Furnace vs Boiler debate
This isn’t often a debate about which system to install. Most homes already have either a furnace or a boiler. You’re likely here to compare the pros and cons of a furnace vs boiler (2025).
For example, in older semi-detached or detached homes, you may come across an old radiator heating system and wonder what it is. In contrast, most modern homes use a natural gas furnace—simply adjust your Nest thermostat and the heat kicks in.
In many homes built before 1960, ductwork was not common. Without forced air systems, a boiler with radiators was the standard.
Homeowners today remain divided: some are loyal to boilers, others to furnaces. Both systems have unique benefits and limitations.
What’s the Difference Between Boiler Radiators and Furnaces?
Both systems keep your home warm in winter, but the key difference in a boiler vs furnace (2025) is how they generate and distribute heat. A boiler uses water, while a furnace uses hot air.
Boilers such as Viessmann, distribute heat from hot water or steam through pipes to baseboards and radiators. The most common models run on natural gas, hot water, or steam, though older homes may still have oil or even coal versions.
A furnace runs on gas, propane, or electricity. Using your home’s ductwork system, it pushes hot air through vents to heat your home. That same ductwork also supports central air conditioning, making furnaces common in modern builds.
Boiler vs. Furnace: Which Is Better?
To break down the boiler versus furnace debate, we’ve created a few categories for you which will help you decide which system is right for you.
Size/Appearance of a furnace vs boiler
Both boilers and furnaces are likely in the basement. Water boilers are typically quite tall and cylindrical. Regulations require them to be installed along the wall of your home, which is why most are in the basement or garage.
Furnaces, on the other hand, are smaller and rectangular. Their smaller size allows more flexibility on location. Most often they are found in the middle of the basement near ductwork, but they could also be up high towards the ceiling if needed.
Keep in mind that you should always install furnaces with at least a foot of space around every edge to keep them from overheating.
Cost of a furnace vs boiler
Whether you install a water boiler or air heating system, buying a heating system for your home isn’t cheap.
- Boiler systems are very expensive, sometimes in the range of $25,000 installed but a good system will last 40- 50 years.
- Furnace prices are typically in the range of $5000-$7000 installed and last about 25 years if maintained properly.
- If you’re installing a furnace, many people choose to add a central air conditioning unit at the same time. Companies will offer discounts to do both at the same time since the technician is there anyways. Central air conditioning units cost roughly $4000 installed.
Why Hire Professionals for Furnace & Boiler InstallationInstallation
We’d suggest you call in the pros on this one. When you start dealing with gas and water, it can quickly get out of hand. Not to mention that your insurance company probably wouldn’t be pleased to hear about a DIY job. Depending on its power source, you could also be dealing with electrical lines.
Beth and Ryan personally use and recommend AIDO Climate Solutions. Call them and tell you we sent you!
Energy Efficiency
Boilers cost more than furnaces, although each heating system will cost about the same to run throughout the winter. In some cases, a boiler that runs on steam may cost more than one that runs on gas or boiling water.
Gas systems are relatively cheap to run. The average Guelph utilities average $75 per month to run a gas furnace and AC system in Guelph.
Maintenance
When it comes to home maintenance and potential repair costs, a boiler is definitely the superior choice. Boilers require very little maintenance after initial installation.
Furnaces on the other hand can break down at the least convenient times. Often times you can replace parts to keep the unit going but inevitably the unit is going to go. We’d also recommend annual furnace maintenance to stretch the life out.
Which Is Best for the Guelph winter climate?
Boilers offer steady heat distribution throughout the home. Some find the circulation of hot air to uneven or even uncomfortable.
Furnaces on the other hand could offer more even distribution of hot air on main levels. The higher the house goes, the further the air has to travel.
If you have a 2 storey, 2.5 storey or even 3 storey home, you may notice less even heat distribution.
Do you have young children?
If you’re moving to an older home that has the upright, century old radiators, you should consider that these can get very hot. These could burn a young child if left unattended. It may be worth calling in a professional to give you more modern options.
Furnace heating systems are generally quieter than boilers, so if an older home has appropriate ductwork installed it might be better to choose air over water.
Which Is Best for Smaller Homes?
Furnaces are better than water boilers for small homes. They take up less space and can be placed in utility closets, which frees up potential living space you might lose with a water boiler.
So, if you live in a townhouse or condo, you’ll likely always want a furnace.
Furnace vs boiler for cooling
If you are considering a house with a boiler system, a major factor to consider is air conditioning. A home with a boiler doesn’t have ductwork and therefore is not compatable with central air. This may be a deal breaker for some.
There are options though if you’re considering a home with a boiler system. The main option is a ductless model. These are wall mounted on the interior, typically above doorways. From the outside, the unit has refrigeration lines that come into the house at specific locations and provide cool air.
The other option are the more common window units which you’ve likely seen. These units fit into an open window and provide cooler air- the main downside here is that you lose the use of this window itself.
Conclusion:
When it comes to the furnace vs boiler debate in 2025, there isn’t a one-size-fits-all answer. Furnaces remain the go-to in modern homes thanks to their lower installation cost, compatibility with central air, and compact size. Boilers, however, offer long lifespans, low maintenance and consistent heat distribution, especially in older homes without ductwork.
If you’re buying or maintaining a home in Guelph or the GTA, understanding the pros and cons of furnaces vs boilers can save you money and headaches down the line. Always consult a licensed HVAC professional before making upgrades, and consider your home’s age, size and future cooling needs.
Whether you stick with a boiler system or upgrade to a furnace with central air, the right heating system will keep your home comfortable for decades.
This post is part of a larger series that Beth and Ryan have created titled “16 Things to Consider When Buying an Older Home“.