I've been turning the heat pump thermostats to warmer temps alternately between upstairs and downstairs when people are on one floor or the other during sleeping upstairs versus being downstairs during the day and evening, with the idea of saving on the electricity bill during the hottest parts of the summer.

My problem is there are two women in the house, one older and one very much younger, and they're both complaining loudly about the hot temps in the house driving them crazy. It's not like I'm not cooling things down when they're upstairs vs downstairs, it's just that their internal biology is quite different than mine, being women, aka they're always hot.

My wife told me her girlfriends' homes are always set to cool temps both upstairs and downstairs and they don't change the temps of floors and rooms depending on occupancy, and that by changing the temps all the time it actually wastes more electricity than it saves by just leaving them set to the same value 24x7.

So what is the truth about electricity use of either strategy ? Does it make enough difference for me to reconsider my strategy ? I need to investigate this issue to avoid any early assassination attempts on my life.

So what is the truth about any differences in electricity use for modern air-to-air heat pumps in the mid-Atlantic regions during the hottest parts of the summer ? If it doesn't make THAT much difference I may be able to conceded, but if the difference in cost is HUGE, I may need to hire a bodyguard.

What say you guys ? I'm not having much luck with internet searches.

But since you have two women, uncomfortable, hot flashes with access to knives, and you wish to sleep, well, make them comfortable would seem to be a high priority item.

We run a Nest thermostat, during the weekdays when nobody is home it is set automatically to the away setting which increases the AC temp of the main part of the house.

Supposedly this helps reduce run time and thus electricity use, but I can't really quantify it without changing that routine and seeing if a bill is higher, and that there are other variables that effect the bill such as refrigerator, dryer, pool pump etc.

Part of me says you really don't save much $ over leaving it at a reasonable temp during the day. IE instead of raising the start temp to 82, just leave it at 78 to maintain if say 78 is the target cool temp.

I have suspicions but no facts. If I were you, I would pick a time when temps are steady. Run it your way and monitor your power meter (mine is digital so I can see how much I am using. Do that for 24-48 hours then try the other way.

You cannot duplicate the conditions exactly, but you should be able to get it close enough to see which uses more power.

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Originally posted by mrvmax:
I have suspicions but no facts. If I were you, I would pick a time when temps are steady. Run it your way and monitor your power meter (mine is digital so I can see how much I am using. Do that for 24-48 hours then try the other way.

You cannot duplicate the conditions exactly, but you should be able to get it close enough to see which uses more power.

Unfortunately I can't experiment, the two female units would not stand for it. But I'm pretty sure a long time ago in this house, one year my summer bill was $950 for one month in particular, though I think the reason was one of my units was on the blink and I didn't know it.

quote:

Originally posted by HRK:
But since you have two women, uncomfortable, hot flashes with access to knives, and you wish to sleep, well, make them comfortable would seem to be a high priority item.

We run a Nest thermostat, during the weekdays when nobody is home it is set automatically to the away setting which increases the AC temp of the main part of the house.

Supposedly this helps reduce run time and thus electricity use, but I can't really quantify it without changing that routine and seeing if a bill is higher, and that there are other variables that effect the bill such as refrigerator, dryer, pool pump etc.

Part of me says you really don't save much $ over leaving it at a reasonable temp during the day. IE instead of raising the start temp to 82, just leave it at 78 to maintain if say 78 is the target cool temp.

Good point about paying to keep the women comfortable, and I suppose I could do that, but when it's 95 outside, sun bearing down on a large multi-faceted hip roof, and they want it left on 74 both upstairs and downstairs 24x7 whether they are home or away, I'm thinking that could be expensive. Part of the problem may be just me, since I still pay all of the bills for the house as I always have, and inflation and prices have outstripped my salary which peaked out some years ago, and cost of living increases never seem to keep up with inflation, yadda yadda, now I'm just rambling since we all have that problem.

There is a lot of dynamics happening here.
Should take in consideration the load on the system by allowing the space temp to increase and attempting to cool off with a warmer space and depending on time of day, high outside temps. ( higher load = higher wattage )
Only true way to know is to monitor the system watts ( KW meter ) as mentioned earlier.
I suggest that you stay with a comfort setting and not make changes unless away for some time or on vacation. Typically any savings realized is lost when cooling down the space. This is obvious for the winter months if aux heat is energized on recovery ( if thermostat allows such ). Newer systems are better at this and will not allow this to occur if the recovery rate is acceptable.
In short, keep the settings to the preferred comfort settings.
I do believe the complaints outweigh any possible energy savings.
One other thing is what is the space humidity? This is a major factor for comfort. In order to remove the humidity, the cooling must be on ( indoor coil below dew point ). There is multiple factors influencing this, such as the actual run time. Lower humidity allows a higher space temperature comfort level.

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Part of the problem may be just me, since I still pay all of the bills for the house as I always have, and inflation and prices have outstripped my salary which peaked out some years ago, and cost of living increases never seem to keep up with inflation, yadda yadda, now I'm just rambling since we all have that problem.

