Upgrade To High-Efficiency Heating? Do The Math To Find Out
“Newer” and “better” doesn’t always have to mean “more expensive.”
When it comes to your home’s heating system, a replacement model may cost you money–but your old system might be costing you even more, when you consider differences in energy efficiency.
Obviously, heating fuel prices have been on the rise in recent years; in response, new furnaces and boilers have become considerably more fuel-efficient. The efficiency of furnaces and boilers is usually measured by AFUE (Annual Fuel Utilization Efficiency), which tells you what percent of the fuel is utilized to heat your home over the course of the entire year. An AFUE of 75 percent, for instance, means that 75 percent of the heat makes it into your home’s air, while the other 25 percent is lost. Whereas old systems sometimes had AFUE ratings below 60 percent, a high-efficiency furnace or boiler can exceed 95 percent AFUE.
If you know the AFUE of your existing system, and how much you currently pay for heating bills, you can calculate how much a high-efficiency system would save you.
- First, multiply your annual heating fuel bill by your current AFUE. If your existing system has a 70 percent AFUE, and you are spending $1,000 on fuel, then you are spending $700 on the heat that is actually utilized, and $300 is wasted due to inefficiency.
- Next, divide that answer–the $700–by the AFUE of the high-efficiency system you are considering. If that is 90 percent, then $700 divided by 0.90 is $770. This is how much you would pay with the new system.
- The difference between the two–what you are currently paying, and what you would pay–is how much you would save with the new system. In this example, it would be $230 per year.
Also note that, since the replacement system requires 23 percent less fuel to provide the same amount of heat, it can be 23 percent smaller than your old system. This saves you money on the replacement cost.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).
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