We moved here in 2016 and have used this method to great success. In the Summer each morning after cooling the house down using the free open window method if the humidity is comfortable. On the lower-level thermostat, you set the heat cool to the off position and turn the fan to the on position and leave it for the day. I always do this first to insure the blower motor is on. Of course the windows are shut.

We have a Nest thermostat and we set the air conditioner to at least three or four degrees above the actual main floor temperature. That will insure the air conditioner will not run until it reacher your tempature setting. We usually run the fan for an 8 hour setting. We have determined over the past six years, that our lower level where Since we use our lower level alot as I have a painting studio and Linda a sewing room,  we enjoy the lower level tempature rising  from 69/70 to 74 or 75 degrees.

A great place to check this is to check the main bathroom vent from the lower level and feel the cool air.

During the winter, we follow the same method and use the warm upstairs air to warm our entire home. Since we live on Flowerfield Road, our porch can reach 80 to 85 degrees in the sunny winter days

Dan Wagner

This morning after having the windows open we lowered the house tempature to 73 degrees. We at 8:30 am will close the windows and turn on the lower level thermostat to run only the fan. The tempature in the lower level is now 70 degrees. At the same time I will turn the upper level Nest thermostat to have the air come on at 79 degrees and I also set the upper level thermostat to also run the fan only.

This will result in the lower level cooler air to come out of the upper level heat run vents and of course the upper level warmer  air will come out the lower level vents.

Since this is going to be a 90  plus degree day I will report to you the upper level and lower level tempature at noon and also at 5pm.

Dan Wagner

At noon, our air conditioning has not turned on and we have it set at 79 degrees. Outside it is 90 degrees and the lower level is now at 73 degrees and the upper level home tempature is 78 degrees. No doubt the air conditioner will run some this afternoon but it will cycle with the whole house fans continuing to do their job until this evening.  Our lower level should continue to warm to perhaps 75 degrees.

This is documented proof that this system works!!

Dan Wagner

Hi,

Hopefully this is my last note on this subject.

My dad owned a very successful furnace business in Duluth, International Falls and Hibbing. He taught me to be certain the house have adequate or more heat and cool air vents. So when the our home was being built, I added nine heat runs to the lower level instead of the planned 6. My neighbor with the same home indicated he had  5 or 6 heat runs in the lower level. Nine might sound like alot but I like my office warm in the winter and Linda likes her sewing room warm in the winter and cool in the summer.

So the answer is most likely not the thermostat but the difference in heat runs and thus air flow. My neighbor used my method yesterday and it worked but the main floor was getting less cool air and the lower level did not warm up like our home does. Our lower level gets up to 74 and his was like 72. (although 72 is still 2 or 3 degrees warmer than 69 and it is free heat!

So there you have it. If you have any questions, you can call me at 651 653 5890.

Dan Wagner