Insulating my garage door has been on my list of things to do for a couple of years. We live in the high desert so experience mild winters, with a few snowy days and some days with sustained 60 mph winds, and deathly hot summers, when every day is sunny with some days of sustained 30-40 mph winds. Spring and Fall amount to about 10 days per “season” with mild temperatures and a bit of rain. It’s not unusual to experience temperates of 32 degrees (Fahrenheit) or 100 degree – in a single week – so garage door insulation should really have been a higher priority, as the temperature of an attached garage can have a significant effect on the house it’s attached to.
As with many “to do” items, garage door insulation had slipped into the “maybe I can get to this someday” bucket. Well, I finally got around to it – and the reason is because about two weeks ago I stumbled across a great article (here’s a link) about someone insulating their garage door for about $50. This is a great price, but the best part (for me) was that the insulation they used could easily be bought at the local home improvement store and thrown in the back seat to get it home. In other words, no truck or delivery needed, which is a big deal for me, as I currently have a very small car and no truck.
The person who wrote the article used a product that is normally meant to wrap around heating and cooling ducts. It’s the metallic looking stuff that’s shiny on both sides and has small bubbles. Usually, people refer to it as metallic bubble wrap and that’s just what it looks like, except it’s not as thick as most bubble wrap. Mostly, it’s from between 3/16 inch thick and 5/16 inch thick, which is a little less or a little more than 1/4 inch thick (6.35 mm).
Hey, guess what else looks like this stuff? Those sun shade things you put up against the inside of your windshield to keep the sun from killing the inside of your car. And … you can get sun shades at your local 99 cent / dollar store! A single one of them is almost perfect for each little cubby of the average metal garage door.
Granted, these are not quite as hefty as the duct wrap, but I was able to use two layers in each cubby which makes the R-value even higher than the R-6 the duct wrap I compared at Home Depot is rated.
Tools you will need
- Sharpie (optional)
- Pair of scissors
- Yardstick or some other straightedge (optional)
How I did it
1. Took the sun shade out of the package
2. Put it vertically up against the garage door section and did an “eyeball” measurement to get the needed height (my garage door sections are all roughly 21 inches tall)
3. Marked it for cutting with a Sharpie (just for the first few, then I just used a cut-off piece as a guide and cut the rest of them by “eyeball”)
4. Cut off the extra height (and cut off the little pieces of elastic meant to keep the sunshade folded up all nice when not in use)
5. Unfolded the sun shade and poked it into the garage door section (so the sun shade fit snugly into the garage door section). The sun shade fit the larger section just right as far as width. I cut half of the sun shades at the first fold from one end to shorten the width for the eight smaller (45 inch wide) garage door sections.
6. Repeat steps 1 – 5 for the other 8 (single car garage door) to 16 (double) garage door sections
7. Repeat steps 1 – 6 if you are using two layers
At first, I had planned to do a single layer, and that probably would have been adequate to provide some insulative value – and the cost to do the whole two-car garage door would have actually been ONLY $16 (not including tax). But, then I thought, what the heck, this was so easy to do that I picked up 16 more of them on the way home from work the next day and doubled the layers, for a total cost of $34 and some change – still a savings of at least $18-$20 over the duct insulation method.
For the second layer, I flipped the sun shade upside down from the first layer. This was due to the fact there are two grommets (and small holes) in each of the sun shades. These grommets were meant to hold the little suction cups that come with the sun shade to help it stay in place up against a windshield. Since the sun shade was flipped from the first layer to the second, the grommets (and therefore holes) didn’t line up.
That’s All There Is To It
That’s it. Don’t make it harder than it has to be. No need to tape them in or attach them in any way. Most metal garage doors have enough of a “lip” on each section to easily hold the insulation / sun shade in – even when the garage door is in the open position. As a matter of fact, I’m sure it’s better for the R-value if you let the stuff “float” in there. I’ll let that advice ride unless some engineer-type comments that it should be otherwise.
NOTE : If you plan to measure one of the garage door sections and cut all of them to the same size, you will not be a happy camper when you try to install them, as not all of the sections are the exact same size. At least measure each “column” of sections to get an accurate size before doing any cutting on the sun shades. The sections on my door were approximately 45 inches by 21 inches for half of them and about 51 inches by 21 inches for others.
The difference in temperature on the inside surface was about 20-25 degrees (Fahrenheit) lower with the insulation. The difference in the actual temperature in the garage was, of course, much less – about 73 degrees at 1:00 in the afternoon with outside temperatures of 80 on Saturday – before the insulation was installed. On Sunday, the outside temperature was 81 degrees at 1:00 in the afternoon and 68 degrees in the garage. Not a huge difference, but even a couple of degrees can make a noticeable difference in cooling (and heating) bills.
So, the garage door insulation was done with two layers of the sun shades for a total of $34.21 ($31.68 for 32 sun shades at the 99 cent store plus $2.53 sales tax). I didn’t figure anything in for gas, as the 99 cent store is only about 2 blocks out of the way on my way home from work.
If nothing else, I hope this inspires at least a couple of people to look at materials in a different way and realize it’s not that expensive to make your house more efficient.
Cost and installation comparison for a standard metal 2-car garage door
Sun Shades (my guess is R-6 up to R-8) $0.99 per sun shades x 32 = $34.21 (including state tax)
- hardest part is finding 16 – 32 sun shades at your local 99 cent store
- took about one hour total to unpackage, cut, and install the shades
- only tool needed to install were scissors
Garage Door Insulation Kit from (R-8) $79.99 x 2 = $159.98 (2 kits required for 2-car garage door)
- these kits are just standard “batt” type insulation pre-cut into pieces that will fit most metal type doors
1″ insulation board (R-6) $19.95 per sheet * 4 sheets = $79.80 (priced at Home Depot 2015)
- insulation board would have to be cut into pieces (or at least scored and bent) to get it to span corner to corner in each section
- estimated project time would be at least a few hours
- might require glue to stay put (some instructions we found said to glue, some didn’t)
- foam board is 4 foot by 8 foot so you would either need a truck to get it home or have to cut it (fairly accurately) in the parking lot of wherever you bought it
Duct Insulation Wrap (R-6) – 7 rolls @ $36.95 = $258.65 (before tax for two layers)*
- 24 inch x 10 feet by 5/16 inch thick
- probably no more than an hour to install, but 24″ wide material would have to be cut to height
- tools needed to install would be scissors and a yardstick
We were not able to find duct insulation that was anywhere near as cheap (~$25 a roll) as the woman who wrote the original post about this. Either the duct wrap we found was way too small or a lot more expensive.