Just an uneducated consumer with a SEER 21 AC
Our AC broke and my mother was really cranky in the hot humidity of VA. So she just wanted to get something into the house and get cool again. I sent her a ton of links to ACCA website, NATE certification website, and printed off the checklist for a manual J installation so that she could make sure the contractor was doing it right. But i dont know if he did a load calculation or not. He gave us a Carrier unit, 21 SEER that jumps from a 2 ton to a 3 ton depending on the work it needs to do to stay cool. Now that we have this super piece of equipment, what do i need to do to make sure that it is working as efficiently as possible? What about mini-duct air distribution? because i am sure we are losing a lot in old ductwork. Did we just waste a ton of money?
kspencer, was it just the a/c that was replaced, or did your contractor replace the furnace (air handler) as well?
Did the contractor do a load calculation before the equipment was quoted?
If the load was properly calculated, all you need to do is have an HVAC professional perform semi-annual preventative maintenance which will include checking airflow, refrigerant pressures, condenser coil cleaning (and evap coil if necessary), among 20 - 30 other items (depending on contractor). All you really need to do is change the filters regularly and set the thermostat to an appropriate setting (htg- 66 to 70 deg F., cooling 72-78 deg F.).
Last edited by CincyHVAC; 06-26-2008 at 05:38 PM.
Reason: adding information
thanks...too bad i work all day so my mother was the one to deal with the contractors. yes it was just the ac, but i have not clue if they did a load calculation, and i dont think my mother does either. But it can change from a 2 ton to a 3 ton, so wouldnt that pretty much cover it? my house is probably 2,500 square ft...is it possible to have a system that is too good?
What size was you old A/C.
It was just the A/C, did they replace the idoor section also.
A 21-SEER system is awful high.
Originally Posted by kspencer
If you deal with high humidity, a lower EER & SEER might have been a better match for those conditions.
How do you think it is doing?
The ductwork & air handler's airflow are extremely important.
TROUBLE SHOOTING DATA
Age a unit & SEER Rating ________
Square Footage of home & major city near you __________
Out-Door temperature: _____________
Outdoor condenser’s DB discharge-air-temperature _____
In-Door temp DB and WB: ___________
Total-ESP/ air flow in CFM: _____________
Return air temp DB and, WB, or %RH: ____________
Supply air temp DB and, WB, or %RH: ____________
Which stage was it operating in with above data _______
My advice: get a low cost humidity gage at a local hardware store & see what the percentage-RH is in your home, I can cross-reference that to the wet bulb depression.
Just click the "Quote" button & fill in all the questions you can.
Then, perhaps we can provide a ballpark opinion on what it is going on.
At 2500 square feet, I would be concerned about the system being too small and not about being too good. Double check the square footage of your home. I did a quick load calc. based on only square footage (not being able to see about windows, insulation, age of home for air infiltration purposes).
beenthere also asked what size your old a/c was. It would help.
It's better if the indoor section is variable speed for that A/C... What's the indoor model number(s)?