Any Advice About Maximizing Air Conditioner Efficiency?

[Malibustyle23]

The obvious answer is not to have air conditioning at all. We debated on installing it but I would rather spend the money on Disney vacations. So no A/C for me.

Where do you live? AC is pretty much a necessity around here and I am in MD. I couldn't imagine in lower parts of the US. We also could not survive without a vehicle in our part of the state.

 

[Dakota731]

[AC is pretty much a necessity around here and I am in MD./QUOTE]
I thought that too then my mom reminded me that she and my dad slept in the attic with just a floor fan in our childhood home for twenty years. No central air then, so I agreed with her that we are spoiled but I'm grateful!!

 

[tvguy]

Yes there are many factors. We just had 2 new trane 4 ton units installed along with new air handlers (per code both compressor and air handler must be replaced at the same time). Getting quotes to hook up solar to them.

I would NOT want to pay the electric bill for that setup. House must be in the 4,000 square foot range

 

[Alexle2007]

We're in MD with a 4600 sq ft home with 2 zone heating. We keep our A/C set at 80 degrees on both floors but turn it off when the temperature drops. The 1st floor is definitely cooler than the 2nd fl. We had a "peak" day last week and the electric company asked us to conserve energy. We used 50 MHz compared to a friend with a house half the size of ours and they used 3 times the energy. We earned $0 despite the drastic difference. My electric bill is always less than $200 and about $130 in the summer.

 

[osopecoso]

I would NOT want to pay the electric bill for that setup. House must be in the 4,000 square foot range

It's not cheap but not bad. Our house is 4400 sf. We have a Mitsubishi package unit in our room. Our water heater, stove, dryer and pool heater are all on gas. Those help out with the electric. Waiting for the end of hurricane season for installing solar panels.

 

[osopecoso]

We're in MD with a 4600 sq ft home with 2 zone heating. We keep our A/C set at 80 degrees on both floors but turn it off when the temperature drops. The 1st floor is definitely cooler than the 2nd fl. We had a "peak" day last week and the electric company asked us to conserve energy. We used 50 MHz compared to a friend with a house half the size of ours and they used 3 times the energy. We earned $0 despite the drastic difference. My electric bill is always less than $200 and about $130 in the summer.

I would love that electric bill in the summer. In the winter it's about $200 and the summer it can hit close to $400 (July-sept). That's why we want solar panels. Neighbor had it installed on their home which is bigger than ours. Their bill is about 1/4 of what it used to be.

 

[tvguy]

It's not cheap but not bad. Our house is 4400 sf. We have a Mitsubishi package unit in our room. Our water heater, stove, dryer and pool heater are all on gas. Those help out with the electric. Waiting for the end of hurricane season for installing solar panels.

My wife's stepfather replaced a 2 ton unit with a 4 ton unit on an 1100 square foot house. It was light a hurricane when that thing turned on. And it didn't do a very good job of dehumidifying when it was humid because it just didn't run long enough to dry out the air.
But he was a bartender, and he was always swinging cash under the table, no permit deals with tradesmen who came into the bar.
He passed away before my MIL, and when she passed, we sold it under probate rules since my MIL never completed her estate planning. That meant, no disclosures, since DW had never owned the house, and hadn't lived it in in 20 years. That came in handy because the buyer wanted some items disclosed. We replied we had no idea and were not legally bound to disclose anything, and responded he should find the person who did the work. Oh, did I mention, HE had done the work. He immediately dropped the request.

 

[jedijill]

I live in Colorado and my house gets full sun and the upstairs gets hot! I installed a whole house attic fan this spring and in the first hot month I've saved $50 over the same period last year. I open a window and run the attic fan when I go to bed. The attic fan pulls the hot air out of the house and pulls in the cool night air. When I get up in the AM, I close the window and my A/C typically doesn't kick back on until later in the afternoon. So far the attic fan has been a great investment.

Jill in CO

 

[osopecoso]

My wife's stepfather replaced a 2 ton unit with a 4 ton unit on an 1100 square foot house. It was light a hurricane when that thing turned on. And it didn't do a very good job of dehumidifying when it was humid because it just didn't run long enough to dry out the air.
But he was a bartender, and he was always swinging cash under the table, no permit deals with tradesmen who came into the bar.
He passed away before my MIL, and when she passed, we sold it under probate rules since my MIL never completed her estate planning. That meant, no disclosures, since DW had never owned the house, and hadn't lived it in in 20 years. That came in handy because the buyer wanted some items disclosed. We replied we had no idea and were not legally bound to disclose anything, and responded he should find the person who did the work. Oh, did I mention, HE had done the work. He immediately dropped the request.

Who was the genius who advised he install a 4 ton on a 1100sf home. 2 ton would have been plenty.

 

[snoodledoo]

There is a guy on the radio who suggests super-cooling your home. In our area, we have on-peak and off-peak hours...if you don't have that, this method would not make sense. TLDR: you super-cool your house during the off-peak (lower cost) hours, so that you are using less a/c during the on-peak (high cost) time. http://www.azcentral.com/story/ente...ool-your-house-and-super-save-power/87321382/

 

[tvguy]

Who was the genius who advised he install a 4 ton on a 1100sf home. 2 ton would have been plenty.

His bar buddies.

