Even though boilers and furnaces serve the same purpose (heating your home), they work in different ways. Boilers heat water and convert it into steam or hot water before dispersing it through your home, whereas furnaces heat air and use a blower to distribute it through your home's duct system. Aside from this major difference, there are also several other disparities between boilers and furnaces, including price, installation and maintenance.
In this guide, we'll explain how both types of heaters perform in each of these categories and more. We'll also provide a brief summary of the main similarities and differences to help you decide which heating system is better for your needs.
What is a boiler?
Boilers heat up water and turn it into steam or hot water, which is then circulated through pipes and pushed out through radiators around your home. There are several types of radiators in use today, including baseboard radiators, cast iron radiators or radiant floor heating systems (which include a set of pipes beneath the floorboards that emanate heat and warm your floors). Modern boilers generally run on natural gas or oil, but there are some models that use electricity or wood pellets.
What is a furnace?
In contrast, furnaces suck in cold air, warm it up and disperse the hot air through ductwork in your home. From there, the air is released through vents to heat various parts of your house. Most furnaces run on natural gas, propane, oil or electricity. There are several different components in a typical furnace, which include a burner (to burn fuel), heat exchangers (to transfer heat), a blower fan (to distribute heat) and a flue (for exhaust).
Boiler vs. furnace: How do they compare?
Furnaces are the cheaper option, with a new midrange furnace costing between $1,500 and $6,000. Boilers are pricier, running between $3,600 and $8,200 for an average model. Keep in mind that these estimates only cover the appliances themselves -- not installation or fuel costs.
Furnaces are easier to install than boilers. In fact, most furnaces can be installed in just a few hours, whereas some boilers take days to set up. On average, furnace installation costs around $2,000, whereas boiler installations are more expensive due to the additional time required.
Regardless, both types of installations can be complicated. Depending on which type of furnace or boiler you choose, connecting a new model of either may involve dealing with a natural gas line, electric hook-ups or other fuel sources – which is dangerous and should be led by a professional.
As far as maintenance requirements for boilers and furnaces, boilers come out on top. They don't need much ongoing maintenance -- especially when compared to furnaces. Regardless, you should still have your boiler checked once per year by an HVAC professional.
However, if you have a furnace, it's extremely important to keep it well-maintained. You'll need to schedule a furnace cleaning and inspection each year, where an HVAC professional will adjust the burners, clean the combustion chamber, clean the blower and more. Outside of this annual cleaning, you should also be sure to replace your furnace filters every few months or so.
Efficiency and performance
Heating your home with water (such as with a boiler) requires less energy than heating your home with air (as with a furnace) -- meaning that boilers will go through fuel slower than furnaces. In other words, your energy and operating costs may be lower with a boiler than with a furnace.
Boiler and furnace efficiency is measured in annual fuel utilization efficiency (AFUE), an expression of how much energy the heating system generates as compared to how much fuel it consumes.
Today's most efficient boilers and furnaces have AFUE ratings between 90% and 98.5%. In short, the higher the AFUE rating, the less fuel is wasted, which saves you money and is better for the environment.
Furnaces and boilers perform similarly in terms of expected lifespan, but furnaces have a slight edge in this category. When they're well-maintained, furnaces can last between 15 and 30 years. Boilers tend to last up to 20 years. Of course, the lifespan of either one will depend on how often you use it and how well it's maintained.
Outside of these main criteria, there are a few other things to consider when choosing a boiler or a furnace for your home.
For example, if you suffer from allergies, then a furnace may not be the best choice. Furnaces blow hot air through your ductwork, which can spread dust, allergens and pollens around your home. Boilers do not produce air, so they won't create the same type of drafty environment.
Boilers have their own set of disadvantages as well. Since they rely on pipes running throughout your house, there is a risk that the pipes may freeze or burst during winter storms or cold weather.
Finally, if you're sensitive to noise, a boiler will be a better fit because they're quieter than furnaces when in use. With that said, neither type of device should be overly loud or produce grinding, rumbling or popping sounds. If yours does, shut off your heating system and contact your HVAC company.
The bottom line
With all of this in mind, the question remains: Are boilers or furnaces better? The truth is that it depends on your budget and personal preferences. If you're looking for a cheaper heating device (including installation), then a furnace makes the most sense. But if you're interested in a lower-maintenance option, then a boiler could be the right choice.
If you're interested in finding a greener alternative to fuel-burning boilers or furnaces, consider investing in solar energy. Solar panels can be used to power your home at any time of the year (yes, even in winter). They may reduce your monthly energy bills and put less stress on the environment, too. Outside of the home, solar panels can even be used on your RV or camper van to give you an extra power boost on the road.
Read more about home energy
- How to find the right size furnace for your home
- Solar panel buying guide: Everything you need to know
- How many solar panels do you need to power your house?
- 7 easy and free ways to save money on your gas, electric and water bills now