High-efficiency gas most affordable option

Heat pumps most energy efficient

With heating accounting for about 60 per cent of energy use in a home, it's no wonder homeowners want to be up to date on the most economical options.

While there are a number ways to heat a house, choosing the right system often comes down to budget and the house itself.

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Houses built prior to about 1950 often had hot water (hydronic) heating systems, with boilers supplying hot water to cast-iron radiators. Houses built after 1950 commonly used forced-air systems that distributed heat throughout a house via a system of ducts.

For either of these scenarios, a gas furnace is the most economical choice.

"Go for a high-efficiency furnace," recommends Rob Barry, an applied science technologist and president of Island Energy.

"The capital cost for a gas furnace is low and the cost of the fuel is expected to be stable for the next 10 years."

Gas furnaces typically have a lifespan of about 20 years. He suggests homeowners start considering replacing a gas furnace after 15 years, as maintenance costs start to increase. A new furnace costs about $4,500.

Homeowners with existing gas furnaces looking to lower their energy bills might consider adding an air-source heat pump to their systems.

"Heat pumps are the most efficient way to heat a home," says Marshall Mason, a technician with Accutemp Refrigeration, Air Conditioning and Heating, who has been installing heat pumps around Victoria for the past six years.

"While you get a dollar of heat out of every dollar of energy in a baseboard heater, you get four dollars of heat out of that same dollar in a heat pump."

Heat pumps operate by extracting heat from the outside air. They are less efficient when the temperature drops below freezing, when a back-up system using conventional fuel may be needed. In summer, they reverse operation, supplying air conditioning in the heat of the day.

A heat pump's only energy use is power to run coolant fluid through the system and a blower fan.

In many retrofits, a heat pump is added to an existing forced-air furnace. But Barry cautions that electric-fan motors on older furnaces might have a harder time with a new heat pump. He says heat pumps drive existing fans hard, causing accelerated wear and increased noise. New electric fans, with continuously variable speeds, are better matched to heat-pump operation, as well as quieter and more energy-efficient.

Heat pumps also need a backup energy source for those days when they struggle to extract enough heat from the air. The back-up fuel can be natural gas, electricity, propane or even oil.

An air-source heat pump can cost between $5,000 and $10,000. Homeowners can apply for a number of financial incentives.

Geothermal, a ground-source heating system, is 50 per cent more efficient than its air-based cousin. A geothermal heat pump extracts heat from underground, or sometimes from water. This requires either a bore driven into the ground, or laying out a field of pipes around a house.

This extra complexity means the cost of geothermal systems starts at $20,000. Installation costs can rise depending on the soil encountered around the property - for example, if diggers encounter rock. The geothermal field can also be arrayed underwater if the house is near shoreline.

Geothermal is a viable option if the annual heating bill of a large house is between $3,000 and $5,000 for oil, said Barry.

"That bill will be replaced by an annual electric tab of around $1,500. The system will pay for itself in 10 to 12 years."

People considering either system would be wise to check their electrical panels. Typically, installing a heat pump would trigger an upgrade to a 200-amp service. An upgrade in electrical service can cost about $3,500.

But not everybody is on gas, nor comfortable with a heat pump. For them, a wood-burning stove may be the answer.

"We sell a number of wood stoves, primarily to outlying rural areas," said Eric White, an estimator at Ark Solar. "For them, it can be a primary or an emergency source of heat."

While a cord of wood can cost between $180 and $200, he says people in rural areas have more access to cheaper - and even free - lumber from a variety of sources. They typically also have the room to store and dry the firewood.

A good wood stove costs around $4,000.

Forget about turning to the sun as an alternative to heat a house. The solar systems available are typically used to heat domestic hot water only.

"Unfortunately, there's not a lot of solar potential between October and March around here," White said.

parrais@timescolonist.com

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