[bigb1026]

Standard vs Two Stage Central AC Unit

Hello We are building a home in Port St. Lucie, Fl. The builder offers a standard Carrier central AC unit at no additional change (I don't have the exact model number yet, but they state minimum 14 SEER and I'm sure it's the cheapest contractor model they can find), but also offers an upgrade for a two stage Performance Series with minimum 16.5 SEER rating for $. I'm guessing that's a bit of a gouge. My instinct is to take my chances with the standard unit and keep the $ in my pocket, thinking in this climate the unit will die years before I have recouped the initial $ investment. BUT, I am wondering if I am being shortsighted. If we decide to upgrade to two stage in say 10 years, will we have to upgrade not only the compressor but the air handler and whole shebang as well?? Or could we just use the same handler, thermostat, etc.? In other words, by going cheap today, are we condemning ourselves to less-than-optimum units forever? Need some advise? Would the $ be a worthwhile investment or not....what would you do? Thanks.

 

[BaldLoonie]

We can't talk $ and one of my fellow Mods will delete it but since it is asking if the extra is worth it, I'll answer. NO. Even in steamy Florida, a well built new house wouldn't save that kind of money in the unit's lifetime. Do it later? No, because odds are they are putting in a bare bones air handler that won't support the high end A/C.

 

[teddy bear]

Now is the time to consider all the options regarding conditioning the home.
If you want real control of temperature and humidity throughout your home during FL's variable weather, either of the a/cs will provide the temperature control. Sized and set-up correctly the single speed will provide temp/%RH during peak cooling loads during +50% load cycles. The two speed will provide reasonable humidity control down to 25% cooling cycle depending on the outdoor dew point and 3^F overcooling.
None of these options will maintain 50%RH during cool evenings and rainy days. The higher SEERS are worth <5% reduction per SEER number for the season(my rough guesstiment). We must have some expert on the site that can state that better my guess. The higher SEER a/cs have larger coils that retain more moisture which makes humidity control more difficult.
If you want real control of temperature and %RH for minimal investment and reasonable service cost, go with 14-16 SEER single speed a/c and (here is a twist) a small whole house dehumidifier, like the site sponsoring Ultra-Aire . Set the temperature and %RH you want and enjoy. The properly setup a/c will maintain the set temperature and <50%RH down to a 50% cooling load cycle. As the cooling cycle declines below 50%, the %RH will exceeds the 50%RH setting of the dehumidifier, activating the dehumidifier. As the cooling load decreases to zero, like cool evenings or rainy days/weeks, the properly sized dehumidifier will maintain 50%RH. When the home is unoccupaied, the a/c can be turned off and the dehumidifier will maintain <50%RH for pennies an hours verses trying to cool the home enough to remove moisture. Cooling will not keep the home dry during cool weather.
A single speed a/c and dehumidifier cost about the same as a two speed a/c.
I this is a curve, but now is time go 21st century with conditioning equipment in your home. Imagine real temperature and %RH control with simple equipment and reasonable investment/maintaince cost.
Your thoughts? Search my posts for a summary of all of problems we have encountered.
Regards Teddy Bear.

 

[udarrell]

You will seldom get near the Rated SEER...!

The general consuming public needs HVAC education on PublicTV in the worst way, so that they get the efficiency that they are paying toreceive.
Public TV has wood work shows we need HVAC SHOWS

American PUBLIC TV produces CREATE; send them a request to produce shows focusing on HVAC efficiency:

Everyone! needs to write to:​

https://www.aptonline.org/aptweb.nsf...m&type=Viewers

Explain that, Average AC efficiency is only less than 60%... that has to change...!

Please help me get HVAC on Public TV...!
We have to be enabled due to increased efficiency to transition to clean renewable energy sources reducing the rate of climate change. ... Please ALL HELP... I AM TOO ILL TO BE EFFECTIVE - PLEASE ALL HELP... ..​

​

 

[beenthere]

2 stage equals more comfort. So what is more comfort worth to you. Let that be what makes your decision for you.

 

[pecmsg]

I'm more concerned with how either system is sized and installed. Is the installing contractors loyalty with you or the GC that gives him a lot of work. Flex duct, hard duct or fiber board? Installed for ease of service?

 

[timjimbob]

These days, Today's two stage units are very simple and identical technology pretty much across the manufacturers. What this means to you. Most techs know how to fix this without refering to serrvicing manuals and parts are cheap because they are widely available, not OEM.

 

[teddy bear]

I am getting confused.
https://hvac-talk.com/vbb/showthrea...hread.php?2200530-Carrier-Central-AC-Standard-vs-Two-Stage&highlight=teddy+bear

Anyway, consider this.
Regards Teddy Bear

 

[Bazooka Joe]

If you do decide to go with the higher SEER unit ( minimum or up to 16.5 SEER ) have them prove to you your getting at least that number by asking them for the AHRI number before agreeing.

You may actually qualify for rebates also if you go with that higher SEER unit.

One source: http://www.dsireusa.org/

Make sure to get your system registered, as when dealing with builders sometimes registrations falls through the cracks..

 

[beenthere]

Merged threads.