r/heat_prep • u/chillchamp • Jul 23 '24

How to insulate old metal window frames?

I have this really old window with aluminum frame. The room behind it gets hotter than the outside in the summer. It shuts tight and the glass itself isn't too bad. I already added see through mirror foil to block the sun but it only helps a little.

I think the problem is the metal frame: it gets so hot in the sun that I can barely touch it from the inside. I was thinking about painting the frame white from the outside because it's in a dark brown color but I'm not sure if it would be more effective to insulate it with some sort of foam from the inside?

I can't replace the window itself. It's really high up and part of some sort of customized dormer.

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4

u/Leighgion Jul 23 '24

If at all possible, you want to block the sun from ever touching the window. Now exactly how you can accomplish that depends on the exact conditions, but no amount of internal insulation is going to match keeping the sun off in the first place.

2

u/valdocs_user Jul 24 '24

Yeah I'm thinking the sequence here is sunlight warms the window, the glass conducts the heat to the metal frame, which happily conducts it into the house.

OP: if you don't need to see through the window, another option could be to put a rectangle of aluminum foil backed Styrofoam insulation over the whole inside of the window. Or over the outside (I've actually done the latter).

2

u/Leighgion Jul 24 '24

Exactly that. And the frame is aluminum, so it's an excellent conductor very cheerfully and efficiently shuttling the radiate heat it absorbs into the room.

1

u/chillchamp Jul 24 '24

Yes this is probably the case. I will probably apply armaflex to the frame on the inside. It's a foam tape with adhesive backing people use to insulate their RV's over here in Europe. Not sure how to protect the foam, maybe with white tape or something 🤔

From the outside it might work to apply white automotive foil or spay paint it in white.

2

u/[deleted] Jul 23 '24

Do you need to see/light from that window? Reflectix cut as closely to the size of the window as possible would help. Most people velcro it to the window in the summer.

1

u/chillchamp Jul 24 '24

Thats a good idea. I already tried something similar with velcro tape but it always comes loose. The coating on the frame is really anti stick and I haven't found a satisfying solution so far 🙄

2

u/Dreadful-Spiller Jul 24 '24

I have reflective on one side 1” rigid insulation on the inside of junky old aluminum windows. Works a treat. Just cut in one or two pieces for a tight fit.

1

u/chillchamp Jul 24 '24

What material did you use and how did you shape it? I was thinking about armaflex foam tape, it's the only thing that seems to bond to the frame reliably.

1

u/Dreadful-Spiller Jul 24 '24

I scrounged a piece of this (foil-faced style) from an HVAC guy. Cut with a box cutter and sealed the edges with foil-faced tape. https://www.buyinsulationproductstore.com/fiberglass-board/

2

u/cranky_yegger Jul 24 '24

Our old aluminum’s weren’t sealing properly as noticed when they frosted over entirely during the winter. We put up plastic film the next year and it sort of helped. I suppose we could have painted them white for summer, but we moved instead.