 

[supersnoop]

Who was the genius who advised he install a 4 ton on a 1100sf home. 2 ton would have been plenty.

Square footage is irrelevant. You need to measur the volume (cubic feet) to properly size an a/c unit.

 

[wendow]

I live in Colorado and my house gets full sun and the upstairs gets hot! I installed a whole house attic fan this spring and in the first hot month I've saved $50 over the same period last year. I open a window and run the attic fan when I go to bed. The attic fan pulls the hot air out of the house and pulls in the cool night air. When I get up in the AM, I close the window and my A/C typically doesn't kick back on until later in the afternoon. So far the attic fan has been a great investment.

Jill in CO

I am in CO too and also have a 'whole house fan' or attic fan. It is fabulous for using the cool CO nights to cool the house off. However, a couple of my kids have pretty intense outdoor allergies. We found opening our windows and pulling in gobs of outdoor air was not a good deal for us We installed a high efficiency a/c two summers ago and our bill hardly rose ($15 month at most). We did, of course, have to pay for the unit which was $3100. I do suspect we will get that money back when we sell in a year or two. But I certainly agree, for the right person and climate, an attic fan is all that is needed.

 

[tvguy]

Who was the genius who advised he install a 4 ton on a 1100sf home. 2 ton would have been plenty.

My wife reminds me they had a 2 ton, it never did cool off the house. But, all the old school charts seem to indicate 2 ton would be appropriate. The newer charts seem to point to a 3 ton.
I just know I am not looking forward to replacing my heat pump that I put in 26 years ago. The AC guy that does my twice annual service says a new unit be more efficient, will likely cost me $10,000 with all the upgrades required by the building code. will last about 10 years, so the high cost will off set any energy savings.

 

[osopecoso]

My wife reminds me they had a 2 ton, it never did cool off the house. But, all the old school charts seem to indicate 2 ton would be appropriate. The newer charts seem to point to a 3 ton.
I just know I am not looking forward to replacing my heat pump that I put in 26 years ago. The AC guy that does my twice annual service says a new unit be more efficient, will likely cost me $10,000 with all the upgrades required by the building code. will last about 10 years, so the high cost will off set any energy savings.

Generally it's 500 sf give/take per ton. 2 2 ton unit today will cool off a lot quicker and be more efficient than a 2 ton unit from 10 years ago. Thankfully no need for a heat pump here. Did have a new gas pool heater installed last November which put us back $7k.

 

[ruadisneyfan2]

I agree, it depends where you live. But I'm in California too, in an area with a publicly owned and lower cost utility, where it is currently 100 degrees at 630 pm. I had one of those programmable thermostats to set different temperatures for different times of the day. My energy usage went up. The AC just worked too hard in the evening trying to cool the house off. It's the same idea that your refrigerator works on, a constant temperature uses less power.

That was the same with us. Now I only allow it drift up around 2-3 degrees warmer while we're at work. Then, instead of having it drop back down at 3:30-ish, I changed it to return to our evening temp at noon.
The prior way was making the ac work too hard at the peak of daytime heat.

 

[ruadisneyfan2]

My wife reminds me they had a 2 ton, it never did cool off the house. But, all the old school charts seem to indicate 2 ton would be appropriate. The newer charts seem to point to a 3 ton.
I just know I am not looking forward to replacing my heat pump that I put in 26 years ago. The AC guy that does my twice annual service says a new unit be more efficient, will likely cost me $10,000 with all the upgrades required by the building code. will last about 10 years, so the high cost will off set any energy savings.

The efficiency varies depending on the diameter of the ducts too. Our house that was built in the early 60's had just 4" ducts. We could have had a 10 ton unit and it would only be able to cool our house so much. Cool air is heavier than hot air so the fan has to work harder to move the air. Combined with narrow ducts just doesn't work well. Like an asthmatic trying to breathe. This is all from my brother who installed our old unit 20 yrs ago when we first bought our house.
When a tree fell on our house last year and smooshed our furnace and AC unit, the contractor installed a new unit in the attic and ran new main trunk the length of our house with 8" ducts and it's super efficient.

 

[tvguy]

The efficiency varies depending on the diameter of the ducts too. Our house that was built in the early 60's had just 4" ducts. We could have had a 10 ton unit and it would only be able to cool our house so much. Cool air is heavier than hot air so the fan has to work harder to move the air. Combined with narrow ducts just doesn't work well. Like an asthmatic trying to breathe. This is all from my brother who installed our old unit 20 yrs ago when we first bought our house.
When a tree fell on our house last year and smooshed our furnace and AC unit, the contractor installed a new unit in the attic and ran new main trunk the length of our house with 8" ducts and it's super efficient.

I have no idea what diameter ducting I have. I just know the laws are pretty strict here on what you have to do when you replace HVAC. Pretty much you have to replace all ducting with super insulated ducts and then they have to leak test the installation..

 

[ajwolfe]

In our experience, we spend less when we leave the temperature consistent. We've been experiencing around 90-100 temperature days the last few weeks so no a/c would not be an option for us.

 

[sk!mom]

In our experience, leaving it at one temp is better than turning it up and down. The biggest assist in keeping us cool and the cost down in our super sunny hot location is ceiling fans in every room except the bathrooms. The fans are only on if the room is occupied.