Understanding The Differences Between A Boiler And A Furnace

cat sleeping on a radiator from a boiler heating system

It is a common misconception that furnaces and boilers are the same things as these terms are used interchangeably by many homeowners. However, while a boiler vs. furnace, two very different types of HVAC equipment, do have a fairly similar function, the manner in which they operate couldn’t be more different.

As a discerning homeowner, you will need to choose which of these two devices will serve your home’s needs the best. For this reason, here are some of the considerable differences you should consider when choosing a furnace or boiler system for their specific advantages.

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Differences Between Boiler Heating Systems And Forced- Air Furnaces

To shed some light on what could otherwise be a difficult decision, here are some of the things you have to know about these two heating options.

The boiler is a large enclosed container that contains a special liquid, typically water, that will be heated so the vapor can be used as the primary component for the heating system. The steam or vapor generated by the boiler will distribute the heat throughout the heating system and the home.

The use of water or another liquid for heating up the home is called the radiator system. In addition to the boiler itself, there are some other components of the boiler system. There are also radiator units located at strategic locations throughout the home connected by a piping system and the circulator pump that passes the heat through the system.

What Is A Furnace?

image of a furnace

The furnace is also used to heat the building except that it relies on heated air to keep the home warm. The furnace is used to warm the air that will be passed from room to room. This has also been referred to as the “forced-air heating system” because the cool air in the home is pushed (forced) through the heat exchanger where it will be warmed and returned to the interior through the HVAC duct system.

There are 3 important types of furnaces to know about categorized by their functional orientation. These are horizontal, upflow, and downflow options. The furnace can be fueled by electricity, gas, or oil.

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What Are The Most Important Differences Between A Boiler And A Furnace?

The biggest difference between a boiler and a furnace is the way they operate. The boiler works by “boiling” water that is stored within a thermal tank that will keep it warm and distribute this warmth through the home. The hot water is passed through a system of water pipes that will direct the heated water to the radiators that will keep the home warm. As long as the steam or hot water is flowing, the home will be suitably heated.

A furnace heater is a bit different and requires a heat exchange to function properly. Instead of a fluid that is used to keep the home warm, the cool air from the home is sucked into the furnace, heated, and circulated through the home via a duct system. This circulation is accomplished with the use of a blower motor that keeps the air flowing through the vents.

Boiler Vs. Furnace: Energy-Efficiency

As we remember from high-school physics, it takes more energy to heat a gas than a liquid. Therefore, a furnace will consume considerably more fuel than a boiler system. Then a boiler may be slightly more expensive than a furnace but can be expected to last considerably longer than a furnace as well. But this also depends on the quality and frequency of heater maintenance and services provided to the unit.

Boiler: Pros And Cons

Boiler Pros

  • Efficiency: The boiler will use less fuel to provide more heat. This means your cost of energy will be lower in the long run.
  • Less Noise:  The boiler does not require a blower that will circulate the heat through the home. Therefore, the level of noise is much reduced.
  • Heat Consistency: The heat provided by a boiler is more consistent than heated air.
  • Air Quality: Because a boiler is not pushing heated air around the house, you will not have to be concerned about airborne contaminants.
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Boiler Cons

  • Heat Only: The boiler can keep your home warm in the cold, but when summer comes around you will need the furnace system which can be used to provide cool air circulation as well.
  • Boiler Installation: Boilers take more time, resources, and effort to install.
  • Slow To Adjust Heating Temperature Changes:  You will have to wait a bit before the adjustments made to the temperature of your home are applied.
  • Boiler Leak Hazard: As they age, the boiler will be more susceptible to a variety of potentially destructive errors. Water can begin to leak in unseen places and wreak damage to the interior structures of the home.
  • Difficult Conversion: If you hope to make a change, it will be especially difficult to have a furnace system installed. The necessary ductwork can be an especially big problem.


Furnace: Pros And Cons

Furnace Pros

  • Flexibility: A furnace can be fueled by gas, combustion, oil, or electricity, there are even more advanced options that can be operated on solar power or geothermal energy — but these options are less than common.
  • Fast-Acting:  Furnaces will heat the home quickly because the generation of heat occurs more rapidly.
  • Cost:  Because they are common and there are more units available, the furnace is a cost-effective option for most homeowners.
  • Leaks:  If your furnace or duct system begins to leak, you will suffer decreased efficiency, but it will only be the air that is leaking, not water.
  • Zero Freezing Hazard: In especially cold regions, a boiler may freeze over and the expanding ice can seriously damage the system. Of course, air will not freeze and therefore, this problem can be effectively avoided.
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Furnace Cons

  • Noise: Because they require a blower, the furnace may be a noisier option. This may or may not be a problem for you. Furnace blowers produce a sound when they move air for distribution. Every time a furnace is turned on, it will make a noise.
  • Heat Consistency:  Heated air does not have the same type of consistent warmth that you can expect from a boiler and heated water. This can lead to some rooms feeling much colder than others.
  • Air Quality: If the air filters and duct systems are not regularly cleaned, the problem of poor air quality will be greater.
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In the end, the choice between these two heating options will come down to what works for you in your specific situation. If you are not sure how to make this choice, call up the experts at Townsend Energy. Your heating professional will help you make the best choice for you.

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