Valid points all, I've put in extra ceiling insulation, replaced all bulbs with LEDs, replaced a 30 year old garage fridge with a new efficent unit, electric stove is now gas, changed billing program to one with reduced costs for items run after 9pm, and timed the pool to run only after 9 on weekdays, and it's all I can do to maintain the total costs.

Seems for every power $ you try to save they increase the cost of power by $+X and all you can do is try to mitigate the increase.

If solar wasn't so stupid expensive I'd install it, might even put in a solar on lease since at that point we'd lock power costs per month and be off the constant power cost increase road.

"How much will you pay, to make misery go away?"

I think you might have to stop moving the temps up in the hope of saving a few dollars.
When I had two systems in my 2-story home the 1st floor unit seldom ran in the summer. The top floor unit ran keeping it comfortable, and what cool air fell down the stairs was enough to keep the first floor just as comfortable. I did not fluctuate temps other than setting both 1 degree cooler at night. I don't think varying temps up and down saves much other than when gone for a couple days or longer.
We ran ceiling fans in any room we used.

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Originally posted by wrightd:
I've been turning the heat pump thermostats to warmer temps alternately between upstairs and downstairs when people are on one floor or the other during sleeping upstairs versus being downstairs during the day and evening, with the idea of saving on the electricity bill during the hottest parts of the summer.

I have to wonder how much benefit you get from this. Are you able to separate the parts of the house with a door or something like that?

If not, I would expect at night the warmer air downstairs would just rise upstairs.

I'm not sure allowing the temperature to rise upstairs during the day just to cool it down at night is such a good idea. You still have to pull all that heat out.

Is the air able to circulate through the entire house? Or, do people want to keep doors closed when they are in certain rooms?

Realize that you only have to cool down one woman to make 99% of the complaining go away. For some reason men are not given to understand, a woman's discomfort is greatly magnified by another's nearby. Men, in contrast, when they see another man suffering are usually thankful, "at least I'm not that poor bastard!"

Do what I (we) did. Purchase a mini-split (12,000 btu/one ton) and put it in the room they spend the most time in. We did this for my wife and she kept that room 6 to 7 degrees cooler than the rest of the house. When she was not in that room we set the unit two degrees lower than the central to “help” the central system because the seer level on most mini-splits is above 20 (I think ours is 24). Solved two problems for just over $1500.00. Gave her a “cold room” for when she needed it and it also helped our main unit run less allowing the temp to be lowered by 1 or 2 degrees.

As for our second floor, since no one sleeps or goes up there unless the grandkids are coming over, we set it up on a Nest thermostat that she controls from anywhere at anytime. It usually is set on 77 to keep the humidity levels in manageable ranges.

Me too on the mini split in mama's main hangout. House stays at 73 and I wear a sweatshirt in peaceful silence.

We really need more info on the layout of your house and the specs on your heat pumps but as a generalization here’s some comments.

Generally speaking, it takes less energy to keep an area at a constant temperature then to constantly raise and lower it, although small changes like a degree or two sometimes works.

You mentioned that you installed more insulation in your attic. You should have R-50 up there. Also, since you live in Fl you probably have the upstairs unit in the attic which unfortunately is the worse place to place it. But you can’t do anything about that unless you make the attic an enclosed space.

How is the humidity in your home? Keeping the humidity at between 45 and 50% will improve how your house feels.

Finally, do you have any ceiling fans? These help tremendously, at least with the females in our home…

I think constantly changing the thermostat depending on when one person is on one floor and then another is pretty ridiculous and doubtful it's even saving any energy doing it for a few hours here or there. It takes less energy to maintain a constant temperature than it does to keep bringing the temperature down a few degrees and letting it climb up a few degrees. If you're worried about your electric bill, have more attic insulation blown in, that will pay for itself in less than 6 months.

In my experience, it's more energy efficient to leave the thermostat within a couple of degrees at all times.

Here in Lower Alabama, close to the Florida line, it gets hot in the summer. I keep my thermostat set at 79 day and night.

That's a little higher than what I would be most comfortable at. The way I've been able to not only tolerate 79 but actually been comfortable and enjoy it, is with the use of fans.

I use a 16in pedestal fan in the living room and the oscillating action covers two other rooms. In the bedroom, I have a table fan at night.

The fans I have are quiet and the white noise actually helps me sleep better.

The pedestal fan I selected is almost what a nice ceiling fan would cost ... except a ceiling fan isn't portable.

If you do want to go a fan route, chose one with a DC motor. Not only are they more energy efficient, but usually quieter.

These are the two fans I have and would recommend. The Amazon Basic pedestal fan is currently out of stock though ...
https://www.amazon.com/dp/B07B...product_details&th=1
https://www.amazon.com/dp/B0BS...product_details&th=1

There's a ton of variables, house size, location, shade, climate, HVAC system type, just to name a few. I found that for my house, unless I can leave it at a +5* setting for at least 8hrs at a time, I'm using more energy to cool it back down vs leaving it at 73 full time. There are a ton of scenarios where that's not true, but the savings were miniscule at best.
This was for single-stage AC based on runtime & a fixed kW-hr per minute, the winter setting was harder to calculate & I just said to hell with setting up a schedule (plus my wife was stopping at home 2-3 times per day due to her schedule).

Plus, the cost of listening to bitching all the time is extremely high.