I have always wanted a space of my own to work on my varied and numerous projects—everything from painting to furniture restoration to various excuses to use all of my power tools. A need to store work equipment and tools helped push me to action, so three years ago I finished half of my detached two-stall garage in order to create this space.
Introducing the Shopfice
I super-insulated the walls and attic and added a patio door inside the garage door to create a weather-tight envelope that lets lots of light in, but was camouflaged as a mild looking garage when not in use. It was a fun project, and one I loved the results of. I work much of the time from home, and started spending many of my days working in what I began to call my “Shopfice.”
My first attempt at renewable heating
I also installed in my Shopfice the smallest and most efficient freestanding woodstove I could find. When that first winter set in, I got up early each morning and ran out and started a fire so the Shopfice would be warm enough to work in by the start of the workday. No matter how small I made the fire, I was way overheated by 9:30 and had to leave the door open. Not exactly what I had in mind. I tried and tried to get the hang of keeping a small tightly insulated space comfortable with wood, and largely failed to do so. Then I heard from my insurance adjuster and discovered our home insurance was going up $300 per year because of the presence of the wood stove. Ouch. I bowed my head in defeat and disconnected the wood stove. In its place I used an electric space heater. I am an energy auditor by trade, and since electric space heaters are possibly the most inefficient and expensive way to bring warmth to a space, I cringed every time I turned it on.
Heating with solar
This summer I opted instead to install a simple solar air heat (SAH) system on the shop. These are systems that when called for take air from a heated space, pull it into the solar collector, and return warmed air back into the space. The cost of the single 8’x4’ panel SAH system was about the same cost as running a natural gas line and installing a small gas heater, $4,000. This system has not been through a winter yet, but my calculations predict the SAH system will produce enough heat so that my space heater set at 45 degrees will never—or very rarely—need to kick on. I will still likely need to use the space heater for spot heating at times.
Solar air heat system on Sarah Hayden Shaw’s “Shopfice.”
Cost savings
In previous years the cost to run the space heater has been about $300 per year, and I anticipate the SAH system will eliminate 75% of the space heat load, so it can be valued at $225 per year. I will receive a Made in Minnesota Rebate (MIM) because I purchased a system manufactured here in Minnesota, as well as a 30% federal tax credit. The gas heater would have had no incentives and higher ongoing operation cost, so in comparing the two, the SAH system makes much more sense financially.
Here is how the numbers bear out for simple solar air heat (SAH):
- Cost: $4,417
- MIM rebate amount: $1,104.25
- Federal tax credit amount: $1,325.00
- Total cost: $1,987.65
- Annual savings: $225.00
- Payback: 8.8 years
Alternately, replacing the electric space heater with a gas heater would have the following finances:
- Cost: $4,000.00
- Rebates: $0.00
- Annual savings: $150.00
- Payback: 26.7 years
Although 8.8 years is a respectable payback, if money alone was the factor, it might have been tempting to just keep blasting my $68 space heater, but in addition to my extreme aversion to wasting energy, safety also factored into my decision, and leaving an electric space heater unattended doesn’t sit well with me. Clearly the gas furnace is not a financially smart way to go.
Sunny summary
This has been a fun project, allowing me to look for creative ways to use less energy. I look forward to a toasty warm, guilt-free winter this year in my Shopfice! Drop me a line if you are in Brainerd and want to come see it in action!
