How many hours per day do you think your home cooling system runs in the dog days of summer? Mine is going to run all day unless I raise the temperature setting on my thermostat.I read somewhere that your cooling system should be able to maintain a 20 degree differential from the outside temperature...mine won't do that even if it runs all day.

My house is sealed off pretty good...I do have black shingles on the roof with a ridge vent. I'm considering a lighter color next time which won't be much longer.

I have a wifi thermostat so I can monitor the house during the day...I can also raise and lower the temp from my cell phone while I'm at work. I just don't want it running all a day and at the same time, keep it comfortable for my pets.

I have a GEO Thermal system and I keep it at 74. In our last house my wife was dying at anything over 72. It probably runs 20 minutes per hour or so.

Maybe things aren't as bad as I'm thinking. I just checked my kWh usage from last summer...

June: 894 - Average Daily Usage 30

July: 1210 - Average Daily Usage 40

August: 1140 - Average Daily Usage 37

I'm cooling a 3000 square foot 2 story house.

I'm outside Charlotte. Mine is basically running all day. I have it set at 77 and it maintains 77 till about 4 pm then gets up to 79-80 for about 3 hours then back down to set point. Will be interesting to see what happens in the next few days when predicted temps are 95-97.

Don't know if I have a problem or it just ain't designed to handle this temp and humidity. House and unit are only 2.5 years old.

Doesn't answer your question directly, but you might need more attic insulation and more soffit and roof vents to vent out the hot air. Disregarding the black shingles, I think the attic should not be hotter than maybe 18-20 degrees than the outside ambient temp.

Knowing your attic temp would be very helpful.

Lots of soffit vents to bring in air to the attic and a electric power roof vent, or 2 or 3, on a thermostat will work wonders.


Good luck to you.

We keep it at 74. Has been mid 90s the last week and the AC keeps up fine. It kept up with 100S in years past. You might need a larger unit.

When our attic exhaust fan died last summer I noticed our a/c struggled to keep up. You might want to consider an attic exhaust fan.

When was the last time you had it checked/serviced?

Air filter clean? What size, brand and merv do you use?
After it runs 10-15 mins, does the large copper line outside sweat?

Hard to tell from this end, but it might be running at peak efficiency and be to small. Or it could be low on airflow/refrigerate and be operating at a lower capacity.

When a unit is properly sized, it should be running most of the time when the temperature outside is at the normal high.

Personally, I'd go somewhere else to figure this out. It's easily more complicated than just the setting. Running more of the time might not be a bad thing because it's removing humidity when it's doing that. But it could also be that you're losing refrigerant if it isn't keeping up. Venting the attic, especially with a powered ventilator, is an old school approach. If your house is well sealed and insulated (separate issues unless you have spray foam), it probably doesn't make a big impact. If not, you easily could be pulling air between conditioned and unconditioned spaces and that could be worse. Then there's the question of whether the ducts are in the conditioned envelope.

And if it's doing it's thing and doesn't cost too much don't worry about it.

Ours is set to 76 but goes to 81 during the day, when we're at work. Used to be set for 78 but window and insulation improvements have made that not as good for humidity control unless it's stupid hot out.

Save energy when you leave and set it at 78-81 or so. Then have turn it down to normal on the way home.

Missouri is always hot in the summer. We keep our thermostat set at 77.

My main floor thermostat sends its data to the manufacturer who then e-mails it to me once a month.

2,000 square foot first floor of a story and a half. Last year the average May high/low temperature was 76/55. Heat was set to 67 away, 69 home. AC was set to 78. 15 hours of heat, 3 hours of A/C, 726 hours off.

This year the average high/low was 84/63. Due to the high humidity we lowered the A/C to 77 away, 74 home. 0 hours of heat, 54 hours of A/C, 690 hours off.

That's an average of just over 100 minutes each 24 hour day. So far it is substantially warmer than it was last month. I suspect the A/C is running 10 minutes at a time.

I get a weekly email from the power company (I have a smart meter) that graphs kw vs time of day.

We’ve been running ~100 for the last 5 or 6 weeks. I have 2 AC units so the peak is higher with both running at the same time. I keep my home 73 24 hours a day to keep humidity down.

Houston area. Keep my thermostat at 77 during the day with ceiling fans going. At night, it goes down to 74 and the ceiling fan in my b/r...sleep with a sheet only.

quote:

Originally posted by bubbatime:
Save energy when you leave and set it at 78-81 or so. Then have turn it down to normal on the way home.

This would be bad advice for anyone who has a system which fails to keep up with a current thermostat setting.

Same thing goes for when the weather is at peak hi/low temps, set the thermostat and let it be.

I’m in Texas, so it’s quite hot. Lots of days in the upper 90s. I keep it 77 during the day, but turn it down to 64 when I go to bed. Zero problems out of the HVAC system in the 10 years I’ve owned the home.

I have it set at 76 and told the kids not to touch it.

During winter it stays at 68.

Mine stays at 70 all year.

flashguy

Southeast Viginia. Most summer days are in the high 80s to low 90s with some days into the 90s and 100s. Humidity is always very high.

I have a two story house with a loft 2nd living room over the main part of the house. Also, two bedrooms upstairs, and the main bedroom downstairs. I have a ceiling fans upstairs and down.

I keep my central air's thermostat at 75. I supplement the upstairs bedrooms in the dog-days of summer with LG brand portable ACs. Somes in the loft as well. The central AC keeps the downstairs nice and cool but the loft gets warm and the portable ACs realy help take the burden off the central. I leave them off in the bedrooms when no one is using them. I keep the loft portable AC set at 78. I have actually saved quite a bit becase the portable ACs don't run that much, and the central nohwere near as much as it did before I have the protables. Mt wife would turn the central thrmostat down when she went upstairs becasue upstairs was always warmer than downstairs. With the portables in use a few months during the worst of the summer, she never touches the thermostat.

70°F. I don't give a shit how expensive it is, I want to be comfortable when I come inside.