Any Advice About Maximizing Air Conditioner Efficiency?

[amcnj]

Hi. Does anyone have some real world experience in using central air conditioning efficiently? Some maintain that leaving it at one set temp is best, others that raising the temp if no one is home during the day is best. If raising the temp does have a benefit, is there a number of degrees above which it no longer is a net positive? What about for vacation time, do you turn the air temp up (again by how many degrees) or turn it off altogether?

Just curious if anyone has experimented and found a preferred way to go.

Thanks!

 

[runwad]

I don't have any real world experience but all I know is to make sure your furnace filters are cleaned as that impacts efficiency.

I find that we keep our house at 72 during the day and then drop it to 70 at night and I turn my fan on on the furnace at night to keep the air moving. We live in a split and that just helps to keep the air moving and the upstairs feeling cooler.

I turn the air off if the night time temp is 65 of lower because that is cooler than my air. I don't prescribe to leaving my air on all summer long. I need to air out my house, I think the upstairs gets so stuffy smelling with the air on for long periods of time. Can't wait to turn it off again, its been on for a week, ugh.

 

[tvguy]

We started keeping our house at one temperature a few years back, and it seems to have lowered our energy bills.
We used to have it either off or at a higher or lower temp during the day when we aren't home. But we have solar panels now, so if the ac or heater is running during the day when the panels are producing power, that costs less, and runs less when the sun is down and we are using power from the electric company.,

 

[Judique]

We started keeping our house at one temperature a few years back, and it seems to have lowered our energy bills.
We used to have it either off or at a higher or lower temp during the day when we aren't home. But we have solar panels now, so if the ac or heater is running during the day when the panels are producing power, that costs less, and runs less when the sun is down and we are using power from the electric company.,

Are these your own solar panels? Or one of the companies such as Solar City?

 

[amcnj]

Thanks for the responses. I have been keeping it at a constant temperature this year, but between getting a new system a couple years ago and the variations in weather from year to year, it is hard to determine if this way has any benefit over raising the temp when no one will be at home for hours.

 

[tvguy]

Are these your own solar panels? Or one of the companies such as Solar City?

Solar City. I have a Power Purchase Agreement with them, so no, I do not own them. Although Solar City sells their systems too, I had that option. And I will again in 3 years when the system is 5 years old. I was reading in the paper that Solar City is moving away from PPAs and to just selling the systems. They make more financing them than sell you the power.

 

[Judique]

Solar City. I have a Power Purchase Agreement with them, so no, I do not own them. Although Solar City sells their systems too, I had that option. And I will again in 3 years when the system is 5 years old. I was reading in the paper that Solar City is moving away from PPAs and to just selling the systems. They make more financing them than sell you the power.

My next door neighbor claims he pays no bill since his panels went up. He has a different company and I would have to go outside and peer at his equipment to remember the name. But he doesn't own the panels - he has a similar agreement to what Solar City gives.

Solar city is all over this area.

 

[Where'sPiglet?]

I have an attic fan. It kicks on automatically on really hot days. It draws the hot air up and out of the attic. This keeps the temperature in the house from getting too hot from heat from the attic, which in turn allows the a.c. to work more efficiently.

 

[tvguy]

My next door neighbor claims he pays no bill since his panels went up. He has a different company and I would have to go outside and peer at his equipment to remember the name. But he doesn't own the panels - he has a similar agreement to what Solar City gives.

Solar city is all over this area.

I think you neighbor is saying he has no bill from his electric provider. With solar panels, every company basically gives you two options. Buy all the power your panels produce at an agreed to rate, and sell excess power back to your utility. Or buy the panels and get all the power for free and sell excess power back to your electric provider.
Now, there are months that I make more electricity than I use, so I have no charge for electricity. However, my electric provider charges $20 a month just for being hooked into their system. I might sell them power worth more than $20 in those months, but they only settle my account once a year. So I always will have a bill of at least $20 from my provider. They estimate how much my system is producing, but they only balance the books once a year. So they will either owe me money, or I will owe them money, depending on how accurate their estimates are.
And of course, since I don't own my panels, I do get a bill from Solar City every month for ALL the power my panels generate, whether I use it, or if I resell it to my utility. My overall cost for electricity is about $25 a month lower than before. So worth it to have a PPA in my opinion. But not enough of a savings to justify the $37,000 (before tax credits) my system would have cost me to buy outright.

