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New House AC question
Posted on 8/10/23 at 9:09 am
Posted on 8/10/23 at 9:09 am
First summer in our new construction house and my units are having trouble keeping my bedrooms cold.
Kids bedrooms are on west side of the house and master is on the east. If I keep both units on 72 all day the kids bedrooms get up to 75-76 in late afternoon when sun is on that side. Unit is running almost 20 hours a day with thermostat on 72 at all times.
Mater side runs about 16 hours a day of left on 72.
South east Louisiana. AC company says units are charged up and clean.
Am I expecting too much out of a brand new house and AC in this heat thinking it should keep up?
Kids bedrooms are on west side of the house and master is on the east. If I keep both units on 72 all day the kids bedrooms get up to 75-76 in late afternoon when sun is on that side. Unit is running almost 20 hours a day with thermostat on 72 at all times.
Mater side runs about 16 hours a day of left on 72.
South east Louisiana. AC company says units are charged up and clean.
Am I expecting too much out of a brand new house and AC in this heat thinking it should keep up?
14
Posted on 8/10/23 at 9:11 am to Simon Gruber
Are the units undersized? What type of insulation?
Posted on 8/10/23 at 10:02 am to Simon Gruber
I am about to have my AC guy check my freon again. Mine are performing about like yours.
Posted on 8/10/23 at 10:11 am to Simon Gruber
Friend,
What is the outdoor temperature when your temperature rises to 76 indoors? Most A/C systems are designed for a delta temperature of 20-25 degrees. That means that if it is 100 degrees outside, your A/C is designed to keep your inside at 75-80 degrees.
That is why it is imperative for your units' health that you do not keep the thermostat at 72 if the temperature outside you are trying to reduce is 100. Running the system all day like you are reduces your A/C system's lifespan, will create large electricity bills, and is not good on the electrical grid.
It is not a popular opinion here, but set your thermostat higher. I would never recommend setting it at a greater than 20 degree difference from the outside temperature.
Yours,
TulaneLSU
What is the outdoor temperature when your temperature rises to 76 indoors? Most A/C systems are designed for a delta temperature of 20-25 degrees. That means that if it is 100 degrees outside, your A/C is designed to keep your inside at 75-80 degrees.
That is why it is imperative for your units' health that you do not keep the thermostat at 72 if the temperature outside you are trying to reduce is 100. Running the system all day like you are reduces your A/C system's lifespan, will create large electricity bills, and is not good on the electrical grid.
It is not a popular opinion here, but set your thermostat higher. I would never recommend setting it at a greater than 20 degree difference from the outside temperature.
Yours,
TulaneLSU
Posted on 8/10/23 at 10:22 am to Simon Gruber
quote:
75-76 in late afternoon
This is not abnormal on this heat, keep ceiling fans going at a higher rate in affected areas
TulaneLSU is correct on the expectations of AC units in this heat
Posted on 8/10/23 at 10:46 am to Simon Gruber
I replaced my units in my current house as soon as I moved in. I am getting very similar results as you during this wave. I really don't think what you're experiencing is abnormal.
Posted on 8/10/23 at 10:55 am to Simon Gruber
What's the thermostat showing for actual temp when the kids rooms are 75-76? Is it showing 72 for actual temp or is it above?
Also, how is it in other rooms served by the kids bedrooms unit? You could check the balancing dampers that serve each duct runout. Make sure they're fully open to the kids bedroom. If they are, you could try pinching back on dampers to areas that are comfortable. This would send more air to the kids rooms theoretically. You're still limited by duct size though. This can be tricky though, because different areas need more air at different times of day. Need plenty of air in the den for instance when everyone is awake vs when everyone is sleeping, etc. Usually its a happy medium.
One last thing. 6 tons for 2,600 sq ft. is fine. Its average for today's typical house. Its all about how well the house is insulated though. With how hot its been, the units very well just might not be able to keep up. One thing you you can do as more of an observational experiment to see how well your house is insulated is to turn off the a/c when its hot outside. The faster it warms up, the more heat is getting in.
Also, how is it in other rooms served by the kids bedrooms unit? You could check the balancing dampers that serve each duct runout. Make sure they're fully open to the kids bedroom. If they are, you could try pinching back on dampers to areas that are comfortable. This would send more air to the kids rooms theoretically. You're still limited by duct size though. This can be tricky though, because different areas need more air at different times of day. Need plenty of air in the den for instance when everyone is awake vs when everyone is sleeping, etc. Usually its a happy medium.
One last thing. 6 tons for 2,600 sq ft. is fine. Its average for today's typical house. Its all about how well the house is insulated though. With how hot its been, the units very well just might not be able to keep up. One thing you you can do as more of an observational experiment to see how well your house is insulated is to turn off the a/c when its hot outside. The faster it warms up, the more heat is getting in.
