Heat Reflecting Window Film

[jyl]

I have a former “sleeping porch” that was glassed in. It gets very hot in summer, and it’s not practical to AC.

I was thinking about using some window film to reduce the heat entering the room. Ideally without turning the room into a dark place, or making the house look like it has mirrors for windows.

Have you used the stuff? How effective is it? Any tips for selecting the best stuff?

[Steve Carlton]

I would talk to a local car window tinting place. You block heat by blocking infared, but you probably should block UV as well if you're going to be in there when the sun shines. I'm sure there's film for both, and (at least with IR), it can even be clear, although you'd probably want some tint to it.

[cabmandone]

3M makes several products just for this purpose. I haven't installed yet since the place where my son works hasn't gotten set up as a dealer yet. There are some kits you can buy on Amazon but I don't know how they stack up against 3M's product.

https://www.3m.com/3M/en_US/home-window-solutions-us/solutions/temperature-control/

There must not be much demand for it, but I've thought that having windows that work like Transitions lenses would be nice.

[berettafan]

Can I add a question on this?

Does this sort of reflective film cause issues with double (or triple) pane windows?

[cabmandone]

Originally Posted by berettafan

Can I add a question on this?

Does this sort of reflective film cause issues with double (or triple) pane windows?

From my understanding, no it does not. It is supposed to improve their efficiency. Some double and triple pane windows come with a low e film installed. There are films that can be applied inside or outside depending on your preference. All the film is doing is reflecting IR and UV rays to reduce radiant heat gain in the home.

[berettafan]

ok that's good to know. I guess I was wondering if that reflected heat wasn't overheating the sealed area between panes.

[onewhippedpuppy]

I think Steve nailed it. I would look at a high quality ceramic tint that’s clear or very lightly tinted, they offer it typically for tinting windshields. I’ve tried it on a past vehicle and it was very effective at reducing the heat on sunny days.

[cabmandone]

Originally Posted by berettafan

ok that's good to know. I guess I was wondering if that reflected heat wasn't overheating the sealed area between panes.

Unless that heat is being retained, it shouldn't do any harm. And since that heat is passing through, it doesn't seem like it can be retained if it's diverted back out. And if concerned, use the exterior type of film so the reflection happens on the outside rather than allowing it to pass to the inner pane and then reflect out.

[masraum]

Originally Posted by onewhippedpuppy

I think Steve nailed it. I would look at a high quality ceramic tint that’s clear or very lightly tinted, they offer it typically for tinting windshields. I’ve tried it on a past vehicle and it was very effective at reducing the heat on sunny days.

I've wondered about something like this myself. I've installed tint before, it's easy. The hardest part is precision cutting it so it looks good and isn't obvious. THere are places where this sort of thing seems like it would be a huge improvement. It seems like from FL straight across to AZ at least, possibly SoCal. For stuff that's not in the deep south you may actually not mind some heat in the winter, so that would be a consideration for me.

[jhynesrockmtn]

I have been following a thread in the tech section on electric AC. There is a lot of discussion there about various window film products to reduce cabin heat.

https://forums.pelicanparts.com/porsche-911-technical-forum/921754-classic-retrofit-lightweight-electric-air-conditioning-95.html

[Cajundaddy]

"Low E" window tint or film offers a lot of reduction to heat in sunrooms. The higher the reflectivity, the better the heat reduction.

We had a kitchen on the south side of the house with a lot of windows and no room for a practical awning for shade. It was so bright in that kitchen it looked like a Spielburg movie and it got hot in there every summer day. No amount of redirecting A/C airflow would solve it. Rather than reflective tint I added exterior screens that blocked 80% of the light and heat. I put them up in June and it greatly reduced summer heat and the overabundance of light in that room. You could still see fine through it as we did have a nice view of the city, but it reduced heat in the kitchen by 10*F. In October I would take down the screens, wash the windows and we benefitted by the light and heat gain during winter months.

Just another option.

[Tobra]

Put film from Home Depot on a bedroom window in my house. Room was definitely cooler.

How about a swamp cooler, or a redneck ice chest/box fam air conditioner?

[jyl]

Originally Posted by Tobra

Put film from Home Depot on a bedroom window in my house. Room was definitely cooler.

How about a swamp cooler, or a redneck ice chest/box fam air conditioner?

The former sleeping porch has weird windows - up high. top-hinged, swing out. I have a couple of portable AC units and will McGyver up some way to get the AC hoses mounted in the window. But those things are power hogs so good to reduce the AC load.

I'm putting minisplits in the bedrooms this month - including in the bedroom that the former sleeping porch is connected to. However, we need to keep the door from porch to bedroom closed most of the time for pet reasons.

[Tobra]

Those windows are designed for places without AC, let the heat out

Maybe sunshades outside the window, or trees to shade the area

[jyl]

Take longer than I’ll live to grow a tree that tall . . . and I don’t want to be installing and maintaining sunshades 30 feet above grade.

It’s going to be whatever windows film does - then blinds and/or AC for the hotter periods, which are thankfully still only a few months a year.

[cabmandone]

Originally Posted by Zeke

Tinted films do nothing, just dark glasses on your openings.

That's not exactly true. To the degree that a standard tinted film does nothing, yes that's true. But the films designed for residential and commercial windows have a stated U value and heat gain coefficient. The 3M P70X allows 70% of light to pass through, has a U value of 1.02, a heat gain coefficient of .48 and claims to reject 52% of total solar energy. I've really got to get this stuff bought and installed. It'll be fun checking floor and furniture temps (I have a sickness) to see what good it did.

Oh... and yeah a home energy audit is a wonderful thing. It helped me find where my worst air leaks were coming from and address them. I now have a home that is over 100 years old sealed to the minimum building standards of today which seems pretty good for an old home.

[Steve Carlton]

AI Overview
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Window tinting can absorb a significant amount of infrared (IR) radiation, with many films boasting infrared rejection rates of over 90%. However, it's important to note that IR radiation only makes up about 53% of the total solar heat. Some films, like XPEL PRIME XR Ceramic, offer up to 85% infrared rejection. Other films, like the 3M Ceramic IR Series, can achieve up to 95% infrared rejection. According to a reddit user, 70-90% is a normal percentage for infrared rejection, and some products can reject up to 99% of infrared radiation.

I googled "what percentage of IR is absorbed by window tinting"

[Steve Carlton]

Sorry to be an armchair googler, but in my automotive glass experience, tint that is designed for reducing IR radiation (the kind that generates heat) is incredibly helpful. And it can be clear- tinting isn't a factor.

[jyl]

Well, I have some film coming and maybe it’ll do a little bit. I’m also going to figure out how to run AC hoses through that tilting window.

[Steve Carlton]

Originally Posted by Zeke

So WTF did I say? Tinting isn't a factor, to use your words.

Pelican IQ. Leave me alone. Pick on your friends here.

You seem to have deleted your earlier post(s), so I don't exactly remember "WTF did I say?" I said in post #2, before you lectured us in your 'expert post that we don't deserve.' You're an angry piece of work, dude. You're the one implying we think tinting to make glass darker is what reduces heat. I'm just clarifying that's not the functional element of it.

I'm happy to 'leave you alone.' Don't expect that to happen when you accuse me or others of ignorance or armchair googling.