A guide to household heating
What are your options when your heating system calls it quits?
”That's not good” is precisely the kind of thing I didn't want to hear the technician say when he was in the middle of the annual cleaning and inspection of my heating system. “Your tank is leaking. I'm going to have to red-tag it,” he said, wiping his oily hands on an even oilier rag as he explained the problem.
With a red tag on the inflow pipe, the oil company wouldn't fill up the tank on their next scheduled visit. Eventually it would run dry and the boiler wouldn't be able to heat the water that runs through our radiators. With fall fast approaching, we had no choice. Something had to be done to fix the problem. But we did have plenty of options: we could replace the tank and upgrade our inefficient, 70-year-old boiler with a newer model; we could eliminate the need for an oil tank by converting to a natural gas boiler, which would be relatively easy since we already had a gas line for hot water; we could rip out the rads, boiler and oil tank, then replace everything with electric baseboard heaters; we could even install ductwork for a forced-air furnace, although that's a task not many steps removed from gutting the building.
My hydronic system with the leaky oil tank put me in the minority, but here's a look at the more common heating systems available on the Canadian market and the bells and whistles you can add when it comes time to replace your heating system.
A lot of hot air
Two-thirds of all Canadian homes are heated with forced-air furnaces; of those, two-thirds are fired by natural gas, and the remainder by oil or propane or heated electrically. These systems are popular for a number of reasons, primarily their ability to heat a house quickly: turn up the temperature on your thermostat, and seconds later warm air comes blowing out of the registers. The ductwork can also be used for air-conditioned cooling in summer, and a forced-air furnace can easily be equipped to multi-task as an air filter, humidifier and/or fresh-air ventilator. On the fuel side, the gas line required for a gas-fired furnace will also provide fuel for your stove and barbecue, heat your hot water, and even supply a warm, soothing fireplace with the flick of a switch.
On the downside, the air blowing out of your vents can feel drafty and may circulate dust. The ducts can also carry noise from the furnace and blower throughout the house.
If your current furnace is older than your VCR, then it's probably a “conventional” model that has an annual fuel utilization efficiency (AFUE) of only 60 to 65 per cent. What that means is that for every $1 you spend on fuel, 35¢ to 40¢ goes up the chimney as waste exhaust gases. Since 1995, the minimum efficiency level for furnaces sold in Canada has been 78 per cent.
Today, there are two furnace types on the market. The first are the “mid-efficiency” models that are about 80 per cent efficient. Simply put, these have a combustion chamber below a heat exchanger that warms the air the blower circulates through your heating ducts. The lighter-than-air combustion gases vent through your chimney.
Furnaces in the second category, known as high-efficiency or “condensing” furnaces, are 90 per cent efficient or better. Think of a condensing furnace as a regular furnace with a built-in heat recycler. “A condensing furnace has a secondary heat exchanger,” says Ed Seaward of Union Gas in Toronto. The additional heat exchanger “draws the maximum amount of heat out of the flue gases before they exit the chimney.” In the process, these gases cool to the point that they condense, thus the name. The resulting water drains through the floor and the remaining gas is vented through a horizontal pipe in an exterior wall.
Although the sticker price on a mid-efficiency furnace for a typical home may be $1,000 or so cheaper than a comparable-sized high-efficiency model, you can only make an accurate cost comparison by calculating the operating expenses over the lifetime of the furnaces–typically 15 to 20 years. A 10 per cent difference in your monthly gas bill can quickly add up to the initial price difference between the two, particularly if fuel prices rise.
As a result of their market dominance, more research and development goes into forced-air furnaces than other heating systems, and so they benefit from the most technological advancements. Some innovations, such as the electric ignition furnace, which have long since replaced pilot lights, are now standard. Other refinements get bundled in as you move up the price list of new furnaces.
A standard furnace has a single-stage gas valve. “When there's a call for heat, the whole valve opens and you get full capacity going into the furnace,” says Ted Patterson, technical standards manager for Direct Energy in Toronto. In other words, every time your furnace turns on, it's running at high gear.
The alternative is to upgrade to a two-stage valve. Two-stage furnaces run in low gear the majority of the time. They only kick in to the second stage on the coldest days. “It allows the system to run longer heating cycles at, typically, half the total capacity of that furnace. This allows it to have a constant stage of heating so you don't have temperature swings. It equals better comfort and better efficiency for the system,” explains Chad Johnson, senior product manager with U.S.-based manufacturer Carrier.
A second upgrade is a variable-speed fan blower. These fans usually run at a lower speed almost continuously, and thereby reduce energy consumption and noise. Another advantage of a variable-speed fan is that it will do the same job for your central air conditioner.
Finally, not unlike cars, as furnaces incorporate more complex technology, diagnosing problems becomes increasingly difficult. Higher-end furnaces now come equipped with self-diagnostic systems that point technicians in the right direction, but it's not easy for homeowners to isolate problems themselves.
Electric heat is the second most popular heating option in the country, with the highest concentration in hydro-rich Quebec. Natural Resources Canada estimates that 60 per cent of homes in la belle province are heated electrically.
