Central Air Conditioners

[Freedom56]

The Trane central A/C and heating unit in our Florida condo is 9 years old and have not had any issues with it. We are only there a few months per year and keep the temperature at 72 degrees when we are there and 76 when we are not. We change the filter at least once per year. I installed a Wifi thermostat to control it remotely. We have a Lennox A/C and heating unit in our home in Southern California and it has been operating since 1996. I repaired the controller board twice (replaced relays that burned out) and replaced the controller board once. I also replaced the exterior disconnect switch once. I also installed a Wifi thermostat on this system.

 

[REWahoo]

JP.mls, for what it's worth, Consumer Reports says Rheem has a reliability rating of 3 out of a possible 5, placing it in the middle of the pack of the 21 brands surveyed. The brands with the highest reliability (4/5) and owner satisfaction (5/5) ratings were Carrier, Lennox, Bryant, American Standard and Trane. This was from a survey of 21,000 CR readers in 2018.

 

[Al in Ohio]

I'm considering a new central air conditioner for my Florida townhome.

Two questions:
- How long have you gotten a central air conditioner to last in a fairly hot environment? Florida/Arizona etc.
Mine is 11 years old, and I've been told that is towards the end of it's life for Florida use.
I don't want it to fail right in the middle of summer, when I'm out of town. That is why I'm considering being proactive on the replacement.

- Any manufacturers you have had good luck with?
I was ready to buy a Lennox through Costco, and then read some not very good on line reviews. I'm not sure if I can trust on line reviews in general, that is why I'm asking this forum.

Thanks, JP

I am a retired Mechanical Engineer who did decades of HVAC design and specified lots of systems. For reliability and durability I can tell you Carrier and Trane are the top end. Lennox is middling. Rheem is budget.

Gas fired furnaces have a 20 year life expectancy and outside condensing units 15.

 

[Al in Ohio]

The Trane central A/C and heating unit in our Florida condo is 9 years old and have not had any issues with it. We are only there a few months per year and keep the temperature at 72 degrees when we are there and 76 when we are not. We change the filter at least once per year. I installed a Wifi thermostat to control it remotely. We have a Lennox A/C and heating unit in our home in Southern California and it has been operating since 1996. I repaired the controller board twice (replaced relays that burned out) and replaced the controller board once. I also replaced the exterior disconnect switch once. I also installed a Wifi thermostat on this system.

When not occupied keep your setting at 82 or 84 and save some money. 76 is too low for an unoccupied setting.

 

[Al in Ohio]

Atmsmshr,
A recommended installer wants to sell me a Rheem. I'm considering this, but possibly waiting until my unit fails.
He said most brands use the same main component suppliers (coil and compressor).
The premium brands use proprietary components that are more expensive, and harder to get.
Thanks for telling me the Rheem unit seems to be holding up.
I can find negative reviews on basically every brand. Including Rheem and the higher priced Lennox being sold through Costco.
JP

Raheem is a budget brand. You need to realize that most installers represent just one brand. They are licensed to carry and purchase that one brand for wholesale pricing under the condition it’s the ON
LY brand they install.

 

[atmsmshr]

Raheem is a budget brand. You need to realize that most installers represent just one brand. They are licensed to carry and purchase that one brand for wholesale pricing under the condition it’s the ON
LY brand they install.

In the salt air of a barrier island - I am not planning on paying more than necessary for a unit that will have a condenser rust out in 10 years.

 

[eytonxav]

I do not think you can go wrong with an American Standard or Trane, but more importantly is finding a contractor that will size and install the system properly. Also there is a lot of potential loss in the ductworks insulation if it is in an older home.

 

[Badger]

I am a retired Mechanical Engineer who did decades of HVAC design and specified lots of systems. For reliability and durability I can tell you Carrier and Trane are the top end. Lennox is middling. Rheem is budget.

Gas fired furnaces have a 20 year life expectancy and outside condensing units 15.

Al, I have heard there is a canned spray to protect the outside aluminum cooling fins from corrosion/oxidation and extending their life. Any truth in this? Any recommendations?


