Normalizing temperature between floors
We have a two story house with central air that shares an open stairway between floors. Master suite is located upstairs, and when the air is on, downstairs will be comfortable (75) and upstairs will be about 85 or higher. I’ve shut down all the vents downstairs to force all cool air upstairs, but that doesn’t make any difference. The only way I’ve gotten this to work is to open a window upstairs and put a fan blowing outwards to expel the hot air. I hate having to have a fan running in addition to the AC, and am looking for solutions. There is only one air return vent upstairs, located just at floor level at the top of the stairs.
Do I need to try to move it up to the ceiling for summer? Located in the upper midwest if that makes any difference.
Replies
Cold air is harder to move than warm air. Can you speed up your fan, many blower motors have a multi speed winding that runs the motor faster when cooling is called for. Hot air rises cold air sinks. Roger
Not sure about whether that is possible or not. The system in question is a Carrier Weathermaker 9200. I'm not afraid to mess with it, but I don't know what I'd be looking for.
"There is only one air return vent upstairs, located just at floor level at the top of the stairs."
could the return vent be sucking most of the cool air before it hits the rooms upstairs?
bobl Volo, non valeo
Baloney detecter
You are getting a bunch of stale air that is not circulating upstairs. That return register needs to be moved to a spot much farther away, or better it should be split so it pulls out the hot air from all the upstairs bedrooms.
Another thing you can do (I had pretty much the same problem) is get the magnetic pads you can cut to size to place over your registers downstairs - this made a big difference for us. Turned out that the closest register was nearly impossible to cap off - most of our airflow was going to a 4'x3' bathroom downstairs! Capping it just blew the register off. I finally blocked it off with a piece of foam insulation - the duct was in the slab itself. Also, you might want to set a 20' floor fan at the bottom of your stairs blowing up the steps - it will help with the exchange of air too. Also, turn the switch on your thermostat to "Fan ON", this will keep the system running even if it isn't actively cooling - again circulating the air more.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
How is your attic insulation? If you are not close to R-38 then adding insulation will help, and save money too.
"There is only one air return vent upstairs, located just at floor level at the top of the stairs."
Dat's the problem.
I havbe two separate furnace, but only ONE AC and that is on the 2nd floor.
Returns in each bedroom up high.
The 2nd floor is always comfortable and the bottom is except in the hotest weather.
But I have an entrace at the 2.5 floor level without and supply or return registeres and it gets hot.
Bill makes the right point, as well as osme others.
I might take some extensive and envasive work, but you need to get return air vents in each room, and balance them to the amount of supply air. Depending on your floor plan, the now single return at the top of the stairs, might be the proper size for the total area or not. If it is you can plit it into the correct sizes for each room and blank off where it currently is located.
A central return near the staiway only serves to draw the cool supply air toward the open stairs. Most of it will then just cascade down the steps to the first floor. Placing return airs in each room, high on interior walls will keep the cool air where it need to be, in each room.
Dave
There is only one air return vent upstairs, located just at floor level at the top of the stairs.
I bet when you are upstairs in bare feet, your toes are cold, too! They are in my house. To confirm what others have said, I have the same problem at my house. I had an HVAC contractor in last week, and he commented the only way to fix it is to re-do the ducting. The ducting was originally laid out for heating only, and the central AC was a retrofit. 'kinda ticked me off; I had a remodel done a couple of years ago and asked the GC a couple of times, when the drywall was all ripped up, whether the returns should be moved, but he blew me off. Even now, I could steal some closest space and get to the attic that way, though.
I was thinking of doing an "experiment"; i.e., building some rectangular tubes out of hardboard or something, and using them to extend the openings of the two returns up 5 feet or so, and seeing if that makes a difference.
Just typed a long message, and hit post, and it went poof!I extended my return up to about 6 feet using a cardboard box from a set of closet doors. I have it leaning in place, and its not a tight fit, but the temperature dropped upstairs about 7 or 8 degrees. I figure I can get a little more cooling if I run it up to within 6" of the ceiling.Aside from the looks (DW wants something better) it does work. I have to get a better seal around the existing vent (located in the wall) and make it somewhat removeable for heating season. Fortunately I have paint left over that will make it easy to match to the wall.Definately an improvement.
Fascinating. 'makes sense. Here in Western Oregon it doesn't get super-hot (>95) all that often; I could even live with only doing this on those days.