Variable Speed Inverter HVAC Redux
 

I had a Carrier Infinity Greenspeed HVAC sytem installed yesterday by Sunshine HVAC. As discussed in another thread last week, these systems should save you about 35% on your energy bill, provide exceptional temperature and humidity control, provide superior air filtration and are super quiet. Also, the heat pump will provide heat without the need for Auxillary heat strips all the way down to -13 degrees. So, while our existing systems are struggling at temps below 40 degrees, this system will be very efficient and be cheaper to run even when we need heat. This system uses the same heat pump technology as the mini splits everyone is installing to cool their lanai and garages.

I have a 4 ton system and after watching these techs work, knowing what I know from working with a HVAC contrator while working my way through college, I started to realize the difference in price between contractors for the same exact system may be related to their installation process. In my case eventhough I replaced my existing single stage 4 ton system with a new 4 ton system, the Infinity airhandler is 21 vs 24 inches so the lower plenum that the air handler sits on had to be replaced along with the plywood base. In addition, they replaced everything existing with new which included a new line set, condensate drain, all new duct work in the HVAC closet. They even crawled under the air handler platform once they opened it up to insulate the "cold" side of the line set all the way to where it goes to the outside wall and spray foamed it at that point. I couldn't believe what I was seeing. Normally, they pull a new lineset and the pipe insulation goes on as best it can. Here they made sure there was no way that line was going to sweat and leak condensation and over time causing mold. Also, on the duct connections they used mastic along with the typical metal tape to seal the new to the old joints. Everything was caulked and painted as needed. In addition, outside by the condensor they installed a device which monitors the electric voiltage so if the voltage goes too high or too low during a power event, it disconnects the system. This "box" also includes a power surge protector.

Sunshine also has a person come to your home and do a follow-up to make sure everything was done to your satisfaction, to explain how to use the thermostat and to set up the App on your phones. I feel this is a nice touch.

All I can say is these techs did everything "by the book" based on my knowledge and it took about 7 1/2 hours to do the job. As mentioned, I can see how some HVAC contractors possibly could skip a lot of these steps and charge a cheaper price. And be prepared for the estimator to say "oh you don't need to change that" LOL. That said, when you get estimates, make sure you are comparing the same equipment and find out what they are replacing in order to do a valid comparison. My guess is given everything the same, there shouldn't be that much difference in price between reputable HVAC contractors here in the Villages.

One final comment. For those who say they are going to stick with the simple single stage units because they can get a replacement in a day, I asked and these new inverter systems are stocked like the basic units becasue they are installing many of them now and if they don't have it, there are two Carrier distributers close to the Villages where they can get a replacement in a day. They also said, sometimes the basic units may be out of stock and you need to wait so, these days the type of equipment shouldn't be a concern when thinking about a replacement scenaro in the middle of the summer.

Hope this helps those considering or needing a new system.

Very interesting - congrats on the upgrade!

How much temperature drop do you see between input and output?

It's supposed to be around 20 degrees. I have to measure it.

Just measured it, 20 degrees deltaT

The condenser from the factory has enough refrigerant charge for a 15 ft long line set. In my case, my line set was a little under 15 ft so all they did was evacuate the system to a very high vaccume then released the freon into the system. The system came up after a whole bunch of diagnostics and after about a half hour, all the pressures stablized. No tweaks needed. I checked everything today using the pressures and other readings available via the thermostat and it all looks good. I believe if the pressures, subcooling, superheat, etc, are not right you will get an error notification on the thermostat.

The system is pretty amazing. And I got the 10 years labor and parts so nothing to worry about if anything fails during that time. In fact, the unit I got if the compressor or any of the refrigerant parts in the condenser fail during the first 10 years, Carrier gives you a whole new condenser vs repairing.

Just some observations with my new system.
1) Super quiet
2) Exceptional humidity control. The system will go into a dehumidify cycle where the AC is on very low where you can't detect it to dehumidify. Very cool.
3) Even on 100%, "full blast", the new system draws less than half the amperage of the old system.
4) Superior room temperature equalization with only one zone.

