
You’ve no doubt heard of high-efficiency furnaces, but what makes a high-efficiency furnace better and what can you expect to gain from installing one? First of all, a high-efficiency furnace uses fuel more efficiently. The measurement for efficiency is called an Annual Fuel Utilization Efficiency (AFUE) rating. The Department of Energy calls any unit with an AFUE of 90% or higher, high-efficiency furnaces. AFUEs of 80%-83% are considered mid-efficiency.
Most natural gas furnaces in the 1970s and 1980s were about 60 percent efficient—they only converted 60 percent of the energy in the natural gas into usable heat. Today’s models are obviously much more efficient. Here are some of the improvements that make these new furnaces so much more effective:
· One of the main improvements manufacturers have made is in the combustion of fuel (how the air mixes with the fuel). High-efficiency models feature “sealed combustion” which mixes the air with the fuel at a controlled rate in order to maximize the heat from the fuel.
· The higher-efficiency models are “condensing gas furnaces.” Exhaust gases are run through a second heat exchanger to remove and use all available heat that would otherwise be exhausted. These models pull out nearly all of the heat, sending cool exhaust out and leaving behind condensed water that is drained off.
· Gas valves have been improved as well. A two-stage gas valve heats the furnace quickly, but then drops down to a more energy conserving flow.
· Variable speed motors also save on electricity. Instead of the furnace going on and blasting the home with hot air for a short time and then turning off, variable speed motors run the blower for longer periods at lower speeds. Not only does it use less energy, it‘s quieter and your home stays more comfortable.
· Another improvement is the electronic spark ignition. Instead of a pilot light that is constantly on, the electronic spark ignition fires the furnace on demand.
· The top-of-the-line models are the most efficient and can interact with a thermostat and adjust furnace output and blower speed accordingly. Some models are up to 98.2% efficient.
You will see a significant reduction in your energy bills with a high-efficiency furnace. The exact amount will vary depending on the furnace you choose and the efficiency of your home. In general, you can expect to get your investment back in energy savings in 5-10 years. Call Getzschman and we can help you figure out which system makes the most sense for your home.