees

[Laurawilcox]

If you are considering installing after market tinting film, I would suggest checking the warranty on your double pane windows. In most cases (depending on manufacturer) the warranty is voided, this is because the darker films can attract excess heat to the glass causing an increase in pressure in between the 2 panes making the window more prone to seal failures.

Most new glass can be ordered with the option of tint that is actually part of the glass composition, this allows you to retain manufacturer warranty.

I am in the warranty department at Custom Windows and Exterior Design and help our homeowners with tinting questions regularly.