Insulate Hollow Garage Man Door

[AndrewDouglasBird]

A little background first. I'm renting an apartment with an attached garage. The downstairs is always super cold while the upstairs stays warm due to the thermostat being upstairs (forced air heater). If I heat the garage with a small electric heater, the entire downstairs is significantly warmer, but this kills my electric bill. I'm thinking the door from the house to the garage might be losing a lot of heat through it. It's a steel door and seems to be hollow, though I haven't verified yet.

The seal around the door is great, no visible light showing through with it closed. This is why I was thinking it might be the door itself.

I've read where people drill a hole in the top of the door and fill it with spray foam. The only concern is a lot of doors have a honeycomb of cardboard on the inside, making it so you can't fill the door completely. Anyone have experience with steel doors and this?

Another idea is to attach a piece of rigid foam insulation on the garage side of the door, but I read this violates code due to the fire hazard of the foam.

I obviously can't replace the door as it is a rental and the landlord won't replace it (judging from experience with him).

Any ideas on what I might be able to do to help keep the cold out?

 

[The Cobbler]

Hollow metal door will have a honeycomb of cardboard .

 

[NUTTSGT]

Does the garage have an open ceiling or a closed off attic space, just curious.

I know what I would do but you're worried about violating codes.

 

[rslaback]

Personally I don't know that I've ever seen a hollow steel door outside of an inside commercial application.

 

[Erampu]

I wonder if a cheap storm door on the garage side would make a significant difference. You could put some rigid fiberglass on it and take the whole thing down when you move.

 

[Nowater]

Cover the garage side with layers of corrugated cardboard. It has an estimated R value of about 2 per inch which is about half that of fiberglass. You should be able to recycle some boxes, and it is no more flammable that the same boxes sitting in your garage and it is a cheap way to test your theory about the door's heat loss.

Make sure the material is not pressboard like a cereal box, but that it has corrugations. The trapped air is where the insulating value comes from.

 

[Lippyp]

I insulated the inside of a particularly cold external door with a couple of layers of that doble foil faced bubble wrap insulation, just stapled it on. Personally I'd try that as a start.

 

[bazzateer]

Nice heavy curtain on the garage side?