All the cold air from my AC flows through a stairwell and into the basement. The entrance to the basement is the through a doorless opening on the 1st floor.

I am planning to put up a curtain in that entryway to block the precious cold air from flowing down to the basement. I’m thinking of using a tension rod since I don’t care if there is an opening at the top of the curtain. only the hot air would flow through. However the bottom must be touching the floor and should seal off any cold airflow.

Would this method work? If so, is there a particular kind of curtain available with weighted bottoms or rubber bottom that can stop airflow?

Any insight would help! Thank you

  • Perhaps you also benefit from the air changes this causes? Have you considered that?
    – Solar Mike
    Commented Jul 9, 2020 at 7:10
  • Is your return air to your unit in the basement? Commented Jul 9, 2020 at 12:16
  • @SolarMike you're talking about "air changes" of moving cold air from upstairs and allowing it to push the (potentially) stale air from the basement up to be freshened/moved out of the house? It took reading your comment several times to pick out that meaning. Maybe I'm just slow this morning...
    – FreeMan
    Commented Jul 9, 2020 at 12:17
  • There is no return in the basement. The HVAC unit is on the second floor as well as the returns. The basement leads to the garage where I don’t think there is any return there either. Commented Jul 9, 2020 at 22:00

1 Answer 1


A curtain will work nearly as well as a door to block air flow. It will not seal (nor will an interior door unless you weather strip it), but it will significantly reduce the flow going downstairs.

A heavy curtain material will do more to resist the flow of air than a light material will. A light curtain will have a higher tendency to just blow, based on how strong the airflow is.

Simply look for a curtain that is made from a heavy material then hang it low enough that the hem lies on the floor. Alternatively, you can buy a curtain designed for a window that's taller than your door and hang it at the top of the door opening while still having the hem sweep the floor.

You'll probably have to be diligent to ensure that the curtain closes neatly behind you each time you go through the opening because the drag on the floor will probably prevent it from just swinging back to a fully closed position.

If you find that even the heavy curtain you purchased is blowing and not sealing well, use a seam ripper (or small, sharp, pointed pair of scissors) to open up the bottom hem (at one vertical end of the curtain, not the entire horizontal seam) and slide a metal or wooden dowel into the bottom hem to weigh it down.

  • That is excellent advice. I was thinking along the lines of lining the bottom hemline with rubber strips to give it weight. But I guess a wooden dowel will work just as well and is easier. Commented Jul 9, 2020 at 22:02

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