I continue to be a bit obsessed with learning about air conditioning, since our central air unit went out in our vacation place in Florida last week. We’re back home in Minnesota now, and have had a few hot days here, too.
Our air conditioning is happily chugging along, set at about 72° – day and night. I know people who keep it much warmer in the summer (~78°), but that’s much to0 warm for us … and most people according to this research …
It looks like people sleep better, work more productively, and learn better when indoor temperatures are kept about 73° or better.
This comes at a cost, of course, but we live in a relatively affordable energy state(s). Minnesota and Florida rank #22 and #23 for energy affordability, respectively. The average monthly electricity / natural gas bill here is a little less than $200. California & Connecticut – two of the higher priced states – are more than double that!
My estimate would be that our air conditioning “on” at 72° vs 78° comes at a cost of about +$2/day. That’s a rough estimate – but in the ballpark. I’ll gladly skip a Starbucks for that! What temperature do you keep your thermostat at in the summer?
Image: Pixabay
MrFireStation 
I set my programmable thermostats to 74 degrees F in the occupied areas during most of the day. For the high rate peak time between 4:00 PM and 9:00 PM, the thermostats programs are set at 76 degrees F. At bedtime, my bedrooms drop to 69 degrees F. During the day, the unoccupied bedrooms are programmed to 80 degrees F.
I checked my average monthly electric bills going back to 2021 and the cost was around $254.43 per month. This year I am running around $324.58. I did change the programming in my thermostats to drop the bedroom temperature from 71 to 69 degrees F to sleep better. I was not aware of the sleep study that you displayed on the top left, which looks like 67 – 68 degrees is the best setting.
Are your $200 monthly bills including both natural gas and electric? If you did, then I would tack another $60 per month for propane for tankless hot water heater to my electric cost to have an apples to apples comparison with your numbers
A better way to compare electric rates is the cost per KWH. I just got my mid June to July bill and the cost was $365.14 for 1097 KWH, which works out to an average of 33.3 cents per KWH. My billing is Time of Use, so peak use times between 4:00 PM and 9:00 PM cost 54.6 cents per KWH. Non-peak cost is still a very high 26.3 cents per KWH. This peak use pricing is one of the wonders of green AKA occasional energy. You get home from work and want to crank up the AC that has been set back all day, cook dinner on your electric stove, turn on some lights and watch television. But, the solar cells are not producing cheap electricity, so they gouge you.
I live near the coast so my temperatures are moderated by the Pacific Ocean. I installed a very high efficiency Heat Pump two years ago that dropped my electric draw when I am air conditioning or heating by 38%. My house is setup with four zones to match heating and air conditioning to occupancy. Zoning improves comfort and reduces electric at the same time. There are less well off people living in inland hotter climates in smaller homes and they have electric bills that are over $1,000 per month probably for fewer KWH than you are using. They visit Walmart during the day to cool off as a respite from the heat.
Here is an article about what is going on in the People’s Republic of California in terms of electric cost and its impact on air conditioning by Victor Davis Hanson. https://www.onepoliticalplaza.com/t-356713-1.html
We have been having a nice online conversation about HVAC thermodynamics and the economic concept of diminishing returns. You know who isn’t having these sorts of conversations, many of our moron politicians and the fools who vote for them.
LikeLiked by 1 person
The Minnesota monthly average for gas & electric is $198. That’s the figure I cited. Our monthly house average last year was $223 – a little more than the average – but we have 5K heated square feet. That’s 2.6x the average house in our state.
The reason we are so much more efficient is that we have a fantastic HVAC system, in-floor heating in 40% of our space, and really thick spray-in foam insulation. We keep a couple of our upstairs bedrooms (we’re on the main floor) with the vents closed.
I’m not sure how many KwH we consume. Our power company has a terrible app that never opens! 😦
LikeLiked by 1 person
That is really affordable for 5000 square feet. I think I found a website that lists your Electric Rates. https://mn.my.xcelenergy.com/s/billing-payment/residential-rates/residential-plan
Your rate is 13 cents per KWH from June to September and 11 cents per KWH from October to May. Tack on another $6 per month service charge. For ballpark figures, let’s assume that natural gas for cooking, heating and water heating takes up half the cost, so your electric is estimated at $111.50 per month. If Xcel suddenly jacked their rates to match SCE then your bill would raise to $111.50 * 33.3 / 13 = $285. Add the natural gas charge back and you are at $396 per month. Of course, if your company started gouging you for natural gas California style, then your bill would go even higher.
If I had your rates then my electric cost would reduce to $323 * 13 / 33.3 = $126 per month. Maybe I should run a really long extension cord to Minnesota?
Here is trick that may help you get into Xcel’s website. Many websites including the Social Security and Medicare, my tax prep and the price gougers at SCE don’t work on browsers other than Microsoft Edge. Programmers used to check test functionality across all the major browsers including smart phones before releasing new code. I couldn’t get any of the listed sites to work until I tried Microsoft Edge.
LikeLiked by 1 person