My husband's life's work has been HVAC. He spends his free time running all sorts of calculations on our home energy usage in excel and spent his first Father's Day installing his "new toy" which was a new Mitsubishi ducted heating and AC unit for our upstairs. We live in the Northeast in a 100 year old home with insulation that is less than optimal (we're working on it). It's not terribly hot here but most summers we'll get at least a few instances of 3-5 days in the 90s with warm humid nights and many days over 80 degrees with high humidity. This is our third summer in this home and the first time having AC for the whole house.
The nights before hotter days we've started supercooling our home, rather than trying to cool constantly through the day. Basically you run the AC hard through the night to cool your home down to a lower temperature than you usually would during the day. This means that you're doing the bulk of your cooling work when it's at least slightly cooler at night, without actively fighting the heat of the sun. You also save money because you're using that electricity outside of peak hours. Then during the day, you turn the AC up to a higher set point and make sure as many windows are covered with curtains, shades, films etc. At night we set the AC to 67 and during the day we set it all the way up to 76 or 78 depending on the outside temperature.
It's too early to know what the exact financial savings will be for us, but we do notice that the AC runs for less time in a 24 hour period and significantly less during the daylight hours. There are days when the downstairs unit does not kick on at all. Typically we would turn off the AC and open the windows at night to cool the house, but that's not helpful when it's over 70 degrees overnight and/or very humid.
It is important to note that you should not set your AC lower than 65 for extended periods, you will risk freezing the unit.
Edit: actually just checked the programming for the upstairs unit, it's on 70F from 7:30pm -12am and 67F from 12am-7:30am.
Here is an article with more information - this is not my husband's company by the way, I am not promoting him here.
June 26, 2022 at 10:44PM
