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About Damien

Damien McCusker, Manager of Arpi's residential service division, has been working in the HVAC industry for 18 years and has hands-on experience in new home installations, furnace and air conditioner replacements, sales and residential service. He spends most of his spare time sharing his passion for soccer with his kids and enjoys watching them at soccer practice and games.

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The Benefits of a Two Pipe System When Installing a Furnace

Damien McCusker

For maximum efficiency and heating performance, as well as long service life, a two pipe system is preferable for the installation of high-efficiency furnaces with AFUE ratings of 90% or more. Standard furnaces draw air for the combustion process into the unit from the interior of the house while utilizing a single pipe to exhaust fumes to the outdoors. A high-efficiency furnace, conversely, offers the option to induct outdoor air into the sealed combustion chamber through one pipe while exhausting combustion fumes through another separate pipe. In the two pipe system, combustion air is not drawn from within the house.

Here are three reasons why configuring a high-efficiency furnace installation with two pipes is usually preferable:

3 Benefits of a Two-Pipe System

  • When indoor air is drawn out of the house and into the furnace for combustion, the pressure differential that is created inside the house means cold outdoor air is sucked into the house through a variety of tiny structural cracks and gaps. This infiltration of colder outdoor air makes the furnace work harder and run longer cycles to maintain the desired temperature. Energy consumption goes up and operating costs rise. Drawing unfiltered outdoor air into the house can also degrade indoor air quality.
  • Pressure differential induced by a single-pipe installation also means that venting other fuel-burning appliances in the house is less efficient. The fireplace chimney draft may be impaired as air is drawn downward through the chimney. Exhaust released by a hot water heater may be drawn backwards into the house through its vent pipe.
  • Certain critical furnace components such as the heat exchanger and burners are made of metals which are susceptible to corrosion from fumes often present in indoor air. In the combustion process, these chemical traces from detergents, cleaners and other aerosol products can corrode these components, reducing durability and service life. Generally speaking, fresh outdoor air drawn in through a dedicated pipe in a two-pipe system doesn’t contain these corrosive fumes so expensive furnace components are not compromised.

For more about the advantages of installing a two pipe system with a high-efficiency furnace, contact the professionals at Arpi's Industries.

Our goal is to help educate our customers in Calgary, Alberta about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, download our free Home Comfort Guide.

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