Now, let's see if all this wonderful technology will last more then 5-8 years
before another latest and greatest unit comes along.

I won't be here long enough to spend that much. Still using original 18 yr. old. Can't hear it even when hearing aids are in place.

You failed to mention the COST!

We installed an Airtemp central AC 4 years ago with a single stage scroll compressor heat pump and backup heat strips. It uses about half the energy of the Rheem it replaced. We hardly use any heat in the Winter so the heat strip aren't a factor. The scroll compressor is very efficient. The system is much less electronic and complicated.

After spending time in NEW TV built homes over the last several months, there is a HUGE difference in comfort between the single speed & variable speed systems.
Our village is all new. 5 of our neighbors went single speed basic, while I went with the mid level variable speed system. They all comment how our outdoor is HUGE compared to theirs.
After spending time in our 6 neighborhood homes, our variable speed system provides a far more comfortable environment to be in.
That is, you don’t get froze out every time the system turns on.
Right on que, just last night we were all in one of the neighbors house socializing at the dining table. When the system kicked on, it got overly cold real quick. To the point where several women were asking for blankets. Yes the thermostat was set to a reasonable temperature. That’s just how those single speed systems work. Bigger temperature swings each direction, and consequently poorer humidity control because of that.
When we are all in our variable speed system house, no one says a thing. Everyone, women especially, are just comfortable. It just plain works more efficiently. More stable temperature, better humidity control, all due to the VARIABLE speeds the system uses.
When we stayed a few days in a lifestyle visit single speed home for our design days, I couldn’t stand the uncomfortable temperature/humidity swings. Which spurred me to inquire about their available HVAC systems on new construction. There was no way I was installing their base system, or I would not be living here.
Yes there was a modest 5K price increase for our mid level system. Some of the best money spent on our build.
I put a big value on being comfortable. And an even bigger value on keeping my wife happy and comfortable. And therefore making my life better, no nagging “it’s to cold, it’s to humid”. That’s some serious value for the extra money spent.

A typical single stage Heat pump system will cost about $8k-$9K. Maybe you can find a cheap system for a little less. Right now, with the $2,000 Federal tax credit and rebates from Carrier, Sunshine and if you have Duke energy there is another $1K rebate, the $17K Carrier Infinity Greenspeed system costed me $13K net and that includes 10 year parts and labor. With this system you should save about 35% on energy costs so the extra couple thousand dollars spent can be recouped in about 5 years or so.

Timing is everything and I don't know how long the Federal tax credits will remain in-place with the current administration.

The technology of variable speed units has been out for ten years. Where have you been? Do you still use leaded gas in your 1949 Chevrolet?

Right and Carrier and others have refined the technology to meet the new efficiency guidelines. Carrier has had the Infinity line for the last 15 years recently they have Infinity Greenspeed.

We have always been happy with Sunshine. They once came at 1 AM to fix out AC.

I think Sunshine and Munns are probably the two best large HVAC companies here in the Villages. There are other smaller family owned companies which are good as well.

When I purchased my Carrier Infinity Greenspeed system, since I knew the basic variable speed inverter technology was around for 10 years or more, this is the same technology in the mini splits everyone is buying these days, I wanted a company that was installing a lot of these systems so I knew I had a good chance of getting a great installation and competant service over the life of the product. Also, from experience, it pays to spend a little more with a company who is a major dealer in the brand of system you intend to purchase.

Many rate their favorite company on how fast they came at their time of need and that's totally fine but beyond price, the quality of the installation is probably the most important aspect since it will be a major factor in the longevity of your system.

I just discovered as of 1/1/2025 if you want a Carrier Heatpump or single AC system, they are not making the multi stage systems any more. You can only get a single stage or variable speed inverter system. From what I read, Carrier is streamlining their offerings now that the Variable speed inverter systems are more common place.

