[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]

Originally Posted by 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?

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]

Originally Posted by 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.

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]

Originally Posted by retiredguy123

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]

Originally Posted by 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.

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]

Originally Posted by 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.

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]

Originally Posted by 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?

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]

Originally Posted by jrref

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.

[treylagger]

Originally Posted by Micizel

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.