Just another random thing I'm considering

I know... I said no more big projects. BUT we have this slight problem of an uninsulated garage door. So tonight I set out on a quest to find something effective and cheap-ish.
The problem with the garage is that Alex's room is right above it. The garage gets HOT, so Alex's room is usually pretty warm. I run a small fan in there in addition to his ceiling fan during his nap.
I feel like our air conditioner has to work a little harder to keep the upstairs cool.
Likewise, it is much colder in the winter as well. We use a space heater in there during the winter and dress him in warm jammies because he doesn't keep blankets on.

Of course, all solutions can be found on the internet. The end result is that I want to line our attic with solar reflector and stick some duct insulation on my garage door panels. I was thinking that the solar reflector stuff would even work on the garage, but the duct insulation actually has a small R value to it (3), so it may work better. I could double layer it for it to do more good.

The question is, would doing the above 1-save me enough money to make it worth it for the next 8ish months that we live here and 2-make the house more marketable? Is that something that most people would see as a perk above other houses?