Which is More Efficient: a Fireplace or a Furnace?

fireplace vs furnace efficiency

As warmth creeps back in during the spring, you may wonder if you should keep your furnace running, or switch to your gas fireplace. Which is more cost-effective to heat your home when temperatures are mild? Sometimes it doesn’t quite seem worth it to turn the furnace on, but your toes are still a bit cold. Read more to know more about fireplace vs furnace efficiency.

Your options partly depend on what kind of fireplace you have. Electric fireplaces don’t generate much heat and certainly won’t be cost-effective. Gas fireplaces, on the other hand, can generate a lot of heat. When it comes to choosing between fireplace vs. furnace, you should consider many factors to determine the best way to heat your home. 


In general, most gas fireplaces are less efficient, for the same amount of heat, than most single-stage and two-stage furnaces. You can compare your models directly by looking at their AFUE or annual fuel utilization efficiency. This is a measurement of how much of the fuel your heating appliance uses. Modern furnaces are typically at 97% or higher. Be sure to compare this efficiency with how many BTUs each device outputs. That’s a measurement of the actual heat. 

In general, you’ll find that furnaces are the most efficient. Gas inserts are the most heat efficient kind of fireplace, and wood fires are not efficient at all. 


If you need to heat your whole home, using a clean furnace is best. But, if you want to practice zone heating, you may be able to save some money. What is zone heating? On a mild spring day, use only your fireplace to warm the main area of your house, while you and your family members are in it. After all, the rest of the home doesn’t have to be heated if you’re not in it. You can turn on the furnace before you go to bed to be sure the rest of the home will be comfortable for the night. 


Some people find that when they use the above method the rest of their home gets too cold. If so, you can keep your furnace on at a very low temperature, and then use your fireplace to make up the difference in the main portion of your home. This way, it’ll be easier to transition to nighttime, but you’ll still be saving money on heating the rest of your home. 

That is unless you are heating your home up with your furnace to a temperature that is comfortable for you. In that case, it’s likely best to switch the fireplace off and let your more efficient furnace do the work. 

With the arrival of Spring comes the arrival of milder weather. Get your home ready with the correct HVAC systems for your needs. The experts at Custom Comfort are here to help.  

Get A Quote

By continuing, you agree to our Privacy Notice and consent to receive marketing emails from Custom Comfort regarding its and its affiliates' products and services.