By Chris Buchanan • September 3, 2018

What is a Boiler?

The boiler: it's one of those elements in the home that we've all heard about but virtually nobody fully understands.

Where is it? What does it do?

If you've ever asked these questions, you're not alone. Luckily, we've got answers.

Here's what you need to know.

Fast Facts About Boilers

The boiler is an enclosed implement that heats water via combustion. Once the boiler has heated water, that heat can be transferred to a process.

The boiler is a popular addition to homes since water is such a simple and inexpensive option for transferring heat throughout a home's processes. While boilers come in different shapes and sizes, each includes a few common elements.

These include the heating surface, which is part of all boilers. In a boiler, hot gas created by combustion lives on one side of the tool while water is on the other. Any part of the boiler that plays a part in creating steam is considered a heating surface. Heating surfaces in boilers are measured in square meters. Boilers with more ample heating surfaces are generally more efficient.

The Parts of a Boiler

Beyond the heating surfaces, boilers are made up of the following elements:

  • The steam system
  • The fuel system
  • The feed water system

Here's a breakdown of each:

The Steam System

The steam system is in charge of collecting and controlling the steam the boiler produces. The machine pushes steam through a system of pipes that direct it to its eventual point of use.

This system of pipes also regulates pressure with valves and pressure gauges to keep the system safe. This is essential since water, when boiled into steam, increases in volume by about 1,600x, and is nearly as explosive as gunpowder. This steam system helps keep the boiler safe for household use.

The Fuel System

The fuel system is comprised of all equipment that is used to fuel the boiler so it can generate heat. While each boiler has a fuel system, the equipment used in the fuel system depends on the kind of boiler and the type of fuel it uses.

The Feed Water System

The feed water system does exactly what it sounds like - feeds water through the system and regulates that water automatically.

This serves an important purpose and ultimately regulates the system to ensure it is meeting the household's demand for steam.

Water supplied to the boiler (which is later converted to steam) is called feed water. This water comes from condensate or raw water.

Are Boilers and Water Heaters the Same Thing?

If you look at it on the face, it seems like water heaters and boilers serve the same purpose. Both generate warm water, so what sets them apart?

The answer is simple: many things.

Here's a breakdown.

What Water Heaters do

Water heaters do exactly what their names advertise: they heat water. Once this water is hot, you can use it to shower, wash your hands, clean, cook, or virtually anything else you need to use hot water for in your home.

Water heaters take cold water from supply pipes in your home and warm it up. Once the water is warm, the heater pumps it throughout your home so it's available from a tap. Water heaters warm potable water and are present in most homes today.

What Boilers do

As previously mentioned, a boiler uses water to create heat, but it doesn't necessarily create hot water that you can pull from the tap in your home. Instead, it turns water into steam and uses that heat to heat the home. The water utilized by a boiler system isn't always potable but can be used to heat pipes within a home's walls, or in a radiant heat system.

What to Know About Boilers

Now that you know the difference between boilers and water heaters, here are a few additional things to know about the wonderful world of boilers:

  • Boilers don't boil water. The term "boiler" is a holdout from the past when steam boilers were common throughout homes. Today's boilers don't boil water as much as they do use natural gas to heat water to about 145-190 degrees.
  • Boilers provide radiant heat. This heat warms a room in a different way than, say, a forced air furnace, which provides quick, mildly-absorbed heat. Boilers are a popular heating option because the radiant heat allows objects to absorb warmth slowly, making a room feel warmer than other heating options. 
  • Boilers do not remove or add humidity. Contrary to popular belief, boilers don't add or remove humidity, unless you're dealing with an older, cast iron boiler. High-efficiency boilers, on the other hand, pull air from outside and use it to create combustion. Boilers are also efficient, which means they don't waste water because they're a sealed system. 

Boilers: an Important Home Implement

Boilers play an important role in heating a home, and are still a popular method for creating reliable, radiant heat. Efficient, sealed, and safe, boilers remain a critical part of many new and historic homes throughout the country.