AC unit not keeping up with the heat (sale, HOA)

[DetroitN8V]

I bought a two-story house despite a one-story being one of my must-haves. Everything else was perfect so I looked past it and convinced myself that the summer heat upstairs wouldn't be anything the AC unit couldn't fix. I'm beginning to regret caving on that item.

The downstairs AC unit seems to keep up without issue, however, the upstairs unit cannot get the temp below 82. Cold air blows out of the vents but it doesn't seem to be able to lower the temp any more than that. Could something be wrong with it or is it possible it's simply the wrong size to keep up with the demand? I need it nice and chilly to sleep. I wish I remembered to write down what brand/model it is but all I can tell you is it's old and seems fairly small. Anyone have this problem before? I'm hesitant to call an HVAC guy for fear that he'll simply try to sell me a new unit. Thanks in advance for any advice you can offer.

[Ponderosa]

When you say you have cold air out the vents you should be seeing it coming out at about 20 degrees cooler than it is going in. If it is, your unit is probably functioning fine. But, from the one two story I had you are going to have a long hot summer. Mine had a balcony area overlooking the living room. As air cooled upstairs it just spilled over the rail and down as the warmer air below rose. The AC upstairs ran non stop all summer. The only thing that worked, and it was not well, was to overcool the lower area which seemed to stop the circulation somewhat. It would be 70 downstairs and maybe 76-78 upstairs. If you turn up your lower unit to save bucks at night all you will be doing is moving the warm air up to the second floor. IOur BR was downstairs and we were cool to cold while the kids were sweating away upstairs.

[DetroitN8V]

Well that's not good news. I guess I foolishly thought that by setting it at say 74, it would end up at 74 eventually. I think I'll take your advice and drop the temp downstairs a bit to see what that does. Solar screens are also in my near future. I'm still wondering if a larger unit (more powerful, higher SEER rating?) would help, meaning mine may be undersized.

[Zippyman]

There's no way to know whats going on without checking airflow over the indoor coil & line pressures on the refrigerant, along with looking at the ductwork in the attic.. my home was built & operated for 20+ years with a fifteen-foot return line where three-feet would have sufficed.. the extra twelve feet of return duct was coiled on top of itself and kinked so it could have never flowed even 50% of the air that it should have.. so you could have a very old problem, like I did, or a newer problem like a torn or stomped duct, or an indoor coil plugged with hair & fuzz..

Its really easy to damage the flexi-duct in most attics - a cable guy, alarm guy, or even a home inspector could easily crush or tear a duct & either block the cold air off, or send a bunch of it into your attic, without even realizing they did it.

I think I already gave you my a/c guy's number, pm if you need it again.. he wont rip you off, and if he does, I'll help you give him an atomic wedgie. ;-)

The odds that your unit is undersized are extremely slim.. i've yet to see an undersized unit here.. too big by 50% is much more common..

[curly5759]

I feel your pain. I'm in a single story house with a fairly new A/C unit. Our first summer in the house, not only did the A/C not cool the house,the temperature actually increased during the afternoon.

APS offers a service where an A/C tech of your choice ( you choose from a list of providers) comes out and checks out your home for insulation efficency. They charge you $100, but you get way more for your money than you think. It is a kind of a loss leader for the contractor because they are hoping you will hire them to fix any problem found. It was a great deal for us. The tech that checked the house pressurized the ductwork to check for leaks and then pressurized the house to check it for leaks. The result was that we didn't have enough insulation in the rafters. I wound up having insulation blown in, the inside of the roof painted with a silver reflective paint and we also had the underside of the floor insulated (house sits on a crawl space)

We did this in the winter and the result was immediatly noticeable. The heater ran less often and the house stayed warmer. So far this summer, the A/C has been able to keep up with the outside heat. It will keep the house at what we set it to and it will cycle now.

Give APS a call and talk to them about them about the energy audit. Depending on what you do, there are some rebates available.

Curly

[R_Cowgirl]

• Solar screens are a must. That will cool the upstairs considerably

• Make sure the fans are turning in the right direction so the AC is cycled downwards - that means they should be turning counterclockwise. (There's a switch on most fans.)

• If you don't have fans yet, I'd consider putting them in all the upstairs rooms. They aren't that hard to install. Or get some of the Vornado fans and then you can move them around.

