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Choosing the Most Efficient Furnace

The word “furnace” actually represents a wide variety of different heating systems today. Though they all share a basic function (they are all forced air heating systems) the method by which they accomplish that function can be vastly different. For a homeowner looking to install a new home heating system, the sheer number of options that furnaces provide can be overwhelming. Fortunately, we’re here to help. Here’s a look at some of the factors that you should consider when looking for the most efficient furnace to meet your needs.


“AFUE” stands for Annual Fuel Utilization Efficiency, and is one of the primary metrics by which furnace efficiency is judged. As the name suggests, the AFUE number is an approximate measurement of how efficiently the furnace uses its fuel over the course of one year. The number is displayed as a percentage, indicating how much of the fuel the furnace burns is converted into heat and how much is lost as waste. Generally, you’ll want to look for a furnace with an AFUE rating of at least 75-80%. Any less than that, and you’ll be spending an undesirable amount of money on fuel that’s not being converted into heat.


The size of a furnace is actually quite important to how well it performs in a home. A lot of homeowners simply go for the largest furnace that they can physically fit in the space, in the mistaken belief that bigger furnaces are more desirable. In fact, if a furnace is either too large or too small it will break down much more often and have a shorter overall lifespan. You should consult a professional if you are uncertain of what size furnace you should install.

Fuel Type

Always be aware of what kind of fuel best fits your situation. Natural gas is the most popular kind of fuel, but it requires a gas line installed in your home by the city in order to work. Electric furnaces will work anywhere that electricity is available, but they are more expensive to operate than other furnaces. Always do your research, and consult a professional if you aren’t sure which furnace is best for you.

If you need to have a new furnace installed, call Red Rock Mechanical to schedule a service appointment. We provide professional heating services throughout Stowe, VT.

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