Caught this article yesterday about how homeowners are using simple math to size overhangs and awnings for their windows, so you get shade in summer but still let in winter sun. The whole thing made me realize I’ve just been guessing all these years… Like, I always figured “wider is better,” but apparently you can actually calculate it based on your latitude and the angle of the sun during different seasons? Some folks use cardboard mockups or even apps.
My neighbor did something similar last year and swears her living room’s way cooler now, but I’m a bit skeptical—does it really make that much difference in energy bills? Also, does anyone else find the math kinda intimidating? I’m tempted to just go full trial-and-error with plywood before committing. Anyone tried this DIY or found a hack that worked (or totally failed)?
I totally get the math intimidation—my brain just sort of glazes over when I see those sun angle charts. Last summer, I tried the cardboard trick for our south-facing windows and honestly, it helped way more than I expected. The living room didn’t turn into a sauna by 4pm, and our AC ran less, so the bill dropped a bit. It wasn’t a huge savings, but enough to notice. Trial-and-error feels less scary than calculating degrees and latitudes, at least for me. If you’ve got scrap wood or cardboard, why not play around before making anything permanent?
I get the appeal of just winging it with some cardboard, but I’ve seen that approach backfire a few times. Last year, a client did the same—tacked up plywood “just to see”—and ended up blocking way more light than they wanted. Come winter, their living room felt like a cave. They called me in to fix it and, honestly, we had to redo the whole thing since the shade was too deep for our latitude.
I’m not saying you need to bust out a protractor or anything, but sometimes a little math up front saves a lot of hassle down the line. There are some simple online calculators that’ll spit out rough numbers if you punch in your zip code—nothing fancy. I’d rather spend ten minutes on that than patch holes or buy new materials twice.
Cardboard mockups are handy for getting a feel for things, but I’d treat them as step one, not the finish line. Sun angles can be sneaky... what works in July might be miserable in December.
I totally get the urge to just eyeball it—I've done the cardboard trick myself a few times. But yeah, I learned the hard way that what looks good in August can make your living room feel like a bunker come December. What worked for me was using one of those sun angle calculators online (just Googled “overhang calculator” and punched in my zip). After that, I cut some strips of cardboard to match the suggested depth and taped them up for a few days, just to see how the light moved at different times. It wasn’t perfect, but it gave me a decent idea before committing to wood. Definitely worth ten minutes of math so you don’t end up regretting it later.
I used the calculator method too—honestly, it’s more reliable than guessing. My overhang is 30" now, and the difference in summer heat was noticeable, but winter sun’s still decent. The math isn’t fun, but it beats redoing lumber every few years.
The math isn’t fun, but it beats redoing lumber every few years.
Yeah, that's pretty much the heart of it. I’ve seen folks just eyeball the overhang and end up with warped boards or sun-faded floors in a couple seasons. Thirty inches is a solid choice—enough to keep the worst of the summer rays off, but not so deep you lose winter warmth. Did you notice any difference in glare inside, or is that about the same? Sometimes even a few inches can change how much light bounces around indoors.
Makes sense—thirty inches seems like a sweet spot. I did a 24-inch overhang a while back and honestly, the glare inside was still noticeable in the afternoons, especially in summer. You probably made the right call going a bit deeper. Did you find it changed the vibe of the porch much? Sometimes it feels cozier with a little extra shade.
Sometimes it feels cozier with a little extra shade.
I get the appeal of a deeper overhang, but sometimes “a little extra shade” just makes things feel boxed in. I went to 32 inches once and suddenly my porch felt more like a cave, especially on cloudy days. Maybe it’s just me, but I’d rather deal with a bit of glare than lose that open-air vibe. It’s a trade-off for sure.
I went to 32 inches once and suddenly my porch felt more like a cave, especially on cloudy days.
That’s been my experience too. Years ago, I thought a bigger overhang would be the answer to all the summer heat, but after I extended mine out past 30”, it started feeling more closed off than cozy. There’s definitely such a thing as too much shade—especially if you’re somewhere that gets a lot of overcast days.
If I could do it again, I’d probably go step-by-step: start with something modest, maybe 18–24”, and see how the light shifts throughout the year before committing to anything deeper. Maybe even use something temporary for a season—an awning or sail—before spending on a permanent structure.
One thing folks forget is how much the angle of the sun changes from summer to winter. What blocks harsh sun in July might just make things gloomy in December. It’s all give and take. For me, I’ll take a little sun if it means I can still see the yard and not feel like I’m sitting in a tunnel.