Choose the Right Condensing Gas Furnace
All of this information is from NRCan.
Condensing gas furnaces are the most energy-efficient furnaces available on the market today. They are an ideal choice as a new or replacement furnace for virtually any home serviced by natural
gas. Here is why:
- Condensing gas furnaces have an annual fuel utilization efficiency (AFUE) of between 90 and 97 percent, compared with AFUEsof about 60 percent for old furnaces and of 78 to 84 percent for standard efficiency units. (AFUEis the yardstick for rating furnace efficiency.)
- Because of their increased efficiency, condensing gas furnaces use 33 to 38 percent less energy than old models and 10 percent less energy than a standard efficiency model. This helps conserve Canada's natural resources and reduces harmful environmental emissions that contribute to climate change, urban smog and other air pollution problems.
- Any extra cost associated with purchasing a high-efficiency condensing gas furnace will be quickly recovered through energy-cost savings. For example, a homeowner with annual gas costs of $800 for space heating with an old gas furnace could save $300 a year by switching to a condensing gas furnace with an AFUEof 96 percent.
- Some high-efficiency furnaces deliver even greater energy savings by using a variable-speed, direct-drive electronically commutating motor to run the air circulation fan. In homes where the fan is run continuously or for extended periods, such a motor can significantly reduce electricity consumption while providing better heat distribution.
- Condensing gas furnaces are available in a range of sizes and can be installed in the same location as an existing furnace that is being replaced, by the same technicians, using the same ductwork.
How can you tell the level of efficiency of a gas furnace?
Look for the EnerGuide label
To determine the efficiency level of a gas furnace, check its EnerGuide rating on the back page of the manufacturer's brochure – the higher the rating, the more efficient the model. Check where the EnerGuide rating is situated on the scale to see if the furnace you are buying is in the high-efficiency zone.
Even better, just look for the ENERGY STAR ®
The symbol can be found on the furnace, on the packaging or in promotional or educational literature.
Only the top energy performers are eligible to use the ENERGY STAR symbol – residential gas furnaces must have an AFUE rating of 90 or higher to qualify. You may see the ENERGY STAR symbol displayed in various ways.
The international symbol for energy efficiency
The savings in a new high-efficiency condensing gas furnace may be the best investment you can make. The technology for high-efficiency furnaces has been available for many years and is well proven. In 2001, one out of every two gas furnaces sold in Canada (over 100,000) were high-efficiency condensing gas furnaces. They are fast becoming standard equipment in new homes. Upgrading from an old furnace to a high-efficiency gas furnace not only increases the resale value of an existing home, but can also reduce the greenhouse gas emissions caused by the use of fossil fuels. The Government of Canada has issued a challenge to all Canadians to reduce greenhouse gas
emissions. Choosing an energy-efficient condensing gas furnace is one way to meet that challenge.
Facts at a glance
Ensure the AFUE is between 90 and 97 percent
Look for the ENERGY STAR symbol
Use an ENERGY STAR qualified programmable thermostat
Determine the right size of furnace for your home
High-efficiency condensing gas furnace
How the technology works
In a furnace, combustion gases generated by the burner pass across a heat
exchanger and release heat before being exhausted to the outdoors through a chimney. High-efficiency furnaces use additional heat exchange surfaces made of corrosion-resistant materials to cool and condense the combustion gases (causing them to liquefy), thus releasing more heat for the home. The small amount of waste water produced by this process is piped to a floor drain.
This condensing process has another important benefit – it reduces the temperature of the flue gases to the point where they can be vented through a PVC or ABS plastic pipe out a side wall of the house. This eliminates the need for a chimney, which is a major source of heat loss in homes with old furnaces.
Talk to a professional
Before making a purchase decision, ask a certified heating contractor to determine the right size of furnace for your home, taking into account recent technology developments, the heat loss and heat gain characteristics of your house, and other factors. An EnerGuide for Houses evaluation can help you identify possible measures to improve the overall energy performance of your home before you finally decide on the size of the unit.
Need more information?
For information about the energy, economic and environmental benefits of condensing gas furnaces, consult Natural Resources Canada's Office of Energy Efficiency's publication, Heating with Gas. You can view it on-line at oee.nrcan.gc.ca/publications/infosource or order your free copy by calling
1 800 387-2000 (995-2943 in the National Capital Region area) or by writing to
Office of Energy Efficiency
Natural Resources Canada
Ottawa ON K1A 1L3
Source: Natural Resources Canada (NRCan) - Office of Energy Efficiency