What's new

AC question

I live in a 2 story home that has high ceilings. I only have 1 AC unit. The upstairs is always hotter than the downstairs (logically). I have the thermostat set at 75 during the day and 74 at night. I can't sleep when it is hot. I also believe that since temp drops in the evening that the AC unit will not have to run as hard this way vs if I had the temp 74 during the day and 75 at night.

My question is would it help even the temp if I left the fan on versus on auto?

Will my energy bill be much higher if the fan is always running?

Would it be better to just turn temp down 1-2 degrees across the board?

I am afraid to try to adjust to temp down to say 73 during day and 72 at night. I have had energy bills in the past when I would always adjust the temp if I was hot and my bill seemed to increase by $150 and I never even adjusted it below 70.
I saw a thing on Ask This Old House on this. Their solution was to put an airbag system into the vents. You have temperature sensors in each area in the house, they run air line through your existing ducts and attach an air bladder on the end of the line (in all your ducts). The sensors are linked to an air pump/vacuum and it inflates and deflates the bags to control how much air is going through the vents. I will see if I can track it down on the site. Fairly inexpensive compared to most options it looked like.

Found it - http://www.homecomfortzones.com/

And realizing that does not answer your question, but there ya go. :)
Last edited:
I used to have a multi-level house and the lower level kept very cool, while as you are experiencing, very warm on the upper level. I closed the lower level vents completely and kept the upstairs fully opened. Just doing that helped immensely.
What Sue said. Remember that cool air sinks and hot air rises. Perhaps a fan in the stairwell would help circulate the air better.
Unless you are willing to invest some significant money in improvements, Sue's suggestion is a good one. :thumbup1:

Just be careful and do not reduce the total airflow too much. You could actually freeze the cooling coil.

You will most likely find that balancing the system twice per year (once at the beginning of cooling season, and then again at the beginning of heating season) really does help significantly. You may find that reducing the airflow downstairs (particularly near the thermostat) helps by forcing more air upstairs. And also by keeping the system cooling a bit longer before the thermostat is satisfied. You will most likely also find that you need to reverse this balance process for the heating season.
Last edited:
I used to live in a split level and had the same problem. There should be an adjustment on the ductwork that you can use to control the airflow. If you try to adjust using the floor vents, they can get noisy unless they are opened a little. Easy to do and worked well. Changed the flow every spring and fall. I also tried using a booster fan on individual air vents but that really didn't work well.

Commander Quan

Commander Yellow Pantyhose
You could purchase a small window air conditioner to cool just your bedroom. If you only turn it on to cool the room in the evening it shouldn't have any problem cooling it down in 30 minutes, and then it will run when it needs to overnight. I don't believe these are as efficient as a Central Air unit, but it has to be more efficient than dropping the temp in the while house. I have a old 2 story house with a finished attic and I just bought a window unit to cool it. There was only one vent up there and the air conditioner didn't help at all.
I thought about closing some vents and tried it in the past without a whole lot of success.

Maybe I will try again.

Also I have a "flute" I think is the term in my attic to direct the flow. I always have it marked summer which I think is open.
Top Bottom