Cheers!

 

[Scubamax]

I'd be interested in hearing what type of anomalies you found.

I would have to pull out the service sheets for the specifics, but it was regarding a something to do with the pressure variance in the line set during the cooling cycle. (The outside units are at the outer limits of distance allowed from the house, which could contribute to the issue). The tech during a normal PM visit spent most of the day troubleshooting the issue and contacted one of his colleagues who serviced it 6 months earlier. Evidently Trane back in 2016 when the unit was manufactured was using a motherboard (or whatever) that sometimes might have who knows contributed to this intermittent issue.

So we replaced the board (under warranty) and the problem appears to have been solved. The alternative would be to dig up the coolant line set to see if there was any obstructions etc. That was something I did not want to do if at all possible.

I know this is not the best technical explanation, but that's my story.

 

[Sunset]

Al, I have heard there is a canned spray to protect the outside aluminum cooling fins from corrosion/oxidation and extending their life. Any truth in this? Any recommendations?


Cheers!

Never thought of it, but that doesn't stop the comment

My first thought would be some thin oil sprayed/misted on them. Probably synthetic 0W.

 

[Badger]

Al, I have heard there is a canned spray to protect the outside aluminum cooling fins from corrosion/oxidation and extending their life. Any truth in this? Any recommendations?


Cheers!

I found a few products that claim to be an answer but then it could be snake oil too.
Nyalic, Permatron, Coil Shield, and Force5 HVAC spray.
If any of these really work it could extend the life of the HVAC by a few more years if you live near the ocean.


Cheers!

 

[Freedom56]

When not occupied keep your setting at 82 or 84 and save some money. 76 is too low for an unoccupied setting.

The association rules are that you have to keep the thermostat at 76 maximum for cooling. At 82 to 84, there would be too much humidity that will eventually corrode the electronics in your home. Our hi-rise condo is on the intra-coastal so there is a lot of salt air also. Humidity and salt air is not a great combination for electronics.

 

[Sunset]

The association rules are that you have to keep the thermostat at 76 maximum for cooling. At 82 to 84, there would be too much humidity that will eventually corrode the electronics in your home. Our hi-rise condo is on the intra-coastal so there is a lot of salt air also. Humidity and salt air is not a great combination for electronics.

I see two ways to read this.

do they mean don't cool more than 76, ie not at 74 or 72. ?
Or
do they mean don't let the heat go up to 78 or 80 ?

How would they even know ?

 

[ncbill]

The association rules are that you have to keep the thermostat at 76 maximum for cooling. At 82 to 84, there would be too much humidity that will eventually corrode the electronics in your home. Our hi-rise condo is on the intra-coastal so there is a lot of salt air also. Humidity and salt air is not a great combination for electronics.

I'd worry more about mold more...grandmother "helpfully" cut off the A/C at her place at the beach and next thing you know we were scrubbing mold off the drywall.

 

[Music Lover]

Also there is a lot of potential loss in the ductworks insulation if it is in an older home.

True, if the ductwork is in the attic. If the ductwork is a conditioned basement (what I have) then there are no losses, but potentially less airflow in some areas.

 

[Freedom56]

I see two ways to read this.

do they mean don't cool more than 76, ie not at 74 or 72. ?
Or
do they mean don't let the heat go up to 78 or 80 ?

How would they even know ?

Maintenance people periodically check thermostats in all units at our condo. They don't want temperatures going above 76 degrees in the condo units. The common areas are maintained at 70 degrees. Mold is another issue with high humidity. I know someone who lives in a new home in Wellington Florida. He keeps his thermostat at 79. His house always feels humid and has a damp smell. He has replaced his refrigerator compressor two times in the past 6 years. Many of his bathroom fixtures door stops are showing signs of pitting from corrosion His house is only six years old.

 

[Time2]

I'm in the Florida Panhandle the original furnace that the house was built for lasted 32 years. I'm at 13 years on the replacement.
The advantage of a newer unit is efficiency, lower cost to operate.
But, I also believe the new units don't lasts long. Mine lasted 32 years, I have a friend that just replaced his 36 year old unit. Idon't think you will get that out of any modern unit.

