How to heat your house when the power goes out?
As it becomes painfully clear during an extended mid-winter power outage, most heating appliances rely on electricity in some way. It’s not just electric furnaces, baseboards, or space heaters–which convert electricity directly into heat. Oil-fired and gas-fired furnaces, boilers and space heaters also rely on electricity, even though they produce heat by burning other fuels. Boilers use pumps to carry heated fluid away from the combustion chamber to the home’s hydronic distribution system; furnaces similarly use fans to carry heated air to the duct distribution system. Their control systems also require electricity.
Even alternative energy sources, like heat pumps and solar thermal panels, use power to transfer heat from one place to another. Solar thermal panels require electricity to run pumps that transfer heated fluid from the panels into a storage tank, and then to pump the fluid back to the solar panels. Heat pumps use electricity to run a refrigeration cycle that transfers heat from the ground or air into a home.
So where does this leave you in the event of a power outage? In Fairbanks, the local utility strives to prevent power outages and fix them quickly when they do occur, so an electricity-free appliance is not a complete necessity. However, in a climate like Fairbanks it’s a good idea to have a backup that’s not contingent on the grid.
Most such appliances involve firewood. Wood stoves operate without any electricity: simply load dry firewood into the firebox and light. They don’t distribute heat through ducts or a hydronic distribution system, but simply radiate heat into the home. [Wood-fired boilers or hydronic heaters, which can distribute heat to a distribution system, need electricity to power pumps.] Another option is a masonry heater, which is much larger and heavier than a wood stove. The flue in a masonry heater snakes through a heavy mass of rock or brick, which absorbs energy from hot flue gases and radiates it slowly into the room. Their slow release of radiant heat means they can keep the house warm for a day or more on one firing cycle.
Pellet stoves are relatively new in comparison to wood stoves and masonry heaters. Most models are controlled by a programmable thermostat and use electricity for automated operation, however some don’t require electricity, like the gravity-fed versions made by Wiseway Pellet Stove in Oregon. Also, many pellet stove manufacturers now include a battery backup that allows the stove to operate for up to 24 hours without electricity.
There are a limited number of gravity-fed oil combustion heaters that do not require electricity, but they are not very common. In the past they were called “drip stoves” and were not considered a very safe appliance.
Finally, if you are building or retrofitting a home, consider two methods that will keep you warmer during a power outage that have nothing to do with your heating appliance. First, more insulation on the envelope of the house will allow less heat escape. So if you don’t have a wood-burning appliance, at least you won’t freeze up as quickly. Second, many houses are designed with passive solar heating elements such as south-facing windows or sunspaces, or a large mass such as a concrete floor that can absorb heat from the sun during the day and then release that heat at night. While these techniques are generally not able to heat an entire home, they can provide supplemental heat throughout the year.