Yet another AC question (how much, attorney, house)

[nightgirl151]

Hi all....

I have a couple of questions for you...I have a house built in 2010, single story, 2175 sq ft, ten foot ceilings...90% shade screens on all windows, r38 in attic, no radiant barrier...And only 1 AC unit 13 seer

So here are my problems...Our house is terribly warm, we have had the builder come out and check the AC ductwork and no leaks, but you walk into our bedroom (SE corner of house) and it is literally 5 degrees warmer..And feels like no air movement in that room

So they say you can close vents in unused rooms, but keep it al less than 25% of total vents on house...if I close them will it push more air into the master bedroom? Or is it better to leave vents open and just leave the doors shut? is ther anything else I can do to improve air flow in the house?

Just to give a point of reference, we keep our house at 84 during peak hours 81 off peak..and we were having electric bills over 300 last summer...no pool..only 2 adults living in the house, run dishwasher, washer,dryer all off peak.....any suggestions?

[khuntrevor]

US Homes did something like that to my parents in 1999 for 223,000. Sky high bills...you would think the power company was paying them for poor design. And those flexi-ducts???? May I ask, who your builder was/is?

[khuntrevor]

the air coming out of the vent closest to the intake should be 25F cooler......a good place to start. At least you will know if the unit is working properly.

[observer53]

And, you can get an "air balancing" as well, moving the most air into the ducts in the rooms that need it the most.

[ReadyFreddy]

Originally Posted by nightgirl151

Hi all....

I have a couple of questions for you...I have a house built in 2010, single story, 2175 sq ft, ten foot ceilings...90% shade screens on all windows, r38 in attic, no radiant barrier...And only 1 AC unit 13 seer

So here are my problems...Our house is terribly warm, we have had the builder come out and check the AC ductwork and no leaks, but you walk into our bedroom (SE corner of house) and it is literally 5 degrees warmer..And feels like no air movement in that room

So they say you can close vents in unused rooms, but keep it al less than 25% of total vents on house...if I close them will it push more air into the master bedroom? Or is it better to leave vents open and just leave the doors shut? is ther anything else I can do to improve air flow in the house?

Just to give a point of reference, we keep our house at 84 during peak hours 81 off peak..and we were having electric bills over 300 last summer...no pool..only 2 adults living in the house, run dishwasher, washer,dryer all off peak.....any suggestions?

Your bills are similar to mine in an older house with a pool, but mine would go up to about $400 in the worst of summer, so not that wild-sounding. I try to do 83/on-peak, 80/off-peak, so a little cooler than you.

I think you can move your vent grills so the master gets some more a/c without totally closing off some rooms or shutting doors, can't you? If not, maybe some better vent covers would help? I heard closing off rooms isn't a great idea, because you don't want hot rooms in a cool house.

[Ponderosa]

You could have another duct installed in the warm room or, and maybe better because your return is probably not adequate in the first place, a return that would draw out the air from the bedroom creating a lower pressure there and increasing flow into that room.

I have given some thought to putting a window ac in my bedroom so that I can keep ice on the walls without having to waste money cooling the whole house to the same level.

[MotleyCrew]

What size is the AC unit? 13 s does not have anything to do with the size only the efficiency. The ducts could be inappropriately sized as well. I know our home's ac barely keeps the house cool and many builders here seem to cut costs with undersized units. We did add more insulation to the attic and it helped a bit. It is a battle here and I wish you the best.

[from nv]

If you do choose to close off the unused rooms, be sure to place a rolled up towel or two and the bottom of the door to keep the hot air from escaping. You may also want to check around your windows and see if any air might be coming through due to leaks, etc. and if so, put the towels there as well.

Another thing that may help is if you install the blackout shades or blinds to help keep the sunlight out during the day. Or you could hang a blanket or comforter over the window.

[Zippyman]

If the house is that uncomfortable, and almost new, I'd be looking for a contractor to perform a "manual D" calculation for the home, as well as a "manual J" calculation. You will have to pay for that, but the builder isn't going to admit that they did anything wrong without some proof on your part.

Manual j tells you how much heat loss/or gain is occurring in the room, manual d gives you ductwork sizes necessary to get that airflow. Then, your contractor can measure the actual airflow to the room and make corrections.

Whatever you do, don't try blocking ducts- it isn't the problem, and it won't work.

Your ductwork could be undersized, leaking, kinked, or just poorly designed ( not to plan), but this isn't a job for someone to do "off the cuff" or using guesstimates.

I would look for one of the providers on either the aps or srp websites that do the " energy-efficiency" tuneups, specifically "Nate" or "ashrae" certified contractors. I'd tell them that I was the one paying the bill, they need to "break out all their toys" to find and fix the problem, and that you need full written documentation of what they find and how they correct it to give to your attorney, in the event the builder doesn't step up.

[Steve Pickering]

I have lived in Arizona on and off for years. I don't recall ever having an air conditioner, except on the 5th wheels. That is full time, year-round, several years in a row.