Written by

Tara Farmer

December 28, 2024

Edited by

Jennifer Carlson

Fact-checked by

Kristen Cramer

The right heating system is crucial for maintaining a comfortable and energy-efficient home. While boilers and furnaces both serve the purpose of heating your home, they do so in different ways. In this article, we'll cover the differences, advantages, and disadvantages of boilers and furnaces to help you make an informed decision.

Difference between a boiler and furnace

The table below provides a quick overview of the key differences between a boiler and a furnace:

Cost

The initial cost of installing a boiler or furnace can vary significantly depending on the system and fuel type, brand, size, efficiency, and the home's existing infrastructure.

• Furnaces typically cost less up front, with prices ranging from $2,000 to $5,400+ for the materials and labor, provided the home has existing ductwork.

• Installing a new boiler costs $3,200 to $9,000 on average. Boilers usually have a higher upfront installation cost than furnaces due to the complexity of the piping network and installation process.

Operation

The primary difference between a boiler and a furnace lies in their operational methods:

• A furnace draws outside air in through a blower, heats the air, and distributes it throughout the house via ductwork. It releases heated air through vents in each room. This type of heat distribution is called forced air.

• A boiler heats water, turning it into hot water or steam. The hot water or steam circulates through pipes to radiators, baseboard heaters, or radiant floor systems, where it warms the rooms.

These fundamental differences impact performance, comfort level, and suitability for different home types.

Fuel source

Both boilers and furnaces can operate on various fuel sources. The availability and cost of fuel in your area can significantly impact your choice.

• Furnaces are powered by natural gas, propane, oil, or electricity.

• Boilers can be powered by oil, electricity, natural gas, or wood pellets.

Size & space requirements

Furnaces require less space, so you can install them in compact areas like closets or attics. However, they need a comprehensive ductwork system throughout the home.

Boilers are often bulkier and require more installation space, but they don't need extensive ductwork. This can be advantageous in homes with limited space or those wanting to avoid extensive renovation.

Energy efficiency

Energy efficiency is measured by the Annual Fuel Utilization Efficiency (AFUE) rating. Higher efficiency means more heat is converted into usable warmth, reducing energy waste and potentially lowering utility bills.

In many cases, boilers win for efficiency. Heating air requires more energy than heating water since some air will escape through the duct system. However, both boilers and furnaces come in high-efficiency models. Modern boilers and furnaces have AFUE ratings between 80% and 100%, depending on the model and fuel type.

Maintenance & lifespan

Regular maintenance is crucial for both systems. Furnaces, while cheaper to install, typically cost more to maintain. While both systems benefit from an annual inspection and tune-up, furnaces have filters that need regular changing and ducts that need periodic cleaning to maintain the home's indoor air quality.

• An annual boiler or furnace inspection costs $70 to $130 on average.

• Most professionals charge $75 to $150 per hour for boiler service or furnace repair.

• Boilers tend to last longer than furnaces since they have fewer moving parts.

Furnace vs. boiler: pros and cons

The right heating system for your home depends on the existing infrastructure, available space, local fuel prices, and your personal preferences. Consider the pros and cons of both systems.

Furnaces

Furnaces balance affordability and practical functionality, offering lower upfront costs, rapid heating capabilities, and easy integration for homes with central AC and existing ductwork. However, they are noisier to run, higher maintenance, and their forced air distribution has the potential to circulate dust and allergens throughout the home.

Here's a full list of benefits and drawbacks to consider when choosing a heating system:

Boilers

Boilers are low maintenance and offer significant benefits, such as energy savings, reduced noise, even heat distribution, and better air quality as they don't circulate dust particles like a forced air system can. Still, boilers cost more up front, require more space, and can't integrate with a central AC system for cooling.

The table below offers a quick snapshot of the advantages and disadvantages of boiler heating systems.

Factors to consider when choosing a heating system

The best heating system for your home depends on various factors, including:

• Climate: In colder climates where people use heating for most of the year, a boiler may be more suitable. For warmer areas, a furnace is often adequate.

• Home size: Furnaces are generally better for smaller homes due to their compact size. Boilers are ideal for larger homes where consistent heating across multiple rooms is desired.

• Budget: Furnaces have lower upfront costs, but boilers may be more cost-effective in the long run due to lower energy consumption.

• Existing infrastructure: Homes with existing ductwork may find furnaces easier to install. Boilers require a network of pipes.

• Health & personal preference: A boiler is a good choice if you prefer radiant heat or wish to reduce the potential allergens in the air. Consider a furnace if you prefer quicker heat and a lower initial cost.

• Fuel availability: Consider the cost and availability of fuels in your area. Natural gas, oil, propane, and electricity are common options for both boilers and furnaces.

FAQs about boilers & furnaces

How do I know if I have a boiler or a furnace?

If your home has radiators or baseboard heaters, you likely have a boiler. Boilers are also often connected to a hot water heater. If your home has vents connected to a centralized duct system, you likely have a furnace.

Which is more energy efficient, a boiler or a furnace?

Boilers are generally more energy efficient than furnaces because heating water requires less energy than heating air. Boilers also retain heat more effectively. Look for high AFUE ratings when considering new models for either system.

What is an AFUE rating, and why is it important?

AFUE (Annual Fuel Utilization Efficiency) measures how efficiently a heating system converts fuel to heat. A higher AFUE percentage means:

• More heat generated from each unit of fuel

• Lower energy bills

• Reduced environmental impact

The Federal Trade Commission requires that new furnaces and boilers display their AFUE rating so consumers can easily compare various models.

Getting estimates for a boiler or furnace

Before hiring a furnace installer or boiler installer near you, be sure to:

• Look for HVAC professionals with certifications from the North American Technician Excellence (NATE) or the American Society of Heating, Refrigeration, and Air-Conditioning Engineers (ASHRAE).

• Read customer reviews on trusted sites like HomeGuide and Google.

• Get at least 3 to 5 quotes from reputable installers.

• Only hire licensed, insured, and bonded HVAC contractors.

• Avoid hiring the company with the lowest estimate, as this often signals low-quality work or lack of experience.

• Ask for copies of estimates, heating-load calculations, equipment orders, permits, warranties, and contracts.

• Confirm the quotes include all materials, labor, equipment costs, and an estimated installation schedule.

• Avoid large payments up front. Set up a payment schedule instead.

Questions to ask boiler and furnace installation contractors

When evaluating potential installers, ask these important questions:

• Which model do you recommend for my home, and why?

• What is the AFUE rating of the proposed system?

• Does this installation qualify for any tax credits, local rebates, or incentives?

• Should I consider switching to a different fuel source?

• How many boilers or furnaces have you installed in this area?

• Will you provide a list of references from past jobs?

• How do you determine the correct system size for my home?

• Does my system need a new hot water storage tank?

• Will I need a new thermostat?

• Does your estimate include removal and disposal of the old unit?

• Are there any additional costs I should expect?

• How long will the installation take?

• Do you handle the permitting process, and is that included in the estimate?

• What's the payment timeline?

• Do you offer financing?

• What exactly does the warranty cover, and how long is it valid?

• What maintenance will it need? Do you offer a maintenance plan?