Per Carrier:
Carrier has not stopped making multi-stage heat pumps. While they have introduced a new fully variable Infinity Greenspeed heat pump model, they still offer two-stage and multi-stage options like the Performance 17 2-Stage air conditioner,

Here's a more detailed explanation:
Two-stage and multi-stage heat pumps are still available:
Carrier continues to offer two-stage heat pumps, which provide consistent comfort and energy savings.
Fully variable heat pumps are also an option:
The new Infinity Greenspeed heat pump offers a fully variable speed compressor, providing even more precise temperature control and efficiency, according to Carrier.

"Five-stage" line is discontinued:
The previous five-stage heat pump model has been discontinued, but the overall multi-stage options are still available.
Focus on efficiency and comfort:
Carrier is emphasizing the benefits of multi-stage systems, such as improved comfort, energy savings, and humidity control.

I just got an estimate from Sun Kool for the Carrier Infinity Greenspeed 4 ton. $14,951. The same in a 3 ton from Sun Kool $13,146. Manual J is the industry standard for sizing a heat pump. There is free software on the internet like CoolCalc Manual J .

The salesman claimed to me I would save 35% on my heating and cooling portion of my energy bill, not on my energy bill. I spent $103.00 on cooling in June and in October I spent $8.00. This is according to SECO. In the winter months I may not even turn the heat on.

Rule of thumb, The monthly savings per 1.0 unit increase in SEER = 15.6 kWh × $0.14/kWh = $2.20 per month. My present Carrier installed in 2009 is 15 SEER so if I go to a 20 SEER $2.20 X 5 =$11.00 per month. X 12 = $132 per year and for 10 years $1320.00. Is that on the low end or on the high side? I hope that is on the low side.

Sounds good! What is included with that price? Surge protector? Over/under voltage device? Air filter cabinet? Any other details on what they are doing for that price? Also, are you sure the new unit is 20 seer? From what I can see the 3 and 4 ton units are 23 SEER. What is the model # of the condenser they are estimating?

Includes permit (Sumter County) surge protector, new line set run through attic, new circuit breaker, wiring as needed, , new concrete pad, filter, 1st year maintenance visit,
Top Tech Filter Cabinet #TT-MAC-2122 (4 inch),
Thermostat Carrier SSYTXCCITC01-C,
Carrier Condenser Unit 27VNA036A003,
Carrier Fan Coil Unit FE5BNXC36L00,
Electric Heat Strip Kit AFAEHL05N01,
10 year parts, 10 year labor warranty
Installed in one day with orientation visit the following day.

The one thing I don't like about the Infinity System is the Thermostat. Actually I have watched a few videos on it and if it does all it shows in the videos it is a great T-stat. But the communication protocol is proprietary and it is the only Thermostat that will allow all the features of the Infinity System to function. Ecobee makes one that will work but all the features of the system are not available.

All good just we all got the 27vna03 which is 24 seer. Not sure why carrier has both systems.

You got a deal Congrats. This is the one they quoted for me.

From the Carrier web page:
Energy Star logo
Puron Advance logo
Description

27VNA036A003
27 = Puron Advance™ (R-454B) HP / Refrigerant & OD Type
V = Variable Speed / OD Design type
N = Infinity® / Tier
A = Initial Series / Major Series
0 = 20 SEER2
36 = 36000 Btuh (nominal) / Nominal Cooling Capacity
A = Standard HP / Variations
0 = Standard / Feature
0 = Not Defined / Open
3 = 208/230-1 / Voltage

https://www.carrierenterprise.com/se...ry=all&query=*

So Carrier makes 3 infinity systems, 27VNA0 which is the 20 seer system, 27VNA1 which is the 21 seer system and the 27VNA3 which is the 23 seer system. Other than efficiency, they look identical. My guess is they are offering you slightly different efficiencies for more price selection in this series.

Let us know if you go for this system.

I'm not sure on the SEER efficiency savings but so far, I'm saving about $50/month over my single speed basic 15 Seer Carrier system installed circa 2016. Your savings will also depend on what temperature you set your thermostat to for cooling and heating and the size of your home.