Posted on 8/10/23 at 11:09 am to Simon Gruber
I mean this in the nicest way possible but I wouldn't judge your unit based off 102 degree temps. 72 is way too low unless your house is perfectly insulated.
Posted on 8/10/23 at 2:05 pm to Simon Gruber
HVAC Design temperature for much of the Deep South is 92-94F, which means if your unit is properly sized it can maintain a set point temperature of 75 F at those outside temperatures. When temperatures are in the high 90s/low 100s, your temperature will likely creep above 75 F much of the afternoon early evening, much less maintain a temperature of 72 F. Though it sucks for this heat wave, the good news is that for the other 97% days of the year you are not going to have an oversized system, which would likely be problematic in terms of home comfort, operating expense, and HVAC operational life.
TL:TR - your units are very likely properly sized, according to manual J heat load calculations. Your HVAC company is shooting straight with you.
TL:TR - your units are very likely properly sized, according to manual J heat load calculations. Your HVAC company is shooting straight with you.
Posted on 8/10/23 at 2:34 pm to Simon Gruber
My AC guy just left. He added a little freon for a known leak that we will address this fall/winter.
He got up at 4 AM to install two new units. Times like these I'm glad I am not crawling in attics and just in an uncomfortable 76-78 degree home.
He said that many of his calls are checking units and telling people that they're at peak performance...peddling as fast as they can.
He got up at 4 AM to install two new units. Times like these I'm glad I am not crawling in attics and just in an uncomfortable 76-78 degree home.
He said that many of his calls are checking units and telling people that they're at peak performance...peddling as fast as they can.
Posted on 8/10/23 at 2:59 pm to Simon Gruber
I'm in a new construction as of the last few months.
2500sq ft, 1 level, 12ft ceiling, spray foam, single 3.5 ton unit, and in the heat of the day I could drop the entire house below 60 if I wanted to. I'm in Cen Texas where it's 105.
Maybe spray foam really is gods work, but I don't think you're expecting too much.
2500sq ft, 1 level, 12ft ceiling, spray foam, single 3.5 ton unit, and in the heat of the day I could drop the entire house below 60 if I wanted to. I'm in Cen Texas where it's 105.
Maybe spray foam really is gods work, but I don't think you're expecting too much.
This post was edited on 8/10/23 at 3:02 pm
Posted on 8/10/23 at 3:19 pm to Simon Gruber
Do like Mawmaw and Pawpaw used to do... foil up those windows and hang blankets from the doorways baw!
Posted on 8/10/23 at 3:58 pm to Simon Gruber
Keep this in mind…. Your AC was almost certainly sized for your home. It probably wasn’t sized for outside temp of 100F. Otherwise it would be too large to work efficiently 97% of the rest of the time.
Also in the grand scheme of things a builder isn’t going to save much money by purposely under sizing an AC. Price of poker is virtually the same.
Heat load is extremely high right now. That’s really the issue you have described and it is common in August.
You are fine in my opinion.
Also in the grand scheme of things a builder isn’t going to save much money by purposely under sizing an AC. Price of poker is virtually the same.
Heat load is extremely high right now. That’s really the issue you have described and it is common in August.
You are fine in my opinion.
This post was edited on 8/10/23 at 4:00 pm
Posted on 8/10/23 at 8:14 pm to Simon Gruber
Have a qualified professional pull a heat load first. In theory, you should have enough tonnage to cool but I’d double check. Second, have the duct work looked at. If you’re getting far cooler temps in the center of the house but struggling on the far reaches you could have shoddy duct work. (Happens more than you’d expect)
Posted on 8/12/23 at 8:16 pm to Simon Gruber
We just moved into a 2515 sq ft home built in 2022. 4 ton Amana. Had it serviced twice this summer. Thought we needed a 5 ton. Owner of A/C company said everything checked out fine, and that we would potentially have humidity problems with a 5 ton unit during October through April when it isn’t blazing hot because the unit would shut off more times than not.
During the past few weeks, we have our A/C set for 74 from 6am-8pm, then drop it to 69 at night. It maintains 74 pretty well if there isn’t too much in and out. Just takes a little long to reach 69 at night. Typically, it’s still 71 degrees at 10:30-11pm when I finally fall asleep.
He did notice that the fan was not set on High in the attic, which has helped since flipping on. Looking at planting some medium-sized trees in November to fell with outside shade.
During the past few weeks, we have our A/C set for 74 from 6am-8pm, then drop it to 69 at night. It maintains 74 pretty well if there isn’t too much in and out. Just takes a little long to reach 69 at night. Typically, it’s still 71 degrees at 10:30-11pm when I finally fall asleep.
He did notice that the fan was not set on High in the attic, which has helped since flipping on. Looking at planting some medium-sized trees in November to fell with outside shade.
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