It’s getting cold out and it’s time for you to change your heating system. But which will be best, a condensing or a non-condensing boiler? Find out in the upcoming comparison.

Comparison Condensing Boilers Non-Condensing Boilers
Average efficiency95%80%
Initial cost Higher Lower
Running cost Lower Higher
Average life span 15 years 20 years
Maintenance High Low
Emissions Reduced CO2 Higher carbon footprint
Warranty of parts 2-5 year 1 year
Warranty of heat exchanger 10-12 year 20 year

So that’s the difference between condensing and non-condensing boilers in a nutshell. But which is ideal for your home? To find out, take a closer look at these comparisons in more detail below.

The Differences Between Condensing and Non-Condensing Boilers

When it’s damp and cold outside and the evenings begin to draw in, there’s nothing more comforting than coming back to a warm, snug home. But which kind of heating system will make your home the coziest without breaking the bank? Which will last you the longest and give you the least work to maintain?

We’ve compared both types of condensing and non-condensing boilers in different categories below. Consider which of these aspects are the most important for you, and it should make it clear which boiler will suit your home best.

Average Efficiency

The efficiency of your boiler is important as it can help you to save hundreds of dollars a year on your gas bills. Condensing boilers have an average efficiency of around 95%. But, in some cases, these boilers can be up to 99% efficient!

Newer, non-condensing boilers have an average efficiency of around 80%. But the efficiency rate of older models is a lot lower. Some only reach between 55 and 65% efficiency. If you are moving into a house that has an old, non-condensing boiler, it could put a massive strain on your gas bill.

All this makes condensing boilers the most efficient out of the two. This boiler will help you to save more on your gas bill.

condensing boiler on the wall
Condensing boilers are up to 99% efficient, compared to an 80% efficiency with non condensing boilers.

Initial Cost

Considering the initial cost of the boilers is important. Condensing boilers have a higher initial cost than non-condensing boilers. This is because the installation of the average condensing boiler can be between $10,000 and $15,000. But a non-condensing boiler will cost between $8,000 and $12,000.

Of course, these are just averages. The final price for your boiler will depend on quite a few factors. Here are some of them.

  • The size of your home
  • The size of your boiler
  • The amount of work that needs doing to install it
  • Which state you live in

So, which is the ideal boiler for you? If you are making your choice based solely on the initial cost, then a non-condensing boiler will be best.

Running Cost

As we all know, it isn’t usually the initial cost that stings the most. The running costs are what really make a difference in the long-term. So which boiler will allow you to enjoy a warm and toasty home without burning a hole in your pocket?

Condensing boilers are cheaper to run than non-condensing boilers. This is because they are more efficient. Condensing boilers save and recycle more of their heat. All this helps them to put less strain on your gas bill.

Non-condensing boilers on the other hand are more expensive long-term. They are less efficient because they capture more heat from the outside of a room than the inside of a room when preheating cold water. This technique means that roughly 30% of the heat produced is wasted. That is why the boiler has to use more gas and raises your running costs.

Average Life Span

Putting in a new boiler is a lot of hassle. So once yours is in, we want to make sure it’s there for the long haul. So, which boiler has the longest average life span?

Condensing boilers have an average life span of 15 years. Non-condensing boilers, however, have an average life span of 20 years. A non-condensing boiler will last you longer. This makes it the best choice when it comes to the average lifespan.

But these are just averages. Here are some of the things that could alter the boiler’s lifespan.

  • How well you maintain it. You should service it once a year.
  • How well it was installed. The better the initial installation, the longer its shelf-life.
  • How often you use it


You already have 101 jobs to do at home. The last thing you need is to put more on your plate. So which boiler has the easiest maintenance schedule?

Condensing boilers usually require more maintenance than non-condensing boilers. This is because they have a more complex system. Condensing boilers are also susceptible to the following problems.

  1. Freezing. They do not work well in extreme temperatures. This is because the system is built with an external pipe that freezes when the weather gets very cold. So, you might have to call out for help if you get any freak cold weather during the winter.
  2. Condensing boilers can become corroded by acid condensate. This also requires a lot of maintenance in order for the system to continue running well.

Non-condensing boilers, however, do not have these issues. When something goes wrong, they are usually a lot cheaper to fix than condensing boilers. Even so, I recommend that you service your boiler once a year, no matter which you choose.

You should bear in mind that the maintenance of your boiler will also depend on the following.

  • How often you use your boiler
  • How well the boiler was installed

So which is best? Is easy maintenance high on your list of priorities? Then you should choose a non-condensing boiler.

condensing boiler
A condensing boiler will need more maintenance than a non-condensing boiler.


We all want to do our part for a greener tomorrow. And the type of boiler you choose to install can help with that. So which one has a bigger green thumb?

Condensing boilers are greener than non-condensing boilers. They reduce CO2 emissions and have a smaller carbon footprint. This is because they consume less fuel. Condensing boilers also have advanced burner technologies. This technology allows the boiler to burn fewer pollutants such as NOX emissions.

So, if you are choosing your boiler based on how green it is, a condensing boiler will be best.

Warranty of Parts

Boilers are boilers. It doesn’t matter which you choose, something is bound to go wrong somewhere along the line. That is why a good warranty will help you to have peace of mind when choosing yours. 

Both condensing and non-condensing boilers tend to have very good warranties. But, the warranty for a condensing boiler is usually better. A condensing boiler will usually come with a 2 to 5-year warranty on its parts. A non-condensing boiler usually comes with a 1-year warranty on its parts.

professional working on boiler
A non-condensing boiler enjoys a longer warranty on parts coverage

Warranty of Heat Exchanger

Parts coverage is important. But the warranty of the heat exchanger is just as if not more essential. This is because the heat exchanger is expensive and tricky to repair and replace.

So which is best? The warranty of the heat exchanger for a condensing boiler tends to be shorter than that of a non-condensing boiler. A condensing boiler usually comes with a 10 to 12-year warranty. A non-condensing boiler, though, usually comes with a 20-year warranty. That is almost double the protection.


So what can we conclude about condensing and non-condensing boilers?

You should choose a condensing boiler if:

  • You are looking for a heating system that will help you to save more money on your gas bill
  • You want cheaper running costs
  • Low carbon emissions is a priority to you
  • You are keen to have a good warranty for the parts

You should choose a non-condensing boiler if:

  • You want a more economical initial cost
  • You are looking for a boiler with the longest life span
  • Easy maintenance is important to you
  • You are keen to have a good warranty on the heat exchanger

Has this article been helpful to you? If so, then why not check out some of our other articles and free guides. You could even sign up to our email list.

Have a great day!