Put in a Trane 4-ton Variable speed system 4 years ago. We also did a 4-zone system. Zoning added almost $4K to the price. I believe we have saved close to $4K to date as this system is extremely efficient. I say that because our SECO bills in the heat of the summer are just a touch over $100. Last month $107 and projected for this month $113. 2100 sq ft home. Average temp setting in home, 77 per Trane app.

That's a great system! It's good to get some real savings numbers. Thanks for the feedback.:BigApplause:

Yes, it is amazing for sure. This system rarely runs over 50%. At this moment on a hot 92-degree midafternoon, it is running at 28%.

Same here. My system usually runs at 45-50% even in this very hot humid weather.

After reading more and more about electric rates going to increase over the next couple of years, the tarriffs increasing the pricing of all HVAC systems, and the Federal tax credits going away this year, I'm sure myself and my neighbors made the right decision replacing now with the full 10 year parts and labor warranty vs waiting a year or two and paying a lot more money for these high efficiency systems. Especially since we use A/C most of the year when electric goes up, everyone is going to be scrabling for a higher efficiency system.

I remember my neighbors laughing at me re-painting my home before paint went up in price then two years later they were all paying almost double what I paid for the same job and paint!

Coming down soon for the design meetings when all the options will be finalized. Do we get the option of choosing different HVAC options like single speed vs variable speed, etc? I am very concerned about the humidity control and the possibility of mold... The comments about the variable speed running on humidity control mode makes me feel comfortable

When I asked my sales rep if this was an option she simply sent me a sheet detailing the " base" default option. So I'm really hoping that this is an option I can upgrade at build time

First of all, mold will not be a problem either way. However, the sales rep should be able to provide the available options and the cost.
I would not accept her answer.

If you are building new you should have the option of the Carrier Performance base Single Stage unit, Carrier Performance 2-Stage unit and the Carrier Infinity Variable Speed unit. The difference between the systems is SEER efficiency, 16, 18 and 24 SEER respectively and temperature and humidity control. The Carrier Infinity will control the temperature and humidity the best and qualify for the $2,000 Federal Tax Credits which ends this year. So, if you have a choice and can affort it, get the Carrier Infinity. Just remember with these models they will try and add on all kinds of air purification extras such as UV lights, etc.. You don't need them and can always add them later. Just get the system without all the accessaries. As far as mold, generally you shouldn't have to worry but I can tell you with my Carrier single stage base unit, my hepa filters would get some mold over time but with my new Carrier Infinity Variable Speed system, the humidity stays exactly where I set it and no more mold issues. Why is this? Because with the single stage unit, when it cools it removes humidity so depending on how long it runs will determine how much humidity it removes. It will vary the temperature as much as 3 degrees to try and hit the humidity target you set. With the Carrier Infinity variable speed unit, once it reaches the temperature set point, if the humidity set point is not reached then it will run in "dehumidify" mode which is at a very low speed to remove the remaining humidity without lowering the temperature as much. That's the big difference beyond efficiency between the systems. The basic runs 100% On and 100% Off and the Infinity runs variable from 20% to 100% only at the speed it needs.

Agreed. From experience with friends who recently built here in the Villages, unless it's a spec home, you should be offered options on the HVAC system. Not everyone knows this or knows the difference between the systems and go for the cheapest option.

I will tell you, this is not something that you will upgrade when you move in. It's a 10-15 year investment. So I would investigate and make any changes if that's what you decide to do.

Keep in mind that the $2000 federal tax credit only applies to improvements to an existing home, not new construction (Energy Efficient Home Improvement Credit | Internal Revenue Service).

Greg, thanks for that correction.

[QUOTE=GregR;2445763]Keep in mind that the $2000 federal tax credit only applies to improvements to an existing home, not new construction

Ohhhhhh - bummer about the tax credit not being applicable here. I still think that I am very likely to go with the extra expense of the variable speed system. I know I won't recoup the extra cost in utility bill savings, but the idea of a more consistent temperature really appeals to me. Earlier in this thread someone described the need to put a blanket on when the system kicked on..... Yeah I really dislike those wild temperature swings. I did notice it in the house we were staying in for our lifestyle visit.

