Furnaces

Types of Furnaces

There are two main types of furnaces: one which runs on combustion, and one which runs on electricity. The difference can be quite easy to discern because one runs on a combustion set up using natural gas or fuel to maintain its operation, while the other runs on electricity.

The Main Parts of a Furnace

The furnace has some important components that make it effective in its function. These components require maintenance and need care to protect its high efficiency. Some of the important components you need to know include:

  • Return Air Ducts
  • Furnace Air Filters (Air Quality Control
  • Blower
  • Thermostat or Controls (Energy Management)
  • Burners
  • Heat Exchanger
  • Exhaust Pipes/Flue
  • Plenum

How a Gas Furnace Works

Although the typical thought of a furnace is of that which has been used in the early parts of our century; truth is, furnaces have evolved into an advanced system and can be used to clean, humidify, condition and warm a building all year around.

This type of HVAC system is often compared with the split system because they can do a thorough job of keeping a space warm during the cold months.

Gas furnaces work by producing heat in the burner through combustion of fossil fuels such as natural gas, lp, or even oil, which passes through the heat exchanger. Air passing through the return ducts is filtered and then directed over the heat exchanger which warms the circulating air. The blowers then blows the warm air into the ductwork, carrying and circulating warmer air throughout a facility.

During the summer months, the furnace fan or blower can be used to circulate air for the air conditioning system into the entire building. Furnaces can also use electronic air cleaners when air is circulated from the room through the air filter. At any point that the system is circulating the air it will be sanitizing the air in a building.

Energy Efficiency and Combustion Set Up

Combustion furnaces can include natural gas and oil systems.

Natural gas is pricey yet it remains a favorite in American households due to its energy efficiency. The old-fashioned natural gas units have a 68-72 percent AFUE rating, while the more modern ones have an AFUE rating of around 90-97 percent.

If you happen to live in more remote areas, the less common oil heater system can be very practical. On the other hand, although the initial cost for installing one is more budget-friendly, the energy costs can be three times more expensive than either natural gas or electric furnaces. It’s also quite high-maintenance. Nonetheless, it has an AFUE rating of 80-90 percent, making it ideal for buildings in colder climates.

A furnace using electric heat virtually has an AFUE rating of 100 percent because all the power is turned to heat energy. On the other hand, this heat efficiency is still subject to possible degradation due to leaks in the system’s ductwork or energy recovery units. Therefore, although you may be living someplace with relatively low electricity rates, your utility bill may still pile up due to such heat loss via leaks. These issues can be resolved with proper service and maintenance. Although electric furnaces are 100% efficient, the cost of fossil fuels may be less expensive. Therefore a 90% AFUE rated gas furnace might cost less to operate year over year.

Understanding Your Furnace’s Annual Fuel Utilization Efficiency (AFUE)

You can easily gauge and measure your unit’s heat efficiency by its AFUE rating, which is basically the ratio of the amount of heat released by your furnace system against its total energy consumption. For instance, if your unit has an AFEU rating of 80, 80 percent of the energy consumed is directly translated to heat and 20 percent of the energy consumed is wasted through heat loss.
Manufacturers are now federally required to indicate the heat efficiency rating of each unit, having each unit undergo the necessary efficiency test before selling it. Make sure to check this important label on your furnace so that you can know and decide whether you need to consider other more practical options. While units with a high AFEU rating can be on the pricey side, you will be able to save more money in the long run. Our technicians can analyze your system to determine if a new unit would be more economical.

Service and Maintenance of a Commercial Furnace

Your buildings heating system always carries a potential hazard when improperly maintained. Thus it is your duty and responsibility to have it checked regularly by reliable HVAC professionals. After all, the health, safety and comfort of your family are on the line. By strictly following protocol as recommended by the experts, your unit’s efficiency can be dramatically increased and its life prolonged.

  • Regular changing of filters. Take this as seriously as you would when changing your car’s oil. Accumulated dirt and debris in your filter will strain your unit to work extra hard and use up more energy than necessary, thereby shortening its life span and increasing your utility bill. Filter replacement is recommended every quarter of the year. But do check monthly especially on cold months requiring high usage. Aside from the filter, the belt and drain should also be checked for the typical damage caused by wear and tear. Have your humidifiers and electronic air cleaners checked regularly as well.
  • Have your furnace inspected and tuned up by a reliable service technician yearly, at the earliest onset of the cold season. It would be wiser to do this before the peak season of heating when HVAC technicians are busier and more difficult to get hold of. Seasoned and experienced technicians should be able to cover all aspects of your furnace maintenance, including inspection for cracked heat exchangers, combustion analysis, air flow balancing and proper chimney flue installation. Following these precautionary measures can and will protect and save occupants from fatal carbon monoxide leaks, which can be caused by leaky heat exchangers.

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