When choosing a new furnace for your new home, it makes sense to purchase one that's as energy-efficient as possible. Many homeowners start by looking for furnaces that are Energy Star certified. Indeed, this is a good starting point, since the Energy Star label indicates that the Department of Energy agrees that an appliance is energy-efficient. However, there's more to an efficient furnace than an Energy Star label. Here's a look.
The acronym "AFUE" stands for Annual Fuel Utilization Ratio. This is an indication of how much heat the furnace produces for every dollar's worth of fuel it consumes. The lowest AFUE you should settle for is 90, but if you're willing to spend a little more, you can find very efficient furnaces with an AFUE of 95 or 98.
A furnace that's too large for a home will use more energy than necessary, as will one that's too small. Your HVAC technician should recommend an appropriately sized furnace for your home, but if you're doing your own research and looking into various furnace models, it helps to know a little about this yourself.
A good way to estimate the proper furnace size is to multiply the square footage of your home by 25 to 30. So for example, if you have a 1,000 square foot home, you'll need a furnace that provides 25,000–30,000 btu. However, there are a few other factors that come into play here. If you're buying a very efficient furnace, like one with an AFUE of 98, you may be able to get away with a slightly smaller model. On the other hand, in a very cold climate, you may need a slightly larger model to keep up.
The way a furnace is installed has a huge impact on its efficiency. If the ducts are not sealed properly, the gas lines are not run in the right way, or the furnace is placed in the wrong location within the home, it may end up using a lot more energy. This is one reason why it's so important to have a reputable HVAC contractor from a company like Universal Enterprises Inc. install your furnace. Don't rely on a friend who is the king or queen of DIY or attempt to do this yourself after watching a few YouTube videos.
By choosing a furnace with a high AFUE that's properly sized for your home—and then having it installed by an expert—you can enjoy the greatest energy savings.