# garage door insulation

## garage door insulation (post #206714)

I am looking at insulating my garage door (in LA so I am worried about heat and less about cold).  Looking at an R5 and an R8 solution.  R8 would run about \$140.  R5 about \$85.  I am thinking it would take a LOT of heat savings to pay back that\$60 or am I way off base?

### Do you actively heat or (post #206714, reply #1 of 6)

Do you actively heat or air-condition your garage?

If it's a metal door you can do some rough heat loss calculations based on the inside (the garage) vs outside temp, and then (very roughly) calculate what that amounts to in \$\$, if you're actively heating/cooling the garage.

If you're not actively heating/cooling the garage then any "savings" would be more in terms of comfort in the garage than actual cost savings.

In any event, I'd have trouble believing that the R8 would make much difference over R5 -- diminishing return and all that.

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

### Another factor is the heat (post #206714, reply #2 of 6)

Another factor is the heat that must be removed from parked vehicles. It can be substantial.

Take a fully warmed vehicle running in 90 degree heat and trap it in a garage, and you've got a major thermodyamic issue. Somehow, all that heat will find it's way to equilibrium, either by convection, conduction, radiation, or your A/C system (which has to deal with all three of the others).

### I'm just north of you in the (post #206714, reply #3 of 6)

I'm just north of you in the desert. I insulated my unconditioned garage ... because it greatly extends my hours I'm able to use the garage comfortably. If you aren't heating/cooling it ... there is no savings in energy ... just improved comfort. The metal door has VERY little R-value, so insulating can be good.

Personally, I'd simply fill the thickness of the door with insulation. That's what I did. Most metal doors are like 1 1/2" thick on the inside. I bought 1.5" of polyiso (aprox. R-10) and cut it on my table saw to friction fit to fill the cavity. DON'T use polystyrene (extruded or expanded) unless you plan to cover it w/ a fire barrier ... it's against code to have it exposed ... if a fire started you might not be covered by insurance.

Personally, I'd ignore the 'economics of energy savings' and simply fill the cavity.

There ain't NO free lunch. Not no how, not no where!

### So Brandi (post #206714, reply #5 of 6)

Reflective barrier maybe.............

But why is it you mention R-value?

Unless you have a vastly different product from the ones that have been debunked as "not much", why try to sell it here.

I figure from the last post you made that you in all probability are an employee of the company or perhaps what we might call a spam artist.

Now, if I'm wrong in any way, please set me straight and explain the science behind reflective heat transfer and whatever you base your product on.

thanks.

A Great Place for Information, Comraderie, and a Sucker Punch.

Remodeling Contractor just outside the Glass City.