What a heater has to do

In lesson 30 you estimated your heat loss. A heating system has one job: replace that heat, hour after hour, on the coldest nights.

Every option has three parts to think about:

• The fuel or energy: electricity, wood, pellets or propane. Where does it come from, and what does it cost?
• The delivery: a stove in one room, ducts, or small heads on the wall. Does heat reach the bedrooms?
• The exhaust: anything that burns fuel makes smoke or combustion gases. They must leave the house safely.

A tight, well-insulated small home makes every option cheaper and easier. That is the main lesson of this track.

Heat pumps: moving heat instead of making it

A heat pump uses electricity to move heat from outdoor air (or the ground) into the house. It works like a fridge running in reverse. In summer, most heat pumps can also cool.

Because it moves heat instead of making it, a heat pump can deliver more heat than the electricity it uses. That ratio is the coefficient of performance (COP). A COP of 3 means 3 kWh of heat for each 1 kWh of electricity.

COP falls as the outdoor air gets colder. Cold-climate heat pumps are built to keep working well below freezing, but output and COP still drop on the coldest nights (DOE). Many systems have backup heat for those hours.

Off the grid, a heat pump’s winter electric use lands when solar output is lowest. Size the solar and battery for January, not June.

Electric resistance: simple, but costly to run

Electric resistance heat turns electricity straight into heat, as in baseboard heaters, wall heaters and plug-in space heaters. Its COP is 1: one kWh in, one kWh of heat out.

It is cheap to buy and install. It is expensive to run for a whole winter in most places. Off the grid, it is rarely practical as the main heat source.

Space heaters cause about a third of US home heating fires and most heating fire deaths (NFPA). Keep anything that can burn at least 3 feet (about 1 m) away (US Fire Administration). Plug them straight into a wall outlet, not an extension cord. Turn them off when you leave the room or go to sleep.

Wood and pellets

Wood is the classic homestead heat. It can come from your own land, but it is real work.

• Burn only seasoned wood: wood split and dried until its moisture is below about 20% (EPA Burn Wise). Wet wood gives less heat and more smoke.
• A modern EPA-certified stove burns cleaner and makes less smoke than older stoves.
• Creosote is a tar that builds up inside chimneys, faster with wet wood and smoldering fires. It can cause a chimney fire. NFPA advises a yearly chimney inspection, with cleaning as needed.

A pellet stove burns small pellets of pressed sawdust from a hopper. It needs less tending, but it needs electricity for its fan and feed, and you must buy and store pellets.

Propane

Propane is a gas fuel stored as a liquid in a tank on your property. It runs furnaces, wall heaters, water heaters and stoves, and it works without much electricity.

• Vented or direct-vent heaters send exhaust outside through a pipe. A direct-vent unit also draws its combustion air from outside.
• Unvented heaters release their exhaust into the room. DOE does not advise them indoors, because of the carbon monoxide risk. Some states and towns ban them, and codes often bar them from bedrooms and bathrooms.

Propane prices swing with the season and the market, and you rely on delivery. Gas lines, tank placement and appliance connections are licensed work. If you smell gas, leave the building first, then call for help from outside.

The cold-weather bill

Fire, smoke and carbon monoxide

Anything that burns fuel makes carbon monoxide (CO), a gas you cannot see or smell. It can make people sick or kill them, often while they sleep (NFPA).

• Put CO alarms on every level and outside sleeping areas. Put smoke alarms in every bedroom and on every level (NFPA). Test them monthly.
• Never use a grill, camp stove or generator indoors for heat.
• Keep stoves, flues and chimneys inspected, and keep anything that burns a safe distance away.

These are not rare edge cases. Heating equipment is one of the leading causes of US home fires (NFPA).

Compare the options

Many homesteads use two sources: one main system and one backup that works if the power or fuel runs out.

Check

Summary

• Every heating choice trades off running cost, labor, power use and risk.
• Heat pumps move heat. Their COP is heat out per unit of electricity in, and it falls in deep cold.
• Wood is cheap fuel and hard work. Burn seasoned wood and keep the chimney inspected.
• Anything that burns fuel needs a safe vent, working CO and smoke alarms, and a licensed installer.

Next, you will look at keeping cool with as little power as possible.