Feb 3, 2009
Heating your home
Heating your home
Feb 3, 2009
Heating your home
It’s better to investigate replacement solutions before your furnace kicks the bucket, so here’s a look at the most common heating systems available in Canada.
Two-thirds of all Canadian homes are heated with forced-air furnaces. Of these, two-thirds are fired by natural gas, while the rest are fired by oil or propane. These systems are popular for a number of reasons, notably their ability to heat the house quickly and the fact that their ductwork can also be used for air conditioning during the summer months. In addition, a forced-air furnace can be equipped to multi-task as an air filter, humidifier and/or fresh-air ventilator. The downside of forced-air systems is that it can feel drafty because of the air blowing out of the vents, which also may circulate dust. Ducts can carry noise from the furnace and blower throughout the house. If your furnace is more than a dozen years old, chances are it’s a conventional model with an annual fuel utilization efficiency (AFUE) of only 60 to 65 percent. This means that for every dollar you spend on fuel, 35¢ to 40¢ goes up the chimney in the form of exhaust gases. Since 1995, the minimum efficiency level for furnaces sold in Canada has been set at 78 percent.
Currently, there are two types of furnaces on the market. The first type is called “mid-efficiency,” and they are models that are about 80-percent efficient. These units have a combustion chamber located below a heat exchanger that warms air that the blower circulates through heating ducts. The lighter-than-air combustion gases are expelled through your chimney. The second category of furnaces are known as "highefficiency" or “condensing” and range from 90- to 98-percent AFUE. A condensing furnace is a regular furnace with a builtin heat recycler that draws the maximum amount of heat from the flue gases before they exit through the chimney. In the process, these gases cool to the point that they condense – thus the name.
The price of a mid-efficiency furnace for a typical home may be about $1,000 cheaper than a comparable highefficiency model, but you can only make an accurate cost comparison by calculating the operating expenses over the lifetime of the furnace – typically 15 to 20 years. A 10-percent difference in your monthly gas bill can quickly add up to the initial price difference between the two, particularly if fuel prices rise.
More research and development goes into forced-air furnaces than other heating systems (a result of their market dominance) so they benefit from the most technological advancements. Some innovations are now standard, such as electric ignition, which has long since replaced pilot lights. Other refinements get bundled in as you move up the price list of new furnaces.
A standard furnace has a single-stage gas valve. Every time your furnace turns on, it runs at peak capacity. The alternative is to upgrade to a two-stage valve, which enables your furnace to “think like a small furnace,” says Dave Walton, director of home ideas for Direct Energy. Two-stage furnaces run in low gear the majority of the time. They only kick into the second stage on the coldest days. This allows the system to run longer heating cycles at, typically, half the total capacity of the furnace and prevents temperature swings, providing better comfort and efficiency to the system.
Another upgrade is the variable-speed fan blower, which runs at a lower speed almost continuously, thus reducing energy consumption and noise. The variable-speed fan will do the same job for your central air conditioner.
Electric heat is the second most popular option in the country. More often than not, electric heat is generated in baseboards and in recessed floor- or wall-mounted heaters. It’s unique in that it is considered to be 100-percent efficient – all the energy consumed by the heaters is converted to heat.
For homeowners, the big draw to this form of heating is the low initial cost of the system. You can buy a thousandwatt baseboard heater with enough power to heat a small room for less than $40 and the price increases with sleeker, space-saving designs and enhancements such as circulating fans. A general guideline is that you need eight to 10 watts per square foot.
If you’re considering electric heat, you should take longterm operating costs into account. Depending on the size and condition of your house, heating electrically can cost hundreds of dollars a year more than running a mid- or highefficiency natural-gas furnace. That said, electric heat can be a cost-effective, supplemental system, and it can also provide enhanced comfort, as is the case with electric heating cables installed beneath bathroom floor tiles.
Hydronic heating systems use hot water or steam to provide warmth. In older urban homes, this usually includes a boiler with hot-water radiators in each room. While the basic equipment has not radically changed over the years, there has been some technological advancement. More efficient fuel pumps and burners, automatic dampers and circulating pumps have boosted boiler efficiency levels from around 60-percent AFUE to a current minimum of 80 percent for models sold on today’s market.
The machinery is changing too. Condensing boilers with a secondary heat exchanger (and an AFUE of up to 95 percent), popular in Europe, are now available in Canada. Smaller, baseboard-style radiators that take up less living space than the old cast-iron units are also gaining popularity. One form of hydronic heating that is becoming more popular is floor radiant heating. With this type of system, a boiler or hot-water tank warms the water that runs through pipes that have been installed beneath the floor. You can heat an entire house this way or use it to supplement your existing system to provide additional warmth in selected rooms, such as the kitchen or the bathroom.
The bottom line
If you do need to change your heating system, cost will probably be a major consideration. The federal government ecoENERGY program (www.oee.nrcan.gc.ca) offers homeowners thousands of dollars in rebates for undertaking energy efficiency renovations (including up to $500 for upgrading your furnace). The program is supplemented in Ontario with a matching dollar-for-dollar provincial government Home Energy Retrofit Program. Various utilities also offer rebates and incentives on, for example, the installation of a programmable thermostat.
- Maintaining a humidity level of 35 to 45 percent inside your home reduces static buildup, moderates shrinking and swelling of wood floors and prevents dry skin and a scratchy throat. Whole-house humidifiers that are mounted on a furnace can be either passive (when the air passes through a water-filled filter) or active (when a fan forces air through a water-saturated pad). Both styles require occasional cleaning and an annual replacement of the evaporator pad.
- Forced-air furnaces come equipped with only a one-inch thick air filter. For optimal air quality (and to protect the secondary heat exchanger on condensing furnaces), upgrade to a mechanical or electronic air cleaner.
- Unlike theirdrafty, elderly neighbours, new energy-efficient (R-2000) homes require a mechanical ventilation system that exchanges stale air for fresh air. A heat recovery ventilator (HRV) recycles heat from the exhaust air to warm the incoming fresh air, reducing the overall energy demand.
- Setback thermostats can be programmed to lower the temperature while you’re asleep or at work and raise it back up to your comfort level before you get out of bed or back home. Natural Resources Canada estimates a two-percent saving on your heating bill for every degree you lower the heat.