 

[gottalovepluto]

Hi. Does anyone have some real world experience in using central air conditioning efficiently? Some maintain that leaving it at one set temp is best, others that raising the temp if no one is home during the day is best. If raising the temp does have a benefit, is there a number of degrees above which it no longer is a net positive? What about for vacation time, do you turn the air temp up (again by how many degrees) or turn it off altogether?

Just curious if anyone has experimented and found a preferred way to go.

Thanks!

I take you're not dealing with extreme temps? Stable temp would be a disastrous approach where I live! Just in case you ARE talking about really hot... I'm in CA, 100+ degree heat, electricity is very expensive, haven't gone the solar panel route yet. The idea of keeping the AC at a stable temperature is ridiculous, I could never afford that. (Also 70? 72? Lol.) We keep the house at 85 when not there, 78-82 when home depending how rich we feel. We learned the hard way not to turn the AC off when we leave because stuff in your house gets destroyed. (Melted lipstick, weirdest was the melted gold colored design on a fancy blouse that was in a laundry bag in our closet once...)

So, the best approach is very dependent on where you live Solar may or may not be a good option but be careful to evaluate it thoroughly for your own needs and make sure you understand the financing aspect if you finance it.

 

[Albort]

My next door neighbor claims he pays no bill since his panels went up. He has a different company and I would have to go outside and peer at his equipment to remember the name. But he doesn't own the panels - he has a similar agreement to what Solar City gives.

Solar city is all over this area.

i did quite an extensive research on solar panel because i had considered doing it. With a pool pump my electric bill is always over $300-$400 in the summer. Yes, he might not be paying a bill, but you should ask him how much he is paying per month. This is where it might be good, might be bad. You basically play electric at a flat rate. So if the cost of the system is $200 a month, u pay $200 a month. Even if its cold and you dont use that much power, you still pay $200 a month. The good thing the power company sometimes will take back what you power in extra and credit you for times when u actually need it. So if you have a lot of credit saved up, using your AC at full power every day wont harm you must. The other thing about paying a flat rate is that you dont pay for any price increases the electrical company put on.

Theres another agreement where the solar company becomes your power company. You pay a lower fee but this is probably the worst plan.

Now, buying the system outright is the way to go. Way cheaper. we did the math for this, a 6kwh system was like $200 a month for 20 years with the solar company... we found out we could do as little as 9 years paying $200 a month to pay off our own system. we borrow from a line of credit so not much interest.

 

[tvguy]

i did quite an extensive research on solar panel because i had considered doing it. With a pool pump my electric bill is always over $300-$400 in the summer. Yes, he might not be paying a bill, but you should ask him how much he is paying per month. This is where it might be good, might be bad. You basically play electric at a flat rate. So if the cost of the system is $200 a month, u pay $200 a month. Even if its cold and you dont use that much power, you still pay $200 a month. The good thing the power company sometimes will take back what you power in extra and credit you for times when u actually need it. So if you have a lot of credit saved up, using your AC at full power every day wont harm you must. The other thing about paying a flat rate is that you dont pay for any price increases the electrical company put on.

Theres another agreement where the solar company becomes your power company. You pay a lower fee but this is probably the worst plan.

Now, buying the system outright is the way to go. Way cheaper. we did the math for this, a 6kwh system was like $200 a month for 20 years with the solar company... we found out we could do as little as 9 years paying $200 a month to pay off our own system. we borrow from a line of credit so not much interest.

