Solar Shop Heater

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Project by summerfi posted 12-19-2013 11:12 PM 6368 views 29 times favorited 41 comments Add to Favorites Watch
Solar Shop Heater
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I live in a cold climate, and heating my workshop in the winter can be an expensive problem. We’re not allowed to heat with wood where I live due to air quality restrictions. The options are electric or natural gas. I have an overhead natural gas heater in my shop, but it adds a chunk to my utility bill and is also somewhat noisy. Fortunately, the front of my shop faces due south. That got me to thinking maybe I should try to capture some of nature’s free energy.

After researching several solar heating options, I settled on a design similar to this because of it’s simplicity and low cost. The design couldn’t be simpler. It is totally passive, consisting of a transparent panel installed in front of your insulated garage door. The door is raised on sunny days to allow sunshine and radiant heat to come in, and closed at night or on cloudy days to trap the heat inside.

Here are pictures of my version of this heater installed on my shop.

The heater consists of four 48” wide x 8’ tall removable panels. The frame is made of 1x pine that I cut on my small sawmill. The transparent material is clear polycarbonate corrugated panels like are used on greenhouses and patio roofs. The only other materials are some black spray paint, clear caulking, foam weatherstripping, and screws. The 26” wide polycarbonate panels are available from Lowes for $21.62 each. In total, I have less than $200 in the project. In addition, I had previously installed 1 1/2 inches of foil-backed polyisocyanurate foam insulation on the inside of my garage door.

So how does it work? Since installing the heater last Sunday, we’ve had three sunny days. If the sun shines all day, and I open the garage door in the morning, by mid-afternoon the inside temperature has proven to reach 30 to 35 degrees higher than the outside temperature. Right now the temperature outdoors is 25 degrees, and inside my shop it is a pleasant 60 degrees. I’ve not turned the gas heater on all day. The highest temperature I’ve achieved so far was 70 degrees on a day when the high outside temperature was in the 40’s. I anticipate that as days get longer and warmer, I will have to keep the garage door partially closed, or open it only for a portion of the day, to keep it from getting too warm inside for comfortable working.

This is a picture from inside the shop looking out.

In addition to warming the shop, this 8’ x 16’ “picture window” also lets in a lot of light. This should help save on electricity too. Not only does the solar heater warm the body, but it also helps warm the spirits. The bright working environment is much more pleasant to be in during cold winter days than a closed up shop.

While I’ve had this in operation for less than a week, the results I’ve seen so far make me think it’s going to be a big success. When Spring comes, I’ll simply remove the four panels and store them away. They are made to be light and easily moved, and they can be installed or taken down in about 15 minutes.

-- Bob, Missoula, MT -- Rocky Mountain Saw Works

41 comments so far

View Mark Davisson's profile

Mark Davisson

597 posts in 3517 days

#1 posted 12-19-2013 11:53 PM

Bravo! And I’m glad to see you acknowledge how sunlight helps “warm the spirits!” The older I get the more I appreciate the emotional and physical benefits of exposure to sunlight.

-- I'm selfless because it feels so good!

View AandCstyle's profile


3178 posts in 2457 days

#2 posted 12-19-2013 11:57 PM

Bob, that was a great idea and a wonderful project. Would it be possible/reasonable to vent some of the excess heat from your shop to your house?

-- Art

View summerfi's profile


4036 posts in 1887 days

#3 posted 12-20-2013 12:10 AM

Art – Probably not possible to do that with my house, because it sits 100’ away and downhill from my shop. However, it may be possible to vent heat to the second storey of my shop, which right now is just used for storage.

-- Bob, Missoula, MT -- Rocky Mountain Saw Works

View SteveW's profile


396 posts in 3058 days

#4 posted 12-20-2013 01:18 AM

Great project. I’m thinking I need something like that to help heat my shop in the cold weather.
I too have a natural gas heater, and can agree, that it sure can add to the monthly gas bill.
Are those panels polycarbonate that are open at the top and bottom, or did you seal them somehow?

-- On the eighth day God was back in His woodworking shop! SteveW

View john2005's profile


1768 posts in 2378 days

#5 posted 12-20-2013 01:22 AM

Bob, that looks like a pretty slick setup. I also struggle to keep my shop to temp, especially if I am gluing. Kinda wishing it faced south now. Definitely given me something to ponder.

-- In theory there is no difference between theory and practice. In practice there is.

View summerfi's profile


4036 posts in 1887 days

#6 posted 12-20-2013 01:25 AM

Steve – The polycarbonate panels fit inside a wooden frame and are sealed on all sides with clear caulking.

-- Bob, Missoula, MT -- Rocky Mountain Saw Works

View luv2learn's profile


2872 posts in 2503 days

#7 posted 12-20-2013 01:45 AM

What a great way to heat your shop. Good thinking and very nice execution of an idea. Nothing better than free radiant heat. I didn’t know Missoula had winter time burn bans. Half the shops here in North Idaho are heated with wood.

-- Lee - Northern idaho~"If the women don't find you handsome, at least they ought to find you handy"~ Red Green

View Gittyup's profile


150 posts in 2156 days

#8 posted 12-20-2013 02:05 AM

Nice feature you’ve made there.

I saw a solar design on the internet for a shop in Wisconsin. The guy had a south facing wall. He cut slots in the wall between studs about 4” high x 14.5” long, about 5 of them high on the wall and 5 low on the wall. On the outside, he built a simple shall box tall enough to encompass the slots in the wall. The box was lined with black screening, painted black, and covered with clear corrugated panels like the ones here. Supposedly the screening greatly increases the surface area exposed to solar gain. Cool air flowed in at the bottom slots, was heated on both sides of the screening, and naturally convected back into the building. He claimed it kept his shop at about 65 degrees even when 20 or colder outside. At night/in the summer he had swing closed doors to close of the heater. Struck me as a great idea, even if it only partially heated the space. Unfortunately, my south face is into the woods.

-- tel

View Woodknack's profile


12430 posts in 2580 days

#9 posted 12-20-2013 02:59 AM

Amazing that just that much difference in sunlight can make a huge temp difference inside.

-- Rick M,

View hoss12992's profile


4091 posts in 2093 days

#10 posted 12-20-2013 03:34 AM

Great job, and I absolutely love FREE energy from Mother Nature.

-- The Old Rednek Workshop

View oldnovice's profile


7328 posts in 3568 days

#11 posted 12-20-2013 04:32 AM

After seeing this I wish my garage door faced south as this is definitely a simple, efficient, low cost heating system!

I live in San Jose and it doesn’t get nearly as cold as Missoula but I would surely enjoy a 68° to 72° work area in our “horrific” winters.

-- "I never met a board I didn't like!"

View deon's profile


2522 posts in 3225 days

#12 posted 12-20-2013 06:49 AM

Great work!

-- Dreaming patterns

View Ken90712's profile


17594 posts in 3389 days

#13 posted 12-20-2013 09:41 AM

Awesome sounds like it works well.

-- Ken, "Everyday above ground is a good day!"

View Kaleb the Swede's profile

Kaleb the Swede

1876 posts in 2169 days

#14 posted 12-20-2013 12:39 PM

Very smart and very cost effective.

-- Just trying to build something beautiful

View JJohnston's profile


1622 posts in 3491 days

#15 posted 12-20-2013 01:13 PM

Have you done the math to see how long it will take to pay for itself? Probably won’t be long, by the sound of it.

-- "A man may conduct himself well in both adversity and good fortune, but if you want to test his character, give him power." - Abraham Lincoln

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