Your neighbors come over for dinner one blustery evening and as you welcome them in and take their coats, they can’t help but comment on how toasty your home is. “It’s so warm in here…your heating bill must be sky-high!”

You smile proudly and say, “Not at all – we have a high-efficiency furnace.”

Ok, this might not be your typical dinner party conversation, but with heating costs on the rise, it’s not that far-fetched.

If it’s time to replace your old, barely-hanging-on furnace, you’ll want to pay attention to the efficiency ratings of any new models you consider. Read on as we explain what a furnace efficiency rating is, why it’s important, and what other factors you should consider when determining how efficient a furnace you should buy.

What Is a Furnace Energy Efficiency Rating?

Furnace efficiency is defined as the annual heat output of a furnace divided by the annual energy it consumes. This ratio is called the Average Fuel Utilization Efficiency (AFUE). Because all furnaces that generate heat with a flame produce carbon monoxide, they need to be vented which inevitably allows some heat to escape. The National Appliance Energy Conservation Act of 1987 established minimum efficiency standards for many common household appliances, furnaces included. It required all new furnaces be at least 78 percent efficient, meaning 78 percent of the heat stays inside the home. Before then, a large portion of a furnace’s heat escaped outside through the vent. Today’s standard furnaces are 80 percent efficient, while those with a rating of 90 percent or more are considered high-efficiency.

Understanding Furnace Energy Efficiency

It’s important to note that AFUE primarily tracks heat lost via intentional venting and does not factor in heat loss through gaps in the duct system, inadequate insulation, and other air leaks. So, if you have a super-efficient furnace but leaky ductwork and drafty windows and doors, your heating bill will likely be high.

It’s also important to understand that efficiency isn’t the only factor that determines overall operating cost. A low-efficiency furnace equipped with two-stage heating or a variable speed blower may consume less energy overall than a high-efficiency unit that runs at full power.

Cost Considerations

High efficiency furnaces cost more upfront but save on energy consumption in the long run. So the question is, do the energy savings justify the higher initial purchase price for your home? That depends on several factors, including how your home is designed and insulated, how often you use your furnace, and whether you plan to sell your home in the near future.

The cost of furnace installation will depend on the size and layout of your home, the make, model and features of the furnace, and whether new venting is required to accommodate the sealed combustion system of a high-efficiency system. As stated previously, a drafty, poorly insulated home will likely not reap the benefits of a high-efficiency furnace. While determining a furnace’s efficiency is an important first step, it’s only part of evaluating your home’s overall energy consumption.

If your heating system has finally given up or you’ve decided to replace it before it does, contact C&D Cooling & Heating today for a thorough analysis of your home comfort needs and a new system proposal.