• You could also get a portable swamp cooler at Home Depot. They don't run all that much. Because the humidity is so low, the additional humidity and the fan across the wet vents helps to cool the house. I lived in Hawaii for a long time, though, so I like the extra humidity. That's a personal preference. You may not like it.

• If the attic area isn't vented, that will also help. When I added a couple of vents to my roof, it dropped the temp in the house by about 10 degrees and my AC unit didn't have to work too hard.

• If you have Home Appliance Insurance (I have American Home Shield), they may be able to get it fixed for you. Mine was hit by the hailstorm and my AHS coverage provided me with a replacement with a low deductible. Check to see if you have coverage on the AC unit. A lot of times that's part of the sale when you buy homes in the Valley. I also noticed my electric bill dropped considerably when I got a newer and more efficient unit.

• Spring for a visit from an AC guy. I swear by AZ Eddie's AC - Bob Eddy is a really good guy. He doesn't steer you wrong. When my AC stopped working a couple of years before the hailstorm got to it, he was the guy AHS sent. He was really good, didn't charge me for anything I didn't need, was fast and really professional. He only takes two days off a year: St. Paddy's Day and the opening day of baseball season. He has zero complaints on BBB even though he hasn't gone through their system. There's something to be said about that in the HVAC business.

[LBTRS]

You're trying to cool your upstairs to 74 in the heat we've been having? I think that is your first problem...during the week we cool ours to 80 during the day, 78 in the evening and 76 at night. Weekends 78 during day and evening and 76 at night.

Our two story with a large open area between upstairs and downstairs doesn't have to run constantly. I will say, when we were doing our walk through in July the builder turned the upstairs AC to 74 and it ran for three hours and would never get below 76 during the middle of the afternoon when it was 105 outside.

I think that asking a AC to get an upstairs to 74 when it's over 105 outside is expecting a bit much.

[stan4]

The unit can blow out 50 degree air, but the fact is you're unlikely to get the temp more than 20 degrees below what it is outside.
We have three 4 ton units which work pretty well until it's 110 outside...then there's an issue.
Do you have attic fan? Regular fans? Are you covering the windows? Make sure there are no leaks - check the weather stripping, etc. If there is an upstairs/downstairs issue, have one machine support the other by running both areas.

24 years of Texas a/c running all sorts of units (swamp coolers to old tranes to the newest high rating stuff...)...much can depend on what else you have going on.

[CheyDee]

Originally Posted by DetroitN8V

I bought a two-story house despite a one-story being one of my must-haves. Everything else was perfect so I looked past it and convinced myself that the summer heat upstairs wouldn't be anything the AC unit couldn't fix. I'm beginning to regret caving on that item.

The downstairs AC unit seems to keep up without issue, however, the upstairs unit cannot get the temp below 82. Cold air blows out of the vents but it doesn't seem to be able to lower the temp any more than that. Could something be wrong with it or is it possible it's simply the wrong size to keep up with the demand? I need it nice and chilly to sleep. I wish I remembered to write down what brand/model it is but all I can tell you is it's old and seems fairly small. Anyone have this problem before? I'm hesitant to call an HVAC guy for fear that he'll simply try to sell me a new unit. Thanks in advance for any advice you can offer.

We had this same issue when we lived in Texas. (We don't have it here because we learned our lesson about two story houses.) After going through all of the checks previous posters mentioned, the only thing which truly remedied the situation was throwing a window a/c unit in one of the master windows and turning it on at bedtime. We upped the thermostats on the central units when we turned the window unit on, because we didn't need them working so hard while the other was on too. That saved a little bit on the extra electricity we were using.

The problem with tossing in a window unit is many HOA's don't allow them, so if you're in a HOA this may not be a possibility for you.

[Ponderosa]

Originally Posted by CheyDee

We had this same issue when we lived in Texas. (We don't have it here because we learned our lesson about two story houses.) After going through all of the checks previous posters mentioned, the only thing which truly remedied the situation was throwing a window a/c unit in one of the master windows and turning it on at bedtime. We upped the thermostats on the central units when we turned the window unit on, because we didn't need them working so hard while the other was on too. That saved a little bit on the extra electricity we were using.

The problem with tossing in a window unit is many HOA's don't allow them, so if you're in a HOA this may not be a possibility for you.

You could use one of those portable styles they have now that do not need to hang in the window. The HOA would never know. 12000 btu should make icicles on your bed by morning!