Buying a New Furnace – How to Guide

The Heat is On

Are you considering replacing your furnace? There are several benefits to replacing your old furnace. New furnaces are more reliable, more efficient, and quieter. You will also experience a big boost in your home's comfort. But which furnace is right for you? Great question! Below we’ve listed a few items to consider before you decide on a furnace. 

Gas and propane are the most common heating fuel so this report focuses on gas and propane furnaces.


How do most homeowners go about buying a new furnace? Most will call contractors and ask for estimates. We did too, well sort of. We obtained over 500 estimates from local residential heating and air conditioning contractors and took into account experiences from over 100 clients, this is what we found.

Size Matters
The furnace should meet the needs of your home and the existing air conditioning system. A furnace that’s too small won’t keep your home warm during the coldest days of the year. To avoid that possibility, we found most contractors oversize most furnaces.

The initial installation cost is only one of the many drawbacks of that strategy. A furnace that’s too big will cycle on and off more frequently. That places greater wear on its components, wastes energy, and reduces the life expectancy of the furnace. 

Efficiency Also Matters
Gas and propane are currently the most common heating fuel sources. How efficiently a furnace converts gas into heating energy is reflected in its annual fuel-utilization-efficiency (AFUE) rating, which is measured as a percentage. The higher the AFUE, the more efficient the furnace. One other thing to consider is the environmental impact of your furnace. Higher efficiency furnaces emit fewer emissions, therefore, higher efficiency furnaces are more environmentally friendly.

Like most products, furnaces have become more efficient over the years. A gas furnace manufactured in the ’70s typically has an AFUE of about 60%. The lowest efficiency allowed by the EPA for new gas furnaces today is 80% percent, and some models can achieve over 98% efficiency.

Most and Least Reliable Furnaces
If you have to replace your furnace, you’ll be glad to hear that new gas or propane furnaces can save you up to 40% in heating costs. They are also much more reliable. 

Reliability is especially important because, according to consumer reports, when a furnace fails 77% of the time they need significant work. 

Most homeowners will be surprised to learn that there are about 150 brands of furnaces, but only 6 manufactures in the US. All that to say that nearly all furnaces are the same in terms of reliability. What we found to be the clear differentiating factor is who installs the furnace. Finding a trustworthy HVAC contractor is what matters most. 

It should come as no surprise then that in our survey of repair history, we found no statistically meaningful differences in the percent of models ever repaired for the leading brands of furnaces. 

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