Admittedly, air conditioners in the Panhandle won't be run as much as one in Tampa or Miami.

 

[Time2]

Maintenance people periodically check thermostats in all units at our condo. They don't want temperatures going above 76 degrees in the condo units. The common areas are maintained at 70 degrees. Mold is another issue with high humidity. I know someone who lives in a new home in Wellington Florida. He keeps his thermostat at 79. His house always feels humid and has a damp smell. He has replaced his refrigerator compressor two times in the past 6 years. Many of his bathroom fixtures door stops are showing signs of pitting from corrosion His house is only six years old.

At one time, I ran a dehumidifier in our home, I found I could run the temperature 4F* higher if the humidity was below 40% and be very comfortable. I stopped because I didn't have a good place to put the Humidifier. It produced a lot of heat so out foyer got hot, and it was just more to cool, so, I don't think it was economical, but it was comfortable.
The ideal would be a dehumidifier that sent it's heat outside.
Yes, I'm aware that a dehumidifier is basically an air conditioner optimized to collect water from the air. I'm not sure how much it is optimized over an air conditioner though.

 

[Al in Ohio]

In the salt air of a barrier island - I am not planning on paying more than necessary for a unit that will have a condenser rust out in 10 years.

When I specify units in salt air environments I require the condenser coil to be coated with a 5000 hour salt spray rated baked on coating. One excellent brand is Heresite. Trane and Carrier offer this option even for residential units.

 

[Al in Ohio]

Al, I have heard there is a canned spray to protect the outside aluminum cooling fins from corrosion/oxidation and extending their life. Any truth in this? Any recommendations?


Cheers!

Do not use a canned spray. There is a factory applied coating option. It is dipped and baked on. See my response to another related post. It is about a $250-$300 option for a residential unit, but will add many extra years life to condenser coils in salty climates.

 

[Al in Ohio]

True, if the ductwork is in the attic. If the ductwork is a conditioned basement (what I have) then there are no losses, but potentially less airflow in some areas.

There would still be losses in the conditioned basement, just not as high. A cold duct will carry 55-60 deg air. The basement will be warmer.

 

[Music Lover]

There would still be losses in the conditioned basement, just not as high. A cold duct will carry 55-60 deg air. The basement will be warmer.

Although there could be leakage in the ducts no energy is lost as it stays in the house....it just may not go exactly where you want. I use my basement as living space so any duct leakage simply warms or cools it a little more. That's easily fixed by adjusting the dampers to balance airflow. 100% of the heat or AC remains in the house.

However, in an unconditioned attic the energy is lost to the outside.

 

[Sunset]

Although there could be leakage in the ducts no energy is lost as it stays in the house....it just may not go exactly where you want. I use my basement as living space so any duct leakage simply warms or cools it a little more. That's easily fixed by adjusting the dampers to balance airflow. 100% of the heat or AC remains in the house.

However, in an unconditioned attic the energy is lost to the outside.

That is how I view it, so in Winter is when I make a lot of use of the oven, it not only cooks my food, but the excess heat takes the place of some furnace heating.

 

[Music Lover]

That is how I view it, so in Winter is when I make a lot of use of the oven, it not only cooks my food, but the excess heat takes the place of some furnace heating.

We do the same....lots of baking and homemade pizzas in winter. In summer we use the barbeque almost daily and if an oven is required we'll use the toaster oven if possible.

 

[Al in Ohio]

Although there could be leakage in the ducts no energy is lost as it stays in the house....it just may not go exactly where you want. I use my basement as living space so any duct leakage simply warms or cools it a little more. That's easily fixed by adjusting the dampers to balance airflow. 100% of the heat or AC remains in the house.



However, in an unconditioned attic the energy is lost to the outside.

If it doesn’t go where it’s needed it’s not efficient or as effective. You will run it more to make up for those differences. It’s a different kind of loss.