Boiler vs. Furnace: Is one Better For Your Home?

Unless you live in the balmy tropics of a deep southern state, you probably have some sort of heating system in your home. Heating systems are essential in northern parts of the U.S., whether woodstoves, heat pumps, boilers, or furnaces, as cooler fall/spring temperatures and harsh winters demand supplemental heat.

Key Points:

  • Boiler systems rely on heated objects to raise the temperature of a home, while furnaces directly heat the air.
  • Boilers are more expensive to install and use but offer greater energy efficiency as they don’t lose heat due to drafts.
  • Furnaces have an initial lower cost but require more energy as they create air drafts that can cause quicker heat loss.

Each heating system is different, offering a unique approach to solving the heating problem. This article examines boilers, furnaces, and a few key differences to shed some light on each option.

What Is A Boiler?

Boilers are a type of heating system standard in the United States. A boiler system works by heating water in its tank and sending the steam or liquid throughout the system to heat the home. The steam or liquid moves through a network of radiators installed throughout your home, effectively raising the temperature inside your home.

They’re known as radiant heaters since they don’t directly heat the air inside your home as a furnace does. Instead, they heat objects in your home, raising the house’s temperature. In older homes, boiler systems were equipped with cast-iron radiators or pipes within the baseboards or floorboards, effectively heating the space.

Today, these systems can function as gas or electric heating systems, each with a slightly different setup. With an electric boiler, the system uses heating elements to raise the water temperature in the tank. Conversely, a gas boiler utilizes gas and a flame to raise the water temperature.

Pros And Cons

Like any heating system, a boiler system has its pros and cons. Here are a few perks of these systems:

  • Since the system relies on radiant heating, there’s no concern about heat loss due to a drafty door, as the system heats objects instead of the air.
  • These systems are quiet and efficiently work in the background without disrupting your day.
  • Boilers don’t push air through ductwork in your home, so there’s no need to worry about dust or allergen distribution that would occur as air is forced through ductwork.
  • Boilers can work well for heating floors, as the radiant heating setup works well for even heating.

On the flip side, here are a few drawbacks of these systems:

  • Generally, boilers are pricier than other heating systems, like forced-air systems and furnaces.
  • Boilers rely on water to provide heat, so if the tank or pipe system springs a leak, the resulting mess can be very damaging.
  • The water in boiler system pipes can be susceptible to freezing in frigid climates, raising the risk of burst pipes due to freezing or prolonged power outages.

What Is A Furnace?

Goodman 80,000 BTU 96% Efficiency Upflow, Horizontal Gas Furnace Model GMES960803BN

A furnace is a type of heating system staple that dates back many years. In the early years of use, people used wood and coal to fuel the systems, ensuring their homes remained toasty and cozy throughout the winter months. However, in modern times, wood and coal-fueled furnaces are primarily a thing of the past.

Instead, modern furnaces rely on gas or electricity to produce heat. These furnaces are far more efficient than those of the olden days, as they can use up to 98% of the fuel they consume, making them an energy-efficient option.

Unlike boiler systems, furnaces heat your home by heating the air in it. They convert energy into heat, either by using electricity or gas. This energy generates heat within the furnace’s burner, passing through a heat exchanger, which makes it piping hot. The network of ductwork throughout your home supplies cool air to the furnace, where it is pulled across the heat exchanger.

As the cool air passes over the exchanger, it becomes warmer. Then, it’s pushed back into the ductwork of your home, where it’s distributed throughout, effectively raising your home’s temperature.

Pros And Cons

  • Furnaces tend to be less expensive overall, both for installation and the units themselves.
  • Furnaces usually heat homes much more evenly than some heating systems, like boilers, as they don’t use radiant heat systems.
  • Furnaces usually heat faster than boiler systems, as they heat the air instead of objects throughout the space.

Conversely, here are a few downsides of furnaces:

  • Electric furnaces can be pretty pricey to run, especially in extreme climates. Gas furnaces are usually the better option for these scenarios, as they’re more efficient in harsh environments.
  • Furnaces can be noisy as they kick on, potentially disrupting your day as they cycle.
  • Since furnaces rely on ductwork to distribute warmed air, the system may stir dust and allergens inside the ducts as the air pushes through.

