How to Measure for a New Fireplace Insert

How to Measure for a New Fireplace Insert

In simple terms, a fireplace insert is a type of enclosed box–generally made of cast iron or steel, but sometimes other materials–with the purpose of holding a fire and trapping in heat. Fireplace inserts are more eco-friendly and energy efficient than a traditional fireplace. This leads to cleaner air, as less smoke is produced, and you get lower energy bills! Definitely a win-win situation. Additionally, not only are they aesthetically pleasing, but they are also a lot simpler to maintain. 

A fireplace insert is not often among the first things people consider when it comes to getting a new fireplace. But deciding to use one can have many different benefits for a fireplace owner. In this blog, we’ll be explaining all about measuring fireplace inserts.  

Tools You’ll Need

Of course, before you buy one, you’ll need to measure it. And to measure it, you’ll need the following tools:

  • Measuring tape – the most important tool!
  • Notepad – or a piece of paper to write down the measurements in.
  • Pen or pencil – to write with.

Luckily, you should have most, if not all, of these tools on hand to get the job done.

How to measure a fireplace insert

The best way to start is by measuring the dimensions of the fireplace insert. You need to measure the length, height, width, and depth of the firebox before you go shopping for your insert. Basically, you need to measure how long, high, wide, and deep the firebox is. You could use any measuring device of your choice–from a simple measuring tape to a more advanced tool such as a laser distance measuring device.

Step 1. Measuring the Length and Height

To ensure your new fireplace insert fits like a glove, take careful measurements. Start with the standard height measurement at both sides of the front and back. Then measure left to right across the opening plus any addons or extra shapes on your insert. To measure the height, simply measure from the floor (or, bottom of the insert) to the top. With all of these specs in hand you’ll be ready to make an informed decision.

Step 2. Measuring the Width

You’ll want to measure the width of the opening and back wall from both the top and the bottom. 

Step 3. Measuring the Depth

At the center of the fireplace box, measure how deep it is by measuring in a line from the opening to the back wall.

Lopi wood fireplace insert

Other things to consider

Fireplace inserts come in all shapes, sizes, and types. They’re not a one-size-fits-all. You can find a variety of wood, gas, and pellet fireplace inserts at Energy Center-Manhattan Pool, giving you plenty of options to find the right inserts to suit your needs. Of course, you would want to make sure that the fireplace insert will fit into your house before you spend your money on it. 

Some factors to consider when planning your fireplace are: what type of mantel will go against the wall, and if you plan to continue making updates to the shelf or mantel. When designing any room within your house, there is always something essential which needs attention before decorating. 

Another thing you should measure or take into consideration is how much heat you want and need for the particular room the fireplace insert will be in. Ideally, you should figure out how much heat or thermal output your room needs, which is generally measured with BTUs. Most inserts will deliver anywhere between 30,000 to 80,000 BTUs. And the bigger the room, the more heat you will need to generate. 

Lastly, you should also take into consideration safety regulations, what fuels are accessible to you, and how much you want to spend on a fireplace insert.


No worries; you can trust the experts to help you measure and install your new fireplace insert. Energy Center-Manhattan Pool is one of the best places you can trust. We’re dedicated to all your hearth needs, and offer a variety of brands for wood, gas, and pellet inserts. Additionally, you could give us a call today or stop by our convenient Manhattan, Kansas location.

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