Emergency Services Available
Home 5 Blog 5 The Efficiency of Furnaces and Boilers

The Efficiency of Furnaces and Boilers

by | Jan 11, 2022

You probably do not give much thought to your home’s heating system on any given day. But during the bitter Grand Rapids, Michigan winters, your home’s heating can be a daily concern, and a decrease in your boiler or furnace’s efficiency can spell chilly temps and higher utility bills for you. 

Keep reading to learn everything you need to know about the difference between furnaces and boilers and their respective efficiencies.  

What’s the Difference Between a Furnace and a Boiler?

Some homeowners do not know whether they have a boiler or a furnace heating their home due to the fact that the terms are often used interchangeably. Boilers and furnaces ultimately do the same job — they heat your home — but they go about it in very different ways. 


Furnaces heat your home by warming up the air and then circulating it around the house, raising the ambient temperature. These devices are a popular heating option for homeowners because they tend to be less expensive, take less time to set up, and are much less likely to freeze over in the winter. 

However, the heating provided from a furnace is more likely to feel drafty and uneven instead of like a steady temperature throughout the house. 


Radiant heating, which is one of the oldest forms of heating, is rising in popularity again because of its warmth and efficiency. Furthermore, advancements in technology have made radiant heating pipes more affordable and durable. 

They then collect the cooled water and start the process over again while operating very quietly. This method of heating provides a much more even and consistent temperature throughout the house without running into drafts caused by vents. 

The main disadvantage of boilers is that they are more expensive than furnaces. Also, while both heating methods can spring a leak, the water damage caused by a leaking boiler can be quite extensive. 

Combi Boilers

Combi boilers, or combination boilers, are essentially a hot water heater and a boiler in one appliance. Their compact design allows you to save a lot of space by eliminating the need for a second separate appliance. 

Combi boilers also tend to be more efficient than other heating methods, meaning you save more money because you use less energy. 

However, they are not without fault. Combi boilers may not be ideal for very large families or properties because they lack a backup water tank and therefore have trouble meeting very high water demands. Additionally, if your combi boiler stops working for any reason, you are not just missing a heat supply; you’re out of hot water too. 

How are they Powered?

Furnaces and boilers can both be powered by electricity or natural gas, depending on what model you get. 

Some furnaces are even fueled by oil or wood pellets, whereas some boilers can run off of a propane supply. If you know what kind of fuel supply you want to use ahead of time, it can be easier to narrow it down to a few boilers or furnaces that fit your needs. 

Natural gas is currently the cheapest fuel source, but it does add a bit of time to maintenance since the gas line must be inspected and serviced properly. 

How Is Efficiency Measured?

When it comes to measuring the efficiency of furnaces and boilers, it is all about the Annual Fuel Utilization Efficiency, or AFUE. A furnace or boiler’s AFUE can be found on the side of the appliance in the form of a percentage. 

For example, if a boiler has an AFUE of 50%, that means 50% of the energy it uses as fuel is used to heat the house, but the other 50% is lost. An AFUE of anywhere from 56% to 70% is considered to be a low-efficiency boiler or furnace, whereas 90% and higher is considered highly efficient.  

What Impacts Efficiency?

As appliances get older, they naturally become less efficient and eat up more energy. Many older heating systems already started at a lower efficiency rating than today’s options but have become even less efficient as they’ve gotten older. 

It is possible to add on to your current boiler or furnace in such a way to improve its efficiency, but this can be expensive and is not always a long-term solution, so it is not a smart idea if your furnace or burner is at the end of its life and will need to be replaced soon anyway.

Boilers and all-electric furnaces boast the highest AFUE ratings, reaching as high as 98.5% in modern models. This rating can save you a considerable amount of money if you are upgrading from an older heating system.

Proper Maintenance of Boilers

Boilers are relatively easy to maintain, especially when compared to furnace heating systems. However, there are still regular annual maintenance tasks that need to be performed, like:

  • Checking the components and connections for corrosion
  • Checking all surfaces for cracks
  • Flushing the boiler
  • Lubricating the pump
  • Testing the pressure release valve
  • Thoroughly examining the vent
  • Checking the heat exchanger for leaks
  • Sealing any holes or cracks in connections

With all of the minutiae that go into inspecting boilers, most homeowners opt to rely on professionals for the maintenance of boilers. Hiring a professional to keep up with your boiler maintenance and perform annual inspections is the best way to extend its lifetime and prevent costly repairs due to negligence or oversight. 

Proper Maintenance of Furnaces 

Furnaces are a little bit trickier than boilers to maintain. They require annual inspections and filter changes every one to three months. While you can clean and change the filter yourself, the annual inspection for the maintenance of furnaces must be completed by a licensed professional. 

This requirement exists because professionals know exactly what to check and what to look for in order to ensure that all of the parts are working correctly, efficiently and pose no safety hazards. 

What Type of Heating System is Best for My Home? 

There is no clear-cut winner when it comes to boilers versus furnaces. They each have their own set of pros and cons to consider, but the final decision will come down to things like the size of your house, your budget, and your personal preference. 

What works for one family may not be suitable for another. If you need help deciding what type of heating system is best for you, you can always enlist the help of a trusted local pro. They will have a lot more direct product knowledge and can guide you in the right direction based on your living situation. 

Another thing to consider when selecting a heating system is whether anyone in your family has allergies. Furnaces may release dust and other allergens into your home if the filter isn’t cleaned and replaced regularly. 

So if anybody in your family has bad allergies, then a boiler would most likely be the right choice. 

High-Efficiency Furnace Installation in Grand Rapids

Investing in a new high-efficiency furnace can slash your utility bill and decrease your impact on the environment. That’s why many Grand Rapids residents are upgrading and ditching their old money-eating heating systems. It can also add value to your home, so you get back some of what you spent when you go to sell your house. 

Whether you’re ready to make the switch to a high-efficiency furnace or you just need some maintenance and TLC for your current heating system, the pros at Lake Michigan Heating, Cooling, and Plumbing have got you covered. Give us a call today to find out why our customers stay customers for life.