I'm a new home owner and was wondering if there is a "right" way to use the double hung windows in the house. Should I open the top or bottom? Is there a seasonality to it? Does it even matter at all?

Double Hung Window

I've looked around and haven't seen this answered well or with most anything other than a "try and see."

Generally, is there anything special I should know to maintain the windows?

Can anyone shed some light?

  • 6
    Vote to reopen as "Best practices for a specific task." is on topic, and window maintenance/repair/operation is definitely DIY related. Aug 27, 2012 at 18:37
  • When I closed it, my thinking was that this is a general homeowner question, and not something that has to do with home improvement. I know there is an "is there something I should know to maintain the windows?" in there; if that were the main part of the question, I think it would be acceptable. Aug 27, 2012 at 18:46
  • I went back in forth in my head with the same question but I ultimately settled on the way The Evil Greebo was thinking. Thanks for eyes on this.
    – Rob
    Aug 28, 2012 at 12:17
  • 1
    I open the top, it helps keep the damn cat off the screens while she looks out the window.
    – Freiheit
    Aug 30, 2012 at 13:22
  • My home is 112 years old. I recently had double-hung replacement storm windows put in. I had the same question about which to open: top, bottom, both?? My downstairs has 9' high ceilings and ceiling fans in dining room and living room. I live in SE Colorado and our prairie summers reach 100 or more degrees in July and August. My upstairs bedrooms have only 7' high ceilings which slant on the sides as this was originally an attic. It can reach 90 degrees up there on 100 plus days. Before we had AC upstairs, I would wake early and open the windows wide, place a box fan on the sills, and try to p
    – user39160
    Jul 6, 2015 at 2:27

8 Answers 8


From treehugger.com

"When air passes over your home, it works the same way as it does over an airplane wing: the Bernoulli effect causes the air on top and on the downwind side of the house to be at a lower pressure than on the upwind side. So if you have double hung windows, you can open the bottom section of the upwind side of the house (usually west) and the upper section of the downwind side (usually east), and the low pressure will suck the air through your house. Make the outlet openings (top section) larger than the inlet opening (bottom section), it increases the draft."

  • well.... treehugger.com in not a science website.
    – IceCold
    Oct 27, 2021 at 15:53

If you open both the top and bottom about 3" the hot air goes out the top and cooler air comes in the bottom.

  • 3
    Tall windows on rooms with 12' ceilings = Antebellum Air-conditioning in the southern US until electricity and modern air-conditioning units became available. The high ceiling kept the heat well above you and the high and low window openings allowed for air flow. Mar 18, 2013 at 22:53

Generally one opens the bottom window, simply because it's easier. The features of the window tend to be designed with that in mind:

  • the screen (if it is original to the window) will usually have a bit of extra fill along the top edge where it meets up with the upper window's bottom edge
  • if there is a partial open lock (that prevents complete opening) it'll be designed to stop the bottom window from opening more than a few inches (though it really works both ways.

It's really up to you, however. There are good reasons to open the top instead - for instance, if you have small children and having them climb around the window is a concern. (No kidding - my friends 5 year old fell out a 3rd story window when the screen popped out)

  • Follow Up: Another consideration to opening the top -my preferred method to keep papers from flying around the room- is that in relation to that gap @The Evil Greebo mentioned above. We had stinkbugs this past summer and I eventually found them getting into the house through that small gap created by the missing edge on the screen. Small but nice to know up front.
    – Rob
    Dec 14, 2012 at 15:30

If you have regular blinds/shades you may find it more useful to open the bottom, since that will allow unrestricted airflow. If you have Top Down/ Bottom Up blinds/shades, you might find it gives you a bit more privacy if you open the top of the windows and blinds.

Some windows will have locking mechanisms that allow you to lock either the top or bottom in place, while the other moves freely. In this case, it can offer better security if you can lock the bottom and open the top. A burglar would have to climb higher to gain access to the open window (though they could always just smash the windows, so it's not a huge security gain).

You may have animals (cats, etc.) that enjoy the open window, in which case they'd probably prefer you open the bottom.


For bedrooms with only a single window, in the summer I like to put a window fan in the bottom (blowing in) and then open the top of the window to vent. Alternately, if there's an AC in the window but you don't want it on, you can open the top of the window to get fresh air without removing the AC unit. (My windows have screens that can slide up to the top of the window which is nice, although not all are like that.)


If you have awnings or eaves that overhang the windows, opening the top may reduce the chance of rain blowing in.


Opening the top sash allows for ventilation while maintaining privacy via top-down-bottom-up blinds, obscuring textured glass, or a similar solution for the still-closed bottom sash.

top down bottom up blind


The top opening of the window was designed to let heat out of the structure it's installed in, while the bottom half was designed to let in cooler air because heat while cooler air tend to stay at the bottom during warmer periods of the year. If you any windows installed the upper portions of a structure, and want to cool it down a bit. Open the upper window while also opening the lower window in the structure to let cool in while hot air is vented out. I hope this answers shed a little light on the subject.

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know the details of contributing here. Jun 22, 2020 at 11:00

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