Buying just didn't make sense to us. But electricity is relatively inexpensive here. My highest months aren't $200 for electricity and solar combined. That MAY be why they are pushing buying the system over PPA's now, because they make more selling the system to you and financing it than doing a PPA.

 

[Dakota731]

Someone told me your house is cooler and bills lower if you keep fan on all the time instead of auto. Is this true?

 

[Albort]

Buying just didn't make sense to us. But electricity is reatively inexpensive here. My highest months aren't $200 for electricity and solar combined. That MAY be why they are pushing buying the system over PPA's now, because they make more selling the system to you and financing it than doing a PPA.

they push for PPA because they also make money from kickbacks from the government.

 

[tvguy]

they push for PPA because they also make money from kickbacks from the government.

Yes, but apparently they make more by selling the systems and handling the financing themselves.

 

[Albort]

Yes, but apparently they make more by selling the systems and handling the financing themselves.

do they? here, If you get SunPower brand solar panel, they financier is Total. I think they set aside 3 billion just for solar... what im told is that they just apply for you and then u pay to them basically. the solar company doesnt do anything else unless there is an issue or maintenance work. im sure SolarCity is probably backed by Tesla haha.

 

[tvguy]

do they? here, If you get SunPower brand solar panel, they financier is Total. I think they set aside 3 billion just for solar... what im told is that they just apply for you and then u pay to them basically. the solar company doesnt do anything else unless there is an issue or maintenance work. im sure SolarCity is probably backed by Tesla haha.

Solar City makes it's money two ways. If you have a PPA, they making money selling your system to investors who want the tax credit. Or by financing the purchase.
Solar City and Tesla are the same company, they merged last year.
https://www.geekwire.com/2016/official-solarcity-tesla-merger/

 

[runwad]

Someone told me your house is cooler and bills lower if you keep fan on all the time instead of auto. Is this true?

I honestly don't know? But I remember my mom telling me don't let them fool you, your fan uses electricity to run.

I only turn my fan on at night because the air doesn't seem to kick on as much at night with the lower temps and no sun, so it gets stuffy upstairs. I can't say I'm noticing any more of an uptick in my bill having run the fan at night when the air is on. It is definitely cooler!!

 

[osopecoso]

Hi. Does anyone have some real world experience in using central air conditioning efficiently? Some maintain that leaving it at one set temp is best, others that raising the temp if no one is home during the day is best. If raising the temp does have a benefit, is there a number of degrees above which it no longer is a net positive? What about for vacation time, do you turn the air temp up (again by how many degrees) or turn it off altogether?

Just curious if anyone has experimented and found a preferred way to go.

Thanks!

Really depends on where you live. We are in north Miami. What we do is change the filter on a monthly basis, keep the drain lines clear (a backed up drain line can cause a lot of damage), a lot of insulation in the attic (FPL has an agreement with insulation companies where they will come out and spray insulation into the attic), and do not keep your temp the same all day. We have 2 ac on our home. Both are on nest's. it is programmed to fluctuate the temp all day. House never feels hot. We drop the temp in the bedrooms at night and raise it in the rest of the home.

 

[tvguy]

I take you're not dealing with extreme temps? Stable temp would be a disastrous approach where I live! Just in case you ARE talking about really hot... I'm in CA, 100+ degree heat, electricity is very expensive, haven't gone the solar panel route yet. The idea of keeping the AC at a stable temperature is ridiculous, I could never afford that. (Also 70? 72? Lol.) We keep the house at 85 when not there, 78-82 when home depending how rich we feel. We learned the hard way not to turn the AC off when we leave because stuff in your house gets destroyed. (Melted lipstick, weirdest was the melted gold colored design on a fancy blouse that was in a laundry bag in our closet once...)

So, the best approach is very dependent on where you live Solar may or may not be a good option but be careful to evaluate it thoroughly for your own needs and make sure you understand the financing aspect if you finance it.

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.