Now that you have made the decision that it is time to replace your furnace, you will find that technology has vastly improved. First off, since we live in the Oswego, IL. area that will experience most winter days at or below freezing, we should probably only consider furnaces with efficiency rating above 90% AFUE (Annual Fuel Utilization Efficiency). But even in the 90% line of furnaces, we still have some choices to make that will not only impact your fuel costs, but also the comfort you get from your new unit.
- Single Stage: This is most likely the type of gas valve your furnace currently uses, it will open on a call for heat and produces 100% of your furnaces rated capacity until the thermostat is satisfied and at that point completely closes. These furnaces typically have a 92% AFUE rating.
- Two Stage: These units are not only more efficient but can also offer a higher level of comfort. The gas valve in this case has a low fire, so on a call for heat from the thermostat, it will start out on low fire and attempt to meet the demand. If demand is not met over a preset amount of time, the gas valve will open to high fire which is 100% of the furnaces rated capacity. So on milder days, these furnaces can meet demand with only providing a portion of the furnaces output which will not only save on gas, but will also make you feel more comfortable by eliminating large temperature swings. These furnaces are usually rated at 95% AFUE
- Modulation: These are the most efficient and comfortable units available, they have the ability to bring on as little as 30% of your furnaces rated capacity up to 100% and everything in between. With the proper controls, your furnace will match the heat loss of your home and allow the furnace to constantly provide heat without over shooting the set point on the thermostat. That is what makes this furnace the most efficient as well as the most comfortable. They almost always have a variable speed blower so the motor can slow down to not only save energy, but ensure that the air being delivered feels warm to your skin. These furnaces usually have a 97.5% AFUE rating.
At RJ Kuhn, our expert advisors can explain all the different choices available to you so you can make an informed decision as to which equipment will work best for your particular needs.