Contents

1. Understanding Furnaces
2. Forced Air Systems
3. What to consider before replacing your furnace?
4. Comparing Furnaces
5. Cost Considerations
6. 3 Major Factors Affecting Cost?

Note: Only professional, licensed contractors should install or service gas-fired appliances!

1. Understanding Furnaces

A gas fired warm air furnace uses natural gas or propane burned in an open or sealed chamber to heat an exchanger, and with the help of a blower or fan, move air across the exchanger into ductwork to heat the space. Its basic components are: a gas valve, burner assembly, heat exchanger, blower, and cabinet.

There are a number of unique combustion chamber and heat exchanger designs for gas furnaces that are copyrighted or patented by different manufactures.

Efficiency of a gas furnace corresponds to the type of burner. Some open burners use a standing pilot or electronic ignition, and draft naturally through the heat exchanger into a hood and smoke pipe, and are usually 80% efficient or less. Other open burners use electronic ignition and a ventor motor to meter the exhaust gases through the heat exchanger and into a chimney, and are 80-90% efficient. Condensing gas furnaces use a sealed chamber, a condensing coil to extract as much heat from the exhaust gases as possible, and a ventor motor to meter the flow through the exchanger, then vent into PVC pipe. This type of furnace has an efficiency rating over 90%.

Accessories that can be installed inside or outside the furnace include:

• Fan Center to turn the blower on independent of the heat cycle
• Air Filter
• Electronic Air Cleaner
• High Performance Media Air Filter (HEPA)
• Humidifier
• Evaporator Coil for central air conditioning

Sometimes a condensate pump will be used to dispose of the water generated in the dehumidification process of the air conditioning, or the condensing of exhaust gases from a high efficiency furnace.

A Zone control panel and motor actuated dampers will be attached to the furnace or ductwork if the system is zoned.

Routine maintenance that homeowners can perform should be limited to:

• Monthly Filter Replacement
• Washing the Electronic Air Cleaner grids
• Cleaning the Humidifier (if so equipped)

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2. Forced-Air Systems

By far, the most common type of central heating system used in Canadian homes is forced air (with a furnace as the heat source). Among its advantages are its ability to provide heat quickly, to filter and humidify household air, and to provide ventilation and central air conditioning.

In addition, with an efficient circulating fan motor, the furnace fan can be used year-round to provide continuous air circulation throughout he house while efficiently balancing the distribution of heat in colder months. It also allows for overnight thermostat set-back, a simple way to save energy.

Forced-air heating systems also have some disadvantages. The temperature of the air coming from the heating registers can vary depending on the type of system. The air can sometimes feel cool (especially with certain heat pumps), even when it is actually warmer than the room temperature. The effect is much the same as the cooling action of a fan or a summer breeze. In addition, there can be short bursts of very hot air, specifically with severely oversized systems. Some people may find such characteristics uncomfortable at times. The ductwork that distributes the heat may also transmit the noise of the furnace and circulating fan to every room and can circulate dust, cooking and other airborne odours throughout he house.

In most cases however, professional, licensed contractors will be able to diagnose and correct these system-related problems.

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3. What to Consider Before Replacing Your Furnace?

There are a number of reasons why you might consider upgrading or replacing your heating system. These include:

High Heating or Maintenance Costs — Many heating systems are unreliable or operate inefficiently because of their age, their use of old technology, or their simply not working the way they should. This wastes fuel and increases your heating costs.

Comfort — How well your house is heated plays a big part in how comfortable it will be. If your furnace is not delivering enough heat to the whole house or to specific rooms, your comfort will suffer throughout the winter months.

Air Quality — As mentioned in the "Air Cleaner" section, if your furnace (or other fuel burning appliances) is not operating properly, combustion gases such as carbon monoxide can accumulate inside your home which could have serious (and potentially lethal) effects to the occupants in high concentrations.

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4. Comparing Furnaces

When comparing brands on our site, make sure you consider the following criteria:

• 90%+ AFUE Rating - Hi Efficiency Furnace (Condensing Heat Exchanger)
• 80%+ AFUE Rating - Mid Efficiency Furnace
• Variable Speed Motor technology - reduces electrical consumption & maximizes efficiency
• Heat Exchanger Warranty
• Parts Warranty
• Quality/Price Ratio being Offered

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5. Cost Considerations

For most homeowners, the major factor in the home heating decision is cost. This factor will have two major components - the capital cost of the installed heating system and the annual operating cost for energy. Other factors, such as maintenance costs, cleanliness and noise of operation, should also be considered.

Installation capital costs of various heating systems, depending on whether they are new or retrofitted, include such items as the following:

• The Brand you select
• Chimney or Venting System (if required)
• Ducting System Modification or Piping
• Thermostats and Controls (in the event of upgrading an existing furnace)
• Labour for installation of any of the above
• Extended Warranty/Service Agreement Costs

Always ask for a firm, detailed quotation before you authorize any work.

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6. 3 Major Factors Affecting Cost

The operating or fuel cost of a heating system is determined by three major factors:

1. Annual heating load or heating requirements of the house

This depends on the climate, the size and style of house, the insulation levels, how air-tight it is, the amount of useful solar energy through windows, the amount of heat given off by lights and appliances, the thermostat setting and other operational factors.

2. Choice of energy source and its unit price

Each energy source is measured and priced differently. Natural gas, being our primary focus, is priced in cents per cubic metre (¢/m 3), dollars per megajoule ($/MJ) or dollars per gigajoule ($/GJ).

3. Equipment Efficiency

The seasonal efficiency with which the appliance converts the energy source to useful heat in the home is also an important factor in the heating cost equation. For example, if a furnace has an AFUE of 80 percent, then 80 percent of the heat value in the fuel is available. The other 20 percent is lost, mostly up the chimney; thus, additional fuel must be consumed to make up for these losses. Improving the efficiency of the heating equipment reduces energy use and cost. The combination of heating load, fuel choice and equipment efficiency determines he annual cost of heating.

When choosing a new heating system, it is important to buy a product that offers the best possible quality/price ratio within the limits of your budget. Take into account the overall cost of each system you are considering; this includes its purchase price, installation cost and operating costs. Often the optimal choice is the most efficient product. A higher initial purchase price is usually more than compensated by lower operating costs and, in some cases, a lower installation cost. The more efficient system saves you money every time you heat your home, and these savings increase as fuel prices increase over the life of he heating system.

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