how much should central AC run ?

[RicodJour]

While I always enjoy hearing tales about your brother-in-law and look forward to reading about him, I don't see what he has to do with the OP.

We have no idea how the OP's system was designed, whether the Manual J's were done or the cooling load just guessed at, whether the OP went with the lowest bidder, etc. The OP is not happy, and I agree that he should be happy in his own house. Whether the contractor undersized the system (which sounds like a definite possibilty) due to a mistake, ineptness or because the OP asked specifically for a 3-ton (or whatever) system, we don't know.

Obviously if the OP has a problem with his system and is not happy he should contact the contractor and have him take a look at the system to see if it's operating as it should. Maybe there's a leak, clogged filters - many things could affect the system's ability to cool. If nothing is amiss, then the OP can discuss his dissatisfaction with the system's performance and can discuss what can be done and on whose dollar.

Your categorically stating that a contractor has to "satisfy the customer" at all costs is naive and inflammatory. But I think you already know that.

R

[udarrell]

I just discovered that he has a 3-ton outdoor and indoor air handler and coil system. If you are cooling and additional 1800-sq. ft. of basement that changes the equation! Have your home checked and see what cooling Btu/hr it calls for; some utility companies will do it for you!

Yes, Colorado is Very Dry! Design at Durango Design is 87-db and 59-wb that charts to only around 20% RH. Denver at the high altitude is worse: Design is 91-db and 59-wb; it's literally off the charts.

A well insulated 1800-sq. ft. Ranch style home in that dry a climate ought to be easily handled by a 3-ton system. Here in a rather comparatively humid SW WI (Madison 88-db and 73-wb for a 49% RH) we have 2400-sq. ft homes being nicely handled by 2-ton systems.

How good are the techs that check your system? I believe there might be room for improvement; that merely an educated opinion as I don''t have any of the required relevant facts. Everything might be okay! During the hottest days it should run most of the time. - udarrell

[BocesLib]

You need to first ask yourself was the system working fine after they installed it or it just acting funny now???

I had a somewhat similar problem.

Last year I purchased a rheem high eff. central air system for my home. At first it worked pretty good. When the temps outside started to heat up the system wasnt performing well at all.

I took a temp reading at a few of the vents and noticed that it was only a 10 degree difference than the outside temp, oh no. (sort of explains why the system was on all the time and not really cooling the home)

I called up the installer and they measured the temp too. It was off.

Turns out there wasnt enough freon in the system in the first place. System ran day-n-night and couldnt keep up. They charged the system up and it was working great for the rest of the year.

This spring on the first warm day I decided to make sure the system was ok. Turns out the compressor wasnt turning over. I went through troubleshooting and found that the low pressure switch was tripped. I reset it and that didnt help. I called the installer and they found that there was NO freon in the system again. I almost went nutz (not in front of the tech though) Anywho... they did a leak check and found a pinhole leak in the system. They charged it up again and all is working well again.

So far so good.

[Rudy]

This is a crock. We commonly had 108 oF days in AZ and the ac had no problem keeping the house at 76 A 32 degree differential.

[Stretch]

I live in a 2000 square foot house in Hot, Humid Myrtle Beach South Carolina. I have a 2 ton heat pump with 4 KW strip heat. It does just fine.

The proper size for your house depends on YOUR house, climate, insulation, construction, glass area and direction and type, duct leakage, etc. It is possible that it is undersized but that can not be determined from here.

The temperature difference between the outside and inside is determined by your comfort level and your climate. Here in Myrtle Beach, we use

20 Degrees. IN death Valley you would Size for a lot more. The units are rated for ARI conditions. You should size them based on Manual J conditions. Your installing contractor should have done that. If you are not comfortable, he should make it right under warranty.

Did he seal your ducts?

Did he measure air flow?

Did he do a capacity check?

These are questions I would have for the installing contractor.

Stretch