What Is The Difference Between A Furnace And A Boiler?

Although furnaces and boilers share the same ultimate goal of heating your home, the way they achieve this is very different. In addition to the fundamental differences, there are a few additional aspects where one differs from the other, including the following:

Heating Type

The primary difference between a furnace and a boiler is the system itself. While a boiler relies on radiant heat, furnaces employ a forced-air approach. This means a boiler system heats objects in your home, depending on them to radiate heat and warm your home, while a furnace directly heats chilly air in your home to raise the temperature.

Because of this fundamental difference, the setup of each system is starkly different. While boilers feature pipes, radiators, and water tanks, furnaces feature ductwork, fans, and heat exchangers.


Repairing Gas Furnace

Every heating system requires maintenance from time to time, as this ensures the system is functioning correctly. On top of that, regular maintenance helps prolong the system’s life, allowing you to squeeze your money’s worth out of the system before it requires a replacement.

In general, boiler systems usually require less maintenance, as they don’t use forced air to heat the home. Conversely, a furnace often requires more care, requiring routine air filter inspections and replacements every one to three months. This is pretty doable for homeowners, as inspecting and switching the air filter is a straightforward task.

That said, both systems require annual (ideally biannual) maintenance visits to keep them in working condition. So, while furnace homeowners can avoid an extra inspection by handling the air filter switch themselves, furnace and boiler homeowners will need to pay for an annual professional maintenance visit.

Energy Efficiency

While furnaces and boilers are both surprisingly energy efficient, furnaces usually have the edge over boiler systems. On average, a furnace can boast energy efficiency ratings of up to 98.5% AFUE, while a boiler system rarely breaks over 95% AFUE.

This marker stands for the Annual Fuel Utilization Efficiency (AFUE) rating, which you can find on any furnace or boiler. The Federal Trade Commission requires manufacturers to post the AFUE of their new boilers and furnaces, so customers can easily determine the efficiency by reading this tag.

If the tag reads 95% AFUE, the system converts 95% of the energy it uses into heat, while the excess percentage escapes elsewhere, like through the chimney. This percentage falls into the high-efficiency range, as do any other models that feature ratings between 90% and 98.5%. Lower-efficiency models fall between 56% to 70% AFUE, as these models are highly inefficient and have poor conversion rates. These numbers are uncommon in the modern market but are standard for older models.

Monthly Costs

In most cases, installing a furnace system is cheaper than installing a boiler system. Of course, this hinges on whether you have existing ductwork, as installing ductwork in an existing house is a major remodeling job.

Aside from initial installation costs, both systems heat decently and efficiently. Their maximum AFUE ratings are comparable, although furnaces tend to boast higher ratings. Of course, these ratings can fluctuate based on the model in question and factors specific to your home.

For example, if you’re running a gas system, fuel costs might be much pricier in one area than another, making it an expensive option. Electricity costs tend to be fairly standard across the board, but an electric furnace in an extreme climate would perform much poorer than one in a milder to moderate environment.

Because of the variation, making generalized assumptions surrounding the monthly cost factor is tricky.


A furnace is usually the better option if quick and even heating is essential. Since these systems employ a forced-air approach, they tend to heat homes much faster and more evenly than their boiler system counterparts.

Boiler systems utilize radiant heating, and because they heat objects instead of the air, the warming effects usually take a bit longer to take effect. While they can heat a home well, they don’t do it as fast as furnaces or other forced-air systems.

Do Houses Need A Furnace And A Boiler?

Most houses in the United States feature a furnace or a boiler, not both. Since both systems have the same function, adding both to your home is unnecessary. If you’re starting fresh with a new build, you can choose the system that works best for your home based on factors specific to you.

If you’re unsure which option to choose, talk to a local HVAC expert for advice. They can offer insight into the system and which option is more suitable based on your location, so enlisting the help of a professional is a helpful step.

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