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High-Efficiency Furnaces Explained

We live in an age when technology moves with such speed that it seems each new product we purchase is outdated by the time we get used to it. However, in the case of heating and air conditioning systems, the advance of technology will always work in your favor. When it’s time to retire an old furnace, you can feel certain that whatever new unit you’ll pick will have a higher energy efficiency rating.

In fact, you can pick a furnace with a significantly higher efficiency rating than any furnace you’ve ever owned before. Where the average AFUE rating for a furnace was between 60% to 80%, there are special high-efficiency systems that have ratings of up to 97%. That means for every 100 units of natural gas the furnace uses, it generates 97 units of heating power. The savings with such a heating system can be tremendous.

How do furnaces manage this level of efficiency?

Here are some of the technological advances in high-efficiency gas furnaces:

  • A second heat exchanger: The furnaces that are known as condensing furnaces have a second heat exchanger that takes the vapor left over from the combustion gases in the first heat exchanger, then condenses it to release even more heat. This helps the furnace use as much of the available fuel as possible, venting away only a small amount of waste.
  • Variable-speed blower motor: A variable-speed furnace can run its blower motor at different settings so that it does not have to operate at maximum power all the time. The blower will automatically go into higher capacity mode as needed. Otherwise, it will run at a much lower power level that will help keep energy costs down.
  • Two-stage burners: Also known as a multi-stage furnace, these furnaces can modulate the power level of the burners and the amount of heat they give off. The furnace will run at a lower level (about 65% of full capacity) until the temperature drops to the point that more heat is needed. These furnaces not only reduce energy consumption, they’re also quieter than other furnaces and help more evenly distribute heat.

Red Rock Mechanical LLC serves Burlington, VT with superb heating services.

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