[patandrose]

ok guys my house was built in 2005 its 1740 sq ft with vaulted ceilings in th living room and kitchen. my ac is 1.5 ton. i live in sw fl and the temps are in the high 90s during the day and very rarely are the under 80 at night. i have my ac set for 75 and my house wont cool below 83. i have no windows on the east or west side of my house and the north and south side windows are shaded. we have shaded the ac unit outside and the air handler is in the closet inside the house. the only opening to the attic is in the garage. all the windows and doors are sealed tight no air gets out or in. the ac runs constantly during the day. i guess i should also mention the ac unit is new just put in 2 months ago. i cant get my house to cool down. any suggestions on why it wont cool and what i can do to get my house to cool down? i have read some of the other posts but they just havent helped.

 

[hvac122]

If its only 2 months old then you should have the instalation company out to check it out. It should still be under warranty.

 

[gma2rjc]

My house was the same way. Even with a new A/C unit, the house wasn't cooling (except for the basement). I'm not sure this is the answer to your problem, but my attic wasn't sealed, ventilated properly or insulated nearly enough.

I sealed it, fixed the ventilation problem and brought the insulation from R-19 up to R-56 (approx.).

Now, when I've had my central air on this summer, the upstairs and basement feel like they're the same temp.

 

[Scuba_Dave]

Do you know if the vaulted ceilings have proper insulation & venting?
Is there a ridge vent & soffit vents installed?
Light colored roof or dark?
Check the attic insulation too

 

[hennyh]

Did the contractor do a detailed load calculation to arrive at 1.5T for your home? (or did they guess) Get them back out to your home and have them get it right.

1.5T sounds pretty wimpy for 1700+ sq ft, high humidity, high heat, vaulted ceilings, etc. The load calculation will give you that answer. After that it's a matter of tracking down other issues such as low air flow, ductwork problems, installation issues, etc.

 

[patandrose]

first of all thanks for the replys.:thumbsup:
there are ridge vents at the peak and soffits going all the way around the house. the roof is dark. as for the insulation my husband said its very well insulated he said its a foot thick. do you know if the insulation is to extend to the soffits or should there be a certain distance from it? and also in the 4 bedrooms there are intakes that have 1 ft by 1 ft filters. and in the hallway we have the handler with a 2 ft by 2 ft filter. if the 2 rooms face direct sunlight during the day would the heat drawn into those filters cause the ac to work more. should we block the bedroom intakes or just leave them the way they are?

 

[deeze]

WOW... 1.5 ton unit? My 10x8 shed has a 1 ton window unit!!! My house which is 2300sf has a 4 ton. I live in NE Florida...

 

[kennzz05]

sounds mighty small for almost 2,000 sf. why does a 4 yr old home have a new unit? any idea what size unit was originally there?

try mrhvac.com and do your own heat load calculation, the link is all the way at the bottom of the page

 

[patandrose]

the house is 4 yrs old but we just bought it 2 months ago. the ac was stolen and when we bought the house the bank had to put a new ac in. we have had the ac man back out but he said it was working fine that there was nothing wrong. it just doesnt seem right that it runs almost constantly and nevers cools the house down below 83. we have the electric company coming out to do an energy survey to see what they can find. hopefully they can give us some answers and be able to help us fix the problem. thanks for your suggestions.

 

[Dave Carney]

It's too small! :=)

 

[deeze]

Yes... Dave's right... your answer is: it's too small.

 

[Scuba_Dave]

I'm not an HVAC guy, but one ton = 12,000 BTU
So you have 18,000 BTU in 1740 sq ft

I have 26,000 BTU cooling my 1st floor -1500 sq ft & I'm in New England
This includes a sunroom with an 11' ceiling
How insulated is "very well insulated" ?
Hopefully at least R38 or more in the attic, one foot thick should be R38

Do the ceilingsever feel warm/hot?
That would be an indication that heat is radiating down from the attic