Re: new HVAC not cooling

That is a lot smaller than I would have guessed. I too am in a 1500 square foot house, but in the northeast, have 3 tons of a/c, and probably average about the same electricty cost as you do, but I have a 60 year old house with much less insulation and never need to pull the temperature down more than about 25 degrees, usually only 15 degrees. I also have a hefty winter gas bill for heating. I would have imagined that Phoenix was a lot more tonnage of a/c but apparently not.

Smarty

"Wayne Boatwright" <wayneboatwright@xxxxxxx> wrote in message news:Xns9AB9DD05016DDwayneboatwrightatcox@xxxxxxxxxxxxxxxx
It's a 3 ton high efficiency unit. House is 1500 sq. ft. The walls have a
6" insulation space with R50 insulation, as does the roof. The house is 1-
1/2 years old. We're on "averaged billing" which runs $165/mo. year round.
It's also an all-electric home.

Wayne...

On Tue 10 Jun 2008 06:56:12a, Smarty told us...

Wayne,

Your reply makes me curious........how many tons of a/c do you need to
be able to get a 50 degree temperature drop for how many square feet of
living space? What would be a typical electric bill during the summer
months? Thanks,

Smarty


"Wayne Boatwright" <wayneboatwright@xxxxxxx> wrote in message
news:Xns9AB8D1A26A2FDwayneboatwrightatcox@xxxxxxxxxxxxxxxx
On Mon 09 Jun 2008 06:52:50p, Edwin Pawlowski told us...


"CJT" <abujlehc@xxxxxxxxxxx> wrote in message
news:484DAF88.8070900@xxxxxxxxxxxxxx
thewifeunit@xxxxxxxxx wrote:
We recently had a contractor install a new unit (a Bryant Puron 2.5
ton in a 1500sq/ft 3br/2ba home) a couple of months ago. This week
we've had some really warm weather with temperatures in the 90s
nearing 100 degrees. The problem is the unit is not cooling the
house. The unit runs all day and doesn't drop the temperature below
78 degrees. Our older unit never had this problem.

We called the contractor that installed the unit out and he said
that was normal. He told us that these units won't cool more than 20
degrees below the ambient air temperature. He also said that the
fact that our ducts are in the celing makes this problem worse.
Something doesn't sound right here. I mean, our old unit cooled the
house fine and that unit was smaller (2 ton).

What's going on here? Is he correct, ignorant or simply lying? Can
you guys educate me on this? Should this unit be capable of cooling
the house better than it's doing now?

Btu is Btu. If the new unit is larger, it should cool to a lower
temperature than the old one. Proper sizing aside, the higher
capacity can remove more heat. Proper sizing gets into things like
humidity control where to big is no good. If the 2 ton unit was good,
the 2.5 ton should be at least as good at reducing the temperature.

I'd do a quick check of the basics first. Are the duct leaking? Was
something left undone or is airflow blocked? Check the temperature of
the air entering and leaving the AC. It should have about a 20 degree
drop across the coil. Cooler at night with no sun load? By cooler, I
mean the differential between outside and inside temperature.
Personally, I think there is a problem and since it is new, get him
back to check things, such as the pressures in the unit. There may
have been a leak.

There is a lower limit, of course. At 100 degrees, a properly sized
unit won't get it much more than 20 to 25 degrees cooler than outside,
but if the old one did, the new one should.

The design and sizing of a system is also somewhat dependent on where
you live. We live in the Phoenix area. Few people here would be happy
with 95 degrees inside on a 120 degree day, a 25 degree differential.
We can easily cool our house down to 70 degrees on a 120 degree day,
although we usually keep it at 75 degrees.


--
Wayne Boatwright
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Monday, 06(VI)/09(IX)/08(MMVIII)
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If laughter is the best medicine, shouldn't we be regulating it?
-------------------------------------------








--
Wayne Boatwright
-------------------------------------------
Tuesday, 06(VI)/10(X)/08(MMVIII)
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He has the right to criticize who has
the heart to help. - A. Lincoln
-------------------------------------------




.

Relevant Pages

  • Re: new HVAC not cooling
    ... It's a 3 ton high efficiency unit. ... House is 1500 sq. ... 6" insulation space with R50 insulation, ... The unit runs all day and doesn't drop the temperature below ...
    (alt.home.repair)
  • Re: new HVAC not cooling
    ... The house is ... ton in a 1500sq/ft 3br/2ba home) a couple of months ago. ... The unit runs all day and doesn't drop the temperature below ... Cooler at night with no sun load? ...
    (alt.home.repair)
  • Re: new HVAC not cooling
    ... ton in a 1500sq/ft 3br/2ba home) a couple of months ago. ... the house. ... The unit runs all day and doesn't drop the temperature ... Cooler at night with no sun load? ...
    (alt.home.repair)
  • Re: new HVAC not cooling
    ... ton in a 1500sq/ft 3br/2ba home) a couple of months ago. ... The problem is the unit is not cooling the house. ... The unit runs all day and doesn't drop the temperature below 78 ... The "20 degree" rule of thumb is across the A/C. ...
    (alt.home.repair)
  • new HVAC not cooling
    ... We recently had a contractor install a new unit (a Bryant Puron 2.5 ... ton in a 1500sq/ft 3br/2ba home) a couple of months ago. ... The problem is the unit is not cooling the house. ... The unit runs all day and doesn't drop the temperature below 78 ...
    (alt.home.repair)
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