High-Efficiency Furnace

The furnace accounts for up to 60 per cent of all the energy consumed in the average Alberta house. Switching from an older to a high-efficiency furnace will cost about $5,000, and should cut your heating bills by, on average, about 35 per cent. A provincial rebate is available, click here for more info.	Requires some research. It's recommended you obtain quotes from at least two contractors whose effort depends on what modifications are required to install that furnace.	Replacing an old furnace with an energy-efficient model can reduce your household's greenhouse gas emissions by at least 1.4 tonnes per year.

What is a high-efficiency furnace?

A high-efficiency furnace has an annual fuel utilization efficiency (AFUE) rating of 90 to 97 per cent. In other words, a furnace at the high end of this range will convert 97 per cent of the combusted natural gas to usable energy, with the remaining three per cent exhausted to the outside. By comparison, many older furnaces have an AFUE of only about 60 per cent, meaning 40 per cent of the fuel is wasted.

How do they work?

Most high-efficiency furnaces use a condensing process. Two heat exchangers draw enough heat from combustion gases that moisture in the gas condenses, releasing additional usable heat. The condensate is piped to a floor drain and exhaust gases are cool enough to be vented out a sidewall with a four-inch piece of plastic pipe, thus eliminating the need for a chimney. Because the combustion in these furnaces is sealed, there is also no risk of carbon monoxide leaks.

Why should I buy a high-efficiency furnace, isn't a mid-efficient one good enough?

You can buy a mid-efficiency model (78-84% AFUE rating), but mid-efficiency furnaces are up to 19 per cent less efficient than a high-efficiency model and thus will increase your operating costs and greenhouse gas emissions. Depending on what model you buy and the amount of vent piping required, a high-efficiency furnace can cost about a third more to buy and install than a mid-efficiency model. Be aware that Natural Resources Canada has announced that, as of December 31, 2009, all new furnaces must have an AFUE rating of at least 90 per cent..

Is it difficult to install a high-efficiency furnace?

Because of the increasing popularity of high-efficiency furnaces in Alberta, a sizable number of contractors now have considerable experience installing them. The layout and space considerations of your house will dictate what ductwork is required. For example, most high-efficiency furnaces are vented, by a four-inch pipe, to an outside wall and combustion air is drawn in through plastic pipes.

Will I notice any difference in the heating of my house?

A high-efficiency furnace runs quieter than a mid-efficiency furnace and should make your house more comfortable with its ability to maintain a more constant temperature. You may notice it cycles on and off more often, but for shorter time periods, than your old furnace.

What size should my high-efficiency furnace be?

Size is determined by the total building envelope heat loss, therefore a heat loss calculation should be done to accurately determine size (available from heating contractors). Quite often high efficiency furnaces are being installed that are too big for the actual heating requirements. An experienced contractor can properly size your new furnace. A high-efficiency model can generally be somewhat smaller, in BTU input, than an older or a mid-efficiency furnace.

The size of furnace you'll need will be affected by the level of insulation and air tightness of your house. So it makes sense to plug those heat leaks and perhaps upgrade your insulation (especially under the roof, where you can get the most bang for your buck) before investing in a new furnace. By contrast, a too tightly-sealed house can affect air quality. Installing a fresh air intake or mechanical ventilation system will bring in and circulate fresh air, without causing drafts or heat loss.

How do I know the furnaces I'm looking at are high-efficiency models?

All high efficiency furnaces meet ENERGY STAR® standards and therefore will have an ENERGY STAR symbol on the furnace, on the packaging or promotional material. An EnerGuide label will indicate the furnace's efficiency percentage.

Should I consider getting a variable-speed motor to run the fan of my new furnace?

Yes. Although the cost of a direct-current, variable-speed motors is higher, the electricity consumption will be at least 30 per cent less than with a conventional motor.

A variable-speed motor is a high-efficiency motor due to the precise electronic controls allowing it to operate efficiently at any speed. A standard AC motor's efficiency, on the other hand, drops off dramatically at lower speeds. Lower speed operation of the variable speed motor thus delivers savings, runs quieter, and provides more even temperature control throughout the home adding to occupant comfort.

How can I find a qualified installer for a high-efficiency furnace?

Check the Heating, Refrigeration and Air Conditioning Contractors of Canada website for a listing of local contractors qualified to install high-efficiency furnaces. Get estimates and references from at least two experienced installers and ask for a heat loss calculation, used to determine the size of furnace needed.

How much maintenance does a high-efficiency furnace require?

A high-efficiency furnace should require no more maintenance than any other type of furnace. An annual maintenance check will help ensure your furnace is operating safely and at peak efficiency.