how do I find the tonnage?

[sdeemer]

Hello,

I have a big problem with the A/C not cooling well downstairs in our home. We just had our house built 4 mo ag and is 2890 sq ft. I have had the builder's A/C warranty people over 6 times already to "rebalance" our zoned system but still our downstairs is 6-7 degrees above the set thermostat. (set at 76 - it is 81) after 4pm. I do live in Houston so it is quite hot here.

I think there should have been 2 units for our house, but they say our house is "rated" for 1 unit. It is a 13 seer Lenox. Can you help me find the tonnage so I can do some research on how many tons (or btu's) our home should have?

I am just a homeownwer so the simpler the better. The builder says 3000 sq ft homes don't need 2 units if they are zones.

thanks, susan

[newoldtech]

Give us the model number and we can tell you the tons.

Go to the outside unit and look for the manufactures tag on the unit. The model number will be there.

[sdeemer]

it is Lennox model # 13ACD-048-230-01

the builder did not give us any home owner instruction manual about our heat/ac.

[newoldtech]

It's a four ton unit. That is in the range of what your house needs. The only way to know for sure is if they did a load calculation before the job.

If you keep having problems, try calling Lennox directly.

[sdeemer]

thank you for the reply. since the A/C people are coming back out again monday (with an infared camera to check for problems) it is my right to ask them to do a load calculation? otherwise we may hire our own HVAC person to do check our load.

i had head somewhere that a home needs approx 30btu/ per sq ft. if this is true that would put our tonnage need at 7 - which must not be correct. if you know of any web sites i might be able to research this more - feel free to reply. i know david weekley does not want to put another unit in our house.

[re2ell]

Originally posted by sdeemer
thank you for the reply. since the A/C people are coming back out again monday (with an infared camera to check for problems) it is my right to ask them to do a load calculation? otherwise we may hire our own HVAC person to do check our load.

i had head somewhere that a home needs approx 30btu/ per sq ft. if this is true that would put our tonnage need at 7 - which must not be correct. if you know of any web sites i might be able to research this more - feel free to reply. i know david weekley does not want to put another unit in our house.


sdeemer, anyone who sizes a/c equpment by area is living in a fantacy world. a load calculation is the ONLY reliable and acceptable method to determine ones' needs.

you might have your installing contractor to verify airflow of the unit, many times insufficient airflow is the underlying culprit of uneven temperatures within a structure. (and just a short note on airflow measurements, and infrared detector won't give you quantity of air being delivered)

[jacob perkins]

Originally posted by sdeemer
if you know of any web sites i might be able to research this more - feel free to reply.

this is the website you need..but I just dont know of others...any way there is a bullseye link somewhere,here:

http://hvaccomputer.com/talkref.asp

I guess follow that link to do your own calc.
(and tell um fat eddy sent ya)

remember that sometimes the size of mechanical equipment is fine but other issues are to blame for not cooling

[BaldLoonie]

What you need is a GOOD dealer. I may get some guys mad at me but many dealers willing to work for the peanuts and headaches that comes with a warranty company aren't what you want in your home.

I know we have some Houstonians (is that what you are) on here. Al, isn't that your stomping grounds? Who else?

[danglerb]

4 month old house and the AC can't get the downstairs below 81 degrees? or is it that downstairs is 81 when upstairs is ok?

I would make it clear to the builder what you expect then hold his feet to the fire and let him sort it out. How they do it, what sort of calculations, thats more the contractors concern then mine.