My AC isn't cooling

[haas0311]

Got to give the back story first.... We moved in around mid May. Had a B-Day party for my son and we kept going in and out the back. Well the house to warm and it took almost a week for the house to cool back down. We called the home warranty people and they said that our unit is fine and that its the right size for our square footage but on the top end.. Well we tried closing the blinds, only leave through the garage now and if we have to open the back door, it is very quick. Still, can't keep it cool. We have our fans on full blast all the time and we can tell our AC is trying. My question is, would adding more insulation in the attic help? We had a guy come out and he said that we had insufficient insulation in the attic. Would it make that big of a difference? When I get home I plan on washing my unit outside. Any tips on keep a house cool is appreciated!!

[elliscountyhog]

Undersized it sounds like to me. This is the biggest reason why I love the all variable speed units. Use what you need and when you need it.

[T-roy66]

When you say you called the home warranty people are you saying they sent out a service company to look at your unit and check its operation? If so I would ask for their service report. This should include pressures and temperatures that your unit is running at. Should reference outside and inside coil condition. Did they inspect the supply and return ducts to make sure that your lines are not open in the attic. If they did not send a service company out to look at this type of items then you need to ask for a service company to come out and do a true service checkup on your system.

[Texas8point]

Got to give the back story first.... We moved in around mid May. Had a B-Day party for my son and we kept going in and out the back. Well the house to warm and it took almost a week for the house to cool back down. We called the home warranty people and they said that our unit is fine and that its the right size for our square footage but on the top end.. Well we tried closing the blinds, only leave through the garage now and if we have to open the back door, it is very quick. Still, can't keep it cool. We have our fans on full blast all the time and we can tell our AC is trying. My question is, would adding more insulation in the attic help? We had a guy come out and he said that we had insufficient insulation in the attic. Would it make that big of a difference? When I get home I plan on washing my unit outside. Any tips on keep a house cool is appreciated!!

YES. Insulation is huge. Fought that battle for 2 years and finally had 3 feet of non-collapsing cellulose insulation sprayed in...…. 1 day later AC unit shuts off and doesn't come back on until 9 or 10am. Cycles normally throughout the day now. House stays cool all the time.

[haas0311]

When you say you called the home warranty people are you saying they sent out a service company to look at your unit and check its operation? If so I would ask for their service report. This should include pressures and temperatures that your unit is running at. Should reference outside and inside coil condition. Did they inspect the supply and return ducts to make sure that your lines are not open in the attic. If they did not send a service company out to look at this type of items then you need to ask for a service company to come out and do a true service checkup on your system.

I honestly don’t know if this was done or not.. I will find out though!


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[haas0311]

YES. Insulation is huge. Fought that battle for 2 years and finally had 3 feet of non-collapsing cellulose insulation sprayed in...…. 1 day later AC unit shuts off and doesn't come back on until 9 or 10am. Cycles normally throughout the day now. House stays cool all the time.

You don’t know how happy this makes me! I will gladly spend the $2200 to make this happen


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[mikemorvan]

How old is the equipment? How old is the house? Single pane windows or Low-E double pane glass? There are many variables.

Insulation is huge. R-38 in attic is optimal.

[MossyRockRanch]

Had a similar issue and I had a duct that was open to the attic and three ac guys the wty company sent out never found.

[TexasBob]

Insulation will help, but I wouldn't start there given the severity. Something more than a lack of insulation is at play in my opinion. Google specs to see if tonnage is correct for your home. Point about open ducts is very valid. Start by checking temp out of the ducts in each room. Non contact thermometer makes this easy. You can google for the temp vs ambient split specs, but it will be cold air. Air temp and volume will give you an idea of your next steps. FWIW have seen a double wide with a large duct between halves that filled with condensation blocking almost all airflow. That was a headscratcher to diagnose. only found it when i bumped into the duct and it sounded like a water bed.

[buzzbait]

My buddy put a water sprinkler on his roof. His wife said the thermostat was set on 77 and she was cold in the house. Thats all I got

[topshot]

Check delta t to ensure unit is working properly, if you dont have appropriate temperature drop across the coils your unit needs attention. If you have a 20 degree delta t you should look at installing insulation in the attic to a value of R30 minimum...after that you need to start looking at the building envelope...windows, doors and wall insulation.

How old is the house and what type of windows are in it?

[TeamAmerica]

i would ask to see a report on the subcooling, superheat, temps they tested. Buy a $20 IR laser temp gun at harbor freight. check the temp on the air entering the supply return vent and compare to the temp on the conditioned air coming out the closest vent. you should be getting 20 degree split (just a good rule of thumb - not scientific). you should be blowing high 50s assuming your return air in the house is in the high 70s. if not, you may be low on refrigerant, losing air in the ducts, or a number of other issues.

with these warranty companies, you really need to hold their feet to the fire. might even need to pay a service call fee to get a independent HVAC company to diagnose and make recommendations. maybe you could reimbursed if you prove they failed to diagnose it.

[bowhntrmatt]

I would call a reputable company to give you a second opinion. Assuming the house isn’t brand new, I have a hard time believing that the family before you lived with that for years. Insulation won’t hurt, but I would make darn sure the system and ductwork are operating at peak performance before throwing money at insulation.

[HotRod Hunter]

Make sure the house has insulation. I once had a friend who moved into a new house in the winter and didn’t realize the house had no insulation until that next summer after I climbed up in her attic to see how much she had . I couldn’t believe there wasn’t any.

[Dr. Evil]

Temp coming out of your vents should be at least 30 degrees cooler than outdoor temp. If not, your a/c isn’t working properly.