Vinyl Windows Equals Less Light

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Picture of beautiful sun halo

The winters in Northern New England are long and dark. Sometimes you can go weeks without really seeing the sun. So capturing as much of the winter sun as you can get is vital to fighting the winter time blues.

Recently we decided to test a hypothesis that we had noticed–the upstairs vinyl windows seemed to let in less light than the downstairs original wood windows. So we broke out the rulers.

First, take a look at the windows below and you can instantly see the difference in window size. The pictures were taken at the same time facing the same direction (vinyl upstairs and wood downstairs) so that any differences in lighting is due to window size.

Picture of Original Wood Window

Original Wood Window

Picture of Replacement Vinyl Window

Replacement Vinyl Window

So now it is time to break-out the ruler to see just how much less sunlight the smaller vinyl windows are not letting in. The first picture shows that the frame of the wooden window is 1.5 inches. The second picture shows that the frame of the vinyl window is 3 inches. As such, we are losing 1.5 inches of window on each side.

Picture of Wood Window Frame at 1.5 inches

Wood Window Frame at 1.5 inches

Picture of Vinyl Window Frame at 3 inches

Vinyl Window Frame at 3 inches

The length of the windows are both 60 inches. So multiply 60 inches by 1.5 inches by 2 sides equals 180 square inches of lost window space. But, how much is 180 square inches?

To answer that question we took some black construction paper and cut it into a square that contained an area of 180 square inches. Now it was time to do some math we haven’t done since high school which was way back . . . oh, never mind 🙂 We took the square root of 180 and got 13.4 inches.

The picture below visually shows the results our calculations. As you can see, the 13.4 inch X 13.4 inch square is actually a lot of lost window space. The previous owner replaced all 5 upstairs windows, so that amounts to 900 square inches of lost winter sun–the equivalent of boarding up more than half of one of the wooden windows!

Picture of Original Wood Window Blocked Out

Original Wood Window Blocked Out

It’s not hard to understand why this is. The wooden windows are very strong and are built right into the house. The vinyl windows are not as strong and come within their own frame for support and installation. It is the frame that is crowding-out the window space.

Of course, in fairness, our wooden windows has a vertical center muntin that blocks sunlight, but we also didn’t figure in the the differences in the upper and lower rails. We just assumed that they pretty much offset one another. Overall, we feel these estimates are pretty conservative and that more light is being lost than what we have calculated.

We all know the aesthetic reasons to stay away from vinyl windows–they are ugly! Now we have a pragmatic reason to stay away from vinyl windows–they can increase seasonal depression by blocking the precious winter rays from the sun.

Please share this post with all of your friends, especially the ones that still have wooden windows. If this post stops just one person from installing vinyl windows we will be ecstatic.

Of course, vinyl siding is just as bad and if you missed our recent post, “Undoing the Damage from Vinyl-Siding,” please check it out along with all of our Vinyl-Vandalism posts.

And please go ahead and vent about vinyl, in all of its ugly forms, in the comment section below 🙂

Update: Check out the window restoration resources from John Leeke (see comment below). He has two websites full of how-to advice:

You can buy his book here:

Please add your thoughtful comment . . .