Welcome to our series answering reader questions and concerns about how to cut the utility company cord.
I currently use wood to heat my off-grid home but would like to figure out my options for using solar power (with batteries) for home heating. I assume the first step would be to determine solar’s cost-effectiveness for heating, but the process feels overwhelming. Can you suggest a few initial steps to get me started?-Lori Johnson
I’ll assume your intent is to heat your home with an off-grid system, since you mentioned using batteries. If you’re thinking about converting your heat source from wood to battery-banked electricity, you’ll find that approach to be the most expensive – and least reliable – way to heat your home.
In my experience, it’s impractical to use solar and batteries as a heat source. Electricity has historically been more expensive than other options and can fail during storms. Batteries are the most expensive components of off-grid systems: Even with solar panels to charge them, you must have enough stored energy capacity to cover your electricity needs for several days. In the event of an unusually long, cloudy period, you might also need to include a generator.
Instead, off-grid homes tend to use wood or propane for space heating (and sometimes solar for heating water), saving electricity to operate fans. I’ve also seen nice setups producing radiant heat using a Franklin stove or a fireplace. Whenever you depend on solar-plus-storage systems, you must first address all energy hogs. At the top of the list are air conditioning and heating. You’ll want to add plenty of insulation and eliminate drafts.
So, do you have alternatives to wood? Yes, a few, and their viability will depend on where you live.
The Air Force base in Fairbanks, Alaska, where I lived had a coal-fired generator for power, and the base piped steam through turbines and circulated heat throughout the campus. On a smaller scale, many people off-base had hot-water heat that used fuel oil to fire boilers. The old “sourdoughs” who carved a homestead out of the Alaskan wilderness used traditional wood heaters or fireplaces. In the desert Southwest, where nights are chilly and days are warm, traditional homes are built to take advantage of solar gain in the daytime using 18-inch-thick adobe blocks that radiate heat back out at night.
Now I live in Texas, and I invested in insulation to keep my home cooler in summer and warmer in winter. I open windows on the first and second floors to move air. I also borrowed an idea from Alaska by adding an insulated storage room called a “wanigan” between my garage and the rest of the house that acts as a barrier between the cold outside and the heated interior of the home. My heat source is fossil (“natural”) gas, and I also have multiple air handlers with zones that can be individually controlled. In case the electricity goes off for a long period of time, I have both a gas-burning fireplace and a woodburning one.
For your situation, I’m not saying heating your house with solar and batteries can’t be done, but in my experience, it would be the costliest approach and, in fact, the riskiest. You only have a limited amount of stored energy, and after it’s used up, you’ll be left in the dark and cold! Even if you decide to go with one of the alternative heat sources, I recommend you keep your wood heat as a backup.
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May all your days be filled with sunshine – even when it rains!
Hoss Boyd is founder, president, and CEO of TeraVolt Energy and a recognized solar and energy-storage expert.