A small percentage of forced-air and hydronic systems are electrically powered but, more often than not, electric heat is generated in baseboards and recessed floor- or wall-mounted heaters. Electric heat is unique in that it is considered to be 100 per cent efficient–all the energy consumed by the heaters is converted to heat. (This does not mean electric heat is environmentally benign. Large-scale hydro dams flood river valleys, displacing wildlife, and the reservoirs behind them produce methane, a greenhouse gas).
For homeowners, the big draw to electric heat is the low initial cost. You can buy a 1,000-watt baseboard heater with enough power to warm a 100- to 125-sq.-ft. room for less than $30. The price increases with sleeker, space-saving designs and enhancements such as circulating fans, but a general guideline is that you need eight to 10 watts per sq. ft. Baseboards are probably the only heating system competent DIYers should consider installing themselves, which could result in further savings.
If you're looking at electric heating, you should also take long-term operating costs into account. Depending on the size and condition of your house and whose pricing figures you use, heating electrically can cost hundreds or even thousands of dollars a year more than running a mid- or high-efficiency natural gas furnace.
That said, electric heat can be a cost-effective supplemental system, such as baseboards or portable heaters used to complement your main system during a big chill, or for enhanced comfort, as is the case with electric heating cables installed beneath bathroom floor tiles.
In hot water
Hydronic heating systems use hot water or steam to provide warmth. In older urban homes, that's usually a boiler with hot-water rads in each room. There's no blowing dry air, but you also don't have ducts to link an air conditioner or humidifier into. Since there are no circulating fans or air filters needed, the heating unit itself is typically smaller than a forced-air furnace, but the space savings can be negated if the boiler is oil-fired, requiring a large oil tank. And while a well-maintained boiler can run for 25 years or more, oil tanks can cause headaches for homeowners. They don't even have to be leaking to be a problem. Insurance companies, leery of the high cost of cleanup in the event of a major spill, are insisting that homeowners replace tanks that are more than 20 years old before they'll provide coverage. Hydronic systems can also be gas-fired, which eliminates most of the problems related to the oil-powered systems.
While the basic equipment for hot-water heating–boiler, heat exchanger and pipes–hasn't radically changed since the days of coal chutes, there have been technological advancements. Fuel pumps and burners have been improved for more efficient burning; automatic dampers close when the boiler shuts down, preventing heat loss up the chimney; and where gravity once did the job, circulating pumps now move the water through the system. These advancements have boosted boiler efficiency levels from around 60 per cent to slightly more than 80 per cent for most models on the market today.
The machinery is changing too. Condensing boilers with a secondary heat exchanger, popular in Europe, are now on the market in Canada. And smaller modern baseboard-style radiators take up less living space than the old cast-iron units.
One form of hydronics that's growing in popularity is in-floor radiant heat systems. With these, a boiler or hot water tank warms the water that runs through pipes laid 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 and bathroom.
There are other options to consider, but they make up very small slices of the home-heating pie. Canadians haven't, for example, entirely abandoned the original heat source, fire, but only about five per cent of homes have a woodstove as their primary supplier of heat. Wood heating requires the most hands-on maintenance–i.e., splitting, stacking and stoking–but it's also a good backup during power blackouts. There are also hybrids such as outdoor wood-fired furnaces that provide heat for hydronic systems, but wood is most popular as a supplement to electric heat.
A heat pump works like an air conditioner in reverse, extracting heat from the air or ground and transferring it indoors, although in most parts of Canada the severe winter temperatures call for an additional system.
And in discussing alternatives, we'd be remiss not to mention solar panel and wind-generator systems that can be tied into heating systems.
The final option comes when choosing how to pay for your new system. Since most of us don't have several thousand spare dollars lying around, utilities typically offer installment payment plans as part of your monthly bill. You should also inquire at your local government and utilities, and visit the Natural Resources Canada Energy Star website for information on energy-efficiency rebate programs.
- Maintaining a humidity level of 35 to 45 per cent inside your home reduces static buildup, moderates shrinking and swelling of wood floors and furniture, and prevents dry skin and scratchy throats. Whole-house humidifiers that are mounted on a furnace can be either passive, where the air passes through a water-filled filter, or active, where a fan forces air through a water-saturated bed. Both styles require occasional cleaning and annual replacement of the evaporator pad.
- Forced-air furnaces come equipped with a one-inch 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 their drafty, elderly neighbours, new energy-efficient (R-2000) homes require a mechanical ventilation system that exchanges stale air for fresh. 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 per cent savings on your heating bill for every degree you lower the heat.
- For maximum heating efficiency, break your home into separate zones. This can be done manually by closing registers or shutting off radiators/baseboard heaters or even the doors to little-used rooms, or by installing multiple thermostats and dampers in the ductwork.
- You've heard it before but it bears repeating: one piece of equipment you should have with any gas, oil or wood-based heating system is a carbon monoxide detector. How many other $50 items can save your life?