2 Stage Furnace Disadvantages: 3 Downsides Of 2-Stage Furnaces

Last updated: October 21, 2021

Are you in the middle of deciding about what furnace you should have for your home and you want to know more about the 2 stage furnace disadvantages? Then you have come to the right place.


A lot has been said and publicized about the benefits of the 2-stage furnace but just little about their downside. It is a known fact that many manufactures will not talk about the downside of their products because they want to sell their products.  

So, in this article, we have put together some of the disadvantages of the 2-stage furnace that that you deserve to know before going for one. 

What Is A 2-Stage Furnace? 

Two stage heating comes with two levels of heat output. High for extremely cold temperatures and low for mild temperatures. It has 3 settings, high, low, off. These types of furnaces are effective at eliminating uneven temperature spots. Contrary, the single stage furnaces have only two settings, off and on (full capacity.) 

Although they may sound superior over the single stage furnaces, they do come with disadvantages. 

Let us look at the summary of the disadvantages of 2-stage Furnace; 

  • High initial cost to purchase and install 
  • Higher cost for repairs and maintenance  
  • Lack of Durability  
  • Is not more energy efficient 

Not let us take a close look at the above downsides.  

2 Stage Furnace Disadvantages 

Higher initial cost to purchase: Although they do not cost much more to install, the first and most notable downside of two stage furnace is the high initial cost involved.

They cost several hundred dollars higher than singe stage furnaces. Single stage furnaces are not as complicated as their counterpart and so they cost lesser. 

Higher cost for repairs and maintenance: Maintenance costs and repair costs of these furnaces are higher than the single stage furnaces.

This is so because spares for two stage furnaces are not so common. So, when we compare the two types, the spares for the single stage furnaces are more common and inexpensive 

So, we can see apart from the high initial cost of buying the two-stage furnace, they are also costly overall when it comes to the cost involved in the maintenance and repairs. In the event of a break down, repairs are not as quick as ones done on the single-stage. 

Not more energy efficient: A two stage furnace is not more efficient than a single stage furnace. In a 2006 study, American Society of Heating Refrigeration and Air-conditioning Engineers (ASHRAE) test procedure indicated no difference in the total site energy consumption between the two stage and the single stage furnaces.

Although the energy consumption of the two are the same, the 2-stage designed with BPM motor significantly reduces the amount of electricity use and so can save you on Bills. 

So, whether you will save money by using a two-stage furnace significantly depends on the type of motor is has.  

study also concluded that that furnaces with BPM motors saved a 40% decrease in the consumption of electricity. 

So, Then What Are The Benefits Of Two-Stage Furnace? 

Despite downsides of the two-stage furnace, we have looked at above, there are some benefits that come with them that include the following; 

  • They can reduce temperature fluctuations in your home 
  • Quieter: two stage furnaces are quieter because they start in the 1st stage when the amount of heat required is lower. so, there is no sudden blast of air.  
  • Better air quality: Unlike the single stage, two-stage furnace runs longer time so more air passed through its filtration system which translates into higher quality air from t than the single stage. 
  • Reduced stops and starts minimizes tear and wear. 

Related article: How to quiet a noisy refrigerator compressor

How does a two-stage furnace work? 

2-stage furnace thermostat

They work on lower setting 70% to 80% of the time. From a user’s point of view, it simply does the work by setting the thermostat. When you turn it on, it will start on a low stage and if the desired temperature is not achieved within minutes then it will jump into the high setting. 

On the high setting. The furnace cools your home much faster by producing more warm air into your home. 

Should I Buy A Two Stage Furnace? 

Its entirely up to you to decide but you can use the following statements for guidance;

  • A two-stage furnace will provide the greatest benefit if you have a larger or multi-story home. Its best for heating large spaces. For smaller spaces or home a single stage furnace is sufficient. If you own a smaller home, then consider using a single-stage furnace. This is because it is likely to heat your home evenly. This is also a good option if you know you do not plan to stay longer in your house. 
  • If you are experiencing uneven temperatures (hot spot and cold spots). Due to its lower stage, it runs a longer time which eliminates the cold and hot spots. But Single stage furnaces will run at full capacity, heat up the air quickly and then shut down before the rest of the room is heated, this creates temperature swings. 
  • You will enjoy the long-term benefits such as saving electricity bills if you plan to stay in that home or residence for several years more. 
  • If you value a quieter furnace fan. These furnaces are quieter than the single stage furnaces. 


We have seen that a 2-stage furnace comes with some disadvantages but you must look at both the advantages and disadvantages before deciding what you will get. I hope this article has been helpful to you.