Today furnaces that are powered by Natural Gas are most popular method of keeping the air warm in Toronto area homes.
The gas furnace is a permanently installed heating and air circulation device – most often located in your basement. Furnaces are also available that use oil, propane, wood and pellets.
How does a Gas Furnace Work
To understand how a gas furnace works, one needs to know the parts of a gas furnace. A furnace is principally divided into three sections. The first section is the made up of the burners, heat exchangers, draft inducers and venting. The second section is made up of controls and safety devices and the third section is made up of the blower and air movement. All the gas furnace parts work together to make the gas furnace work.
Your furnace combines air and fuel (in this case gas) and the mixture is ignited. The resultant flame is then used to heat the air. This air is then circulated throughout the house.
The heating process starts in the burner of the furnace, which is controlled by a thermostat. When the temperature of the house drops down, the thermostat alerts the furnace. The mixture of gas and air slowly starts entering the burner of the furnace and is ignited as a result of an electronic igniter. The air in the burner thus gets drastically heated and starts rising through the heat exchanger which is situated above the burner. It then spreads inside the house warming it up, while the exhaust exits the furnace from a vent and is let outside the house.
In the meantime, fresh air is pulled into the furnace with the help of an electric fan. The air comes in through a large flat grill in your home and passes into an enclosure known as the return air duct. The return air duct passes the air through a protective filter and into the bottom of the furnace. Here the air is pressurized by the fan and forced through the heat exchanger and into the plenum to be delivered to the various rooms in your home. This process is repeated till the temperature of the house reaches a specific level after which the thermostat stops the heating process.
What Else Should I Know
When choosing a furnace there are generally 3 key components you should consider. What is the AFUE rating? What type of heating burners are used? And: What type of fan is used. Once you understand these choices you can make an informed decision when selecting a furnace.
Annual Fuel Utilization Efficiency (AFUE)
The AFUE measures the amount of heat actually delivered to your house compared to the amount of fuel that you must supply to the furnace. Thus, a furnace that has an 95% AFUE rating converts 95% of the fuel that you supply to heat -- the other 5% is lost out of the chimney. Today the Government of Canada requires all furnaces to maintain a minimum efficiency of 90%.
There are three types of heating burners used in furnaces today:
- 1. Single-Stage
- A single-stage furnace uses one set of burners to heat your home as requested by the thermostat.
- 2. Two-Stage
- A two-stage furnace has a primary and secondary set of burners to heat your home. In a two-stage furnace the primary burner has 60% of the furnace’s capacity with the remaining 40% in the secondary burner. When the thermostat calls for heat the furnace can determine how much heat is needed and select the first or second stage.
- 3. Modulating
- A modulating furnace has the ability to customize the heat output to match the actual needs of the home. The goal is to run the furnace for as long as possible using the least amount of energy. This is how you efficiently obtain the most consistent temperature throughout the home. Most Modulating furnaces modulate in 1% increments between 45% and 100% of capacity. There are some models that offer modulation from as little as 15% of capacity.
The final component that you should consider when making a furnace selection is what kind of fan does it use. The multispeed and variable speed fan are most commonly found in furnaces today. However there are some furnaces that use a 5-tap ECM as well.
- 1. Multispeed Fan
- The multispeed fan most commonly comes with 4 speeds total, 2 speeds for heating and two speeds for cooling.
- 2. Variable Speed Fan
- The variable speed fan is also known as an ECM or DC fan. This fan is more energy efficient and provides a much wider range of air speeds. In fact the variable speed fan uses no more electricity than an 80-watt light bulb. Variable speed fan can use up to 24 speed settings ensuring you have the power necessary to deliver air to the farthest corners of your home.
- 3. 5-tap ECM
- A less common option the 5-tap ECM like the variable speed fan is a more energy efficient choice than the multispeed fan. Using no more power than an 80-watt light bulb this fan offers five speed settings for airflow in your home.
Your Encore Home Comfort Advisor will take the time to ensure you find the right equipment for your home. Contact us today for you no obligation appointment.