Also - since we will be snowbirding for the first few years (not yet retired) - the house will be unoccupied often in the summer. I'm thinking that maybe I could just drive the system off humidity control level as opposed to temperature? Is that even possible? Ideally if I could have the system assure that my humidity is "safe", when unoccupied I really don't care so much what the temperature is (within reason).

Thanks for all this valuable info!

I replaced my 3.5-ton single stage 2009 system with a 4-ton Carrier Infinity system by SunKool 10 days ago. The work was done to my complete satisfaction and here are a few lessons I’d like to pass along:

Noise level: I would always hear my old system, both compressor and indoor fan, kick on and run as an annoying background noise. The new system’s sound levels are imperceptible.

Humidity Control: I didn’t use humidity control with my old system. The new system can be operated without humidity control or to a selected setpoint between 46 and 58%. I have tried different settings to minimize sub-cooling the home and have settled on 58%.

Air delivery: I’ve had to re-adjust my registers because the new system delivers a variable and often reduced amount of air to all rooms. Ironically my north facing bedroom was typically the coldest room in the house but was now the warmest so I had to adjust the damper. I also notice that cold air tends to dump out of the register instead of being previously diffused with room air at a higher velocity, so I now run the ceiling fan for better air distribution and comfort.

Thermostat: the Carrier t-stat and app provides minimal data versus the Nest t-stat I had with my old system. The new system allows up to 4 daily adjustable setpoints and provides a summary of daily energy usage for two days only. I cannot see what percentage that the system is operating unless I go into the setup mode at the wall t-stat. I am not able to override and run the system in the Fan Only mode. I could do much more with Nest.

Technical Support: I contacted Carrier via the app a week ago with a few questions. No response from them yet.

If you want to adjust the amount of air delivery there are settings on your Air Handler that can be adjusted. You can call your installer back to make any changes. You can also make an adjustment on the thermostat. You can change the air flow form Comfort to Energy Efficient which will increase the airflow for the cooling, heating and humidity independently but before doing this I would have them take a look at the air handler first to make sure it's set up properly since you shouldn't need to run your ceiling fans to get good circulation unless you have a special situation. Do you know the static pressure of your system which tells you if you have any duct issues? You can get it by going into the service menu on your thermostat but if you don't feel comfortable doing that, call them since this is a common issue people report. It should be less than 0.5 after it runs it's check when you first turn on the system or when it's running at 100% after. In my case, I not having any problems. All my rooms are within 1/2 degree of what the thermostat displays and the air circulation if fine but I have heard this feedback.

On the thermostat, I agree. It doesn't have the data capabilities as the Nest or the Ecobee but it does it's job well controlling the system. My temperature and humidity are accurate and constant and I'm saving about $50/month on electric so far.

The thermostat has an incedible amount of data if you go into the Service Menu but as for the app, If you go on to it on your phone, Click on the first page which shows "All Devices", then click on your "Home" and on the next page on the bottom click "Energy Insights" you will see if the AC, Electric Heat, and Fan are running and at what percentage or OFF. It also tells you your filter life. You are right, this information should be on the first page of the app. As mentioned if you go into the service menu on the thermostat, and go to the heat pump section, you can see all the pressures, super heat, subcool, temperatures, etc.. to make sure the system is running correctly without connecting any gauges or have the tech out as long a you understand what all the readings mean. I wish they had this on the app. There is also another Service app that you can download and connects to the condenser when you are near it outside via bluetooth. You have to log in as guest but you can see all the readings there as well. It's designed to be used by the tech so he doesn't have to go in your house to the thermostat to get these readings. I like this becasue I don't want the tech to keep putting their gauges On and Off my system and loosing a little bit of refrigerant each time but my guess is they do it anyway to make sure the automation in the system is giving them the right data I've been told.