I have a pretty standard steel double garage door. My garage gets up
to about 145 degrees during the summer mostly because my house faces
the sun pretty much all day. Is there any value to me adding
insulation to the garage door panels? It seems to me that some kind
of styrofoam insulation would fit perfectly in the panels. I've seen
the kind with the metallic coating on it before. Would this help or
am I wasting my time?
depending on your climate: the insulating r-value will determine if it
is helpful. if undesirable heat is entering the home from an attached
garage, increase the insulation in the connecting wall. the material
you are looking for should be a fire-retardant material. a temperature-
operated exhaust fan like an attic fan might be more effective.
structure and existing insulation and the garage's use are items to
You're dealing with radiant heating, so a radiant barrier insulation
will work the best for you. That 1/4 inch foil insulation worked for
us with a metal door that faced directly east. By noon, we couldn't
stand near the door. After installing the radiant barrier foil
insulation, we could stand right next to the door. The outside was a
We did it, it worked for us and made the garage a lot nicer place to
work. It also helped in the winter time.
I had a similar problem mhere in Canada - very hot in the summer and
very cold in the winter. Compoundng the fact, my family room directly
adjoins the garage so it was influenced as well.
I insulated and it made a huge difference. FWIW, I also addressed the
air infiltration problem around the doors which made a larger impact
in the winter.
Also, I originally used a mastic type of tube compound to tag the
insultaion on, but eventually it popped off because of the temperature
shifts. I ended using straps and also the aluminum heating duct tape
which worked well. I simply used the syrofoam sheets cut and notched
on my tablesaw to fit in the door panels.
Presumably you would open the garage door or otherwise ventilate the
garage once it gets hotter inside than out. Otherwise you would be
holding heat in more efficiently in the evening.
My guess is that you would do better to rig an attic exhaust fan with
inside and outside temperature sensors.
What's happening is that the sun is hitting the sheet metal door and turning
the door into a radiant heater. If you place your hand on the interior of
the door, it gets more than hot enough to burn your hand. The door is
heating up the interior space.
That would not solve this specific problem. For a similar situation, I used
a low-expanding spray foam to fill each area. I then attached 1/4" plywood
to the interior frame. It cut the interior heat gain by a good 50F. Instead
of 130F+, the garage now doesn't go above 85F.
Call the manufacturer of your doors. They may have retro fit
insulation. My 10 x10 shop doors were less than $100 each. Vinyl
backed insulation that fit perfectly and came with trim pieces to hold
it in place.
Look in the yellow pages and call some real Insulation places (Not Lowes or
Thats what I did and got some panels that are made specifically for that
purpose and are designed to slide right in..
Inside face of the Foam is covered with some type of tuff vinyl to protect
it from "dings" in the garage
They tell me it helps a lot keeping the temps down in there.
Wasting your time & money. If it really gets 145 degrees in there, then you
have bigger issues than the garage doors.
You need to insulate the whole thing along with the doors. Some attic
ventelation would help too. My garage has R-19 in the walls and R-38 in the
celing. The doors are insulated too. So long as the hot cars are kept out,
it won't get hotter than 85 degrees in there.
Not hardly. Have you ever touched the inside of a sheet metal garage door
exposed to full sun? They become a big radiant heater. And if the rest of
the garage is well insulated, the heat is trapped and very efficiently
I had the same situation as the OP, and once the doors were insulated the
interior temp dropped from an average 135F to 85F.
Commented on above. Big radiant heaters + well insulated garage = massive
heat build up.
I have no attic. There are bedrooms directly above the garage and a
garage door entrance straight into the living room basically. It's
not hard to get that hot in my garage when the ambiant temp outside is
110 and my house faces the sun all day pretty much. I notice that it
is helping already.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.