Adding a hallway door to increase air conditioning efficiency
 

My senior citizen parents have a backsplit bungalow and mostly live on the upper (street) level. They also have very different "personal thermostats" which can make for some amusing heating/cooling conflicts -- eg. my dad wearing long pants and an outside jacket inside the house in the summer while my mom wilts in the same temperatures. They set the summer temp to 74F and in the winter it's 70.

Another small conflict is the main topic of this thread: in the summer, the lower level gets quite cool when the central A/C is running... even though the vents are all switched over to blow only upstairs.

After a few days long "heat wave" with the A/C going non-stop, my dad said it's too cool for him to sit downstairs for any length of time (eg. their computer is down there).

I suggested they put a door on the stairwell between the upper & lower floors to keep the cool air from flowing down the stairs.

Think it's worth doing?

Additional info: the custom ordered door + professional installation would be around $500. One heating/cooling guy I talked to said it'll probably never pay for itself in any reasonable amount of time, but it'll help solve the comfort problem.

The one big downside: due to the design of the stairwell, the only possible place for a door is at the bottom of the stairs. So they would still be filling up the stairwell with cool air before it started to have an impact on the difference between floors.

Filling up the stairway is still much better than filling the whole basement.

When I replaced our basement door with something that actually held back the cold air, there was a large difference during the colder months.

I say go for it!

True.

OK, they're going for it. :)

I took my mom to the store yesterday and she picked out a door. It's NOT the most efficient choice: she decided (smartly) on a mostly glass (think French-style) door because the stairwell is lit by natural light from the lower level during the day. A conventional door with better insulating properties would have been more ideal from an efficiency standpoint, but it would have made for a dark stairwell when closed. (Which will be much of the time during the peak of summer.)

So it seems what we have here is a project that isn't the *best* solution, but it will be an improvement.

I'll update when the door arrives. It'll be here in 2-3 weeks.

Adding a door sweep might help too if there ends up being a sizable gap under the door.

Overall it sounds like a great idea though. Will you be hanging the door?

Sweep is a good idea.

I'm not hanging it... they're getting it installed.

As long there is little-to-no moving air from drafts, then the amount of heat transfered through the door itself will be small, so it's still a win.

I've seen balcony doors, with low-e double pane windows, installed indoors before, for example between a living room and unheated sunroom. Doesn't block light, but is almost air-tight and insulates like an outdoor window.

There shouldn't be drafts where this door is going.

There's also a good chance that the truly hot weather of the summer will be past in 3 weeks! We'll see.

Is it possible to add a return air duct to the downstairs? Or if there are 2 seperate supply ducts make one a return? The idea being to help remove the extra air which is too cold and allow it back into the system.

I'll have to look at where the return is.