Choosing The Right Size Wood Insert: A Comprehensive Guide

A wood insert placed inside a wood fireplace improves fuel-burning capacity. It is essential in enhancing a fireplace’s energy efficiency and reducing emissions. Wood inserts are an upgrade on old fireplaces. Installing the right size wood insert enhances a room’s ambience and comfort. 

Selecting the Right Wood Insert

The size of a wood insert is greatly determined by the existing masonry. Inserts are also available for new construction projects where there was no pre-existing fireplace. Wood inserts blend with various decors and styles. 

Inserts are built to fit, which makes it essential to purchase the right size. The successful taking of the dimensions requires a measuring tape. Use a pen or pencil and a notepad to write down the measurements and related notes.

The following are factors to consider when choosing the right size of a wood insert:

  • Measure the opening of the fireplace

When shopping for a wood insert, start by measuring the opening of the existing fireplace. Inserts come in various sizes to fit all kinds of fireplaces, and knowing their dimensions significantly narrows the search for the right wood insert.

Measure the fireplace opening’s depth, width, and height. The measurement should include any existing trim or hearth. Avoid estimating and take concise measurements and record them accurately, as they will be used to determine the size of the wood insert. 

Measure the height from both sides of the back and front of the open fireplace. The height starts from the floor or bottom of the opening.

  • Measure flue size

Use a torch and protect your eyes from soot and debris inside the chimney when measuring it. If the flue is round, measure the diameter. If it has another shape, measure the width and depth of the narrow part above the fireplace. If the flue is odd-shaped, measure the longest parts.

  • Check for any obstructions

Check the fireplace interior for any obstructing parts. Check for the same on the mantel, the trim, and other structures around the fireplace.

  • Take measurements of the firebox’s depth

Measure the distance between the fireplace’s opening and the back wall. 

  • Take pictures of the fireplace

Before visiting a fireplace dealer, take pictures of the fireplace in good lighting and from different angles. The pictures will help the dealer understand the shape and size of the fireplace that requires the wood insert.

Also, please take pictures of the chimney from the outside to confirm its compatibility with the required venting for a wood-burning fireplace insert. 

  • Measure the room

Some authorities require the dimensions of the room where the insert will be installed. The measurements guide the buyer in calculating the fireplace’s efficiency or capacity to warm the room.

  • Consult a dealer or contractor

It is a requirement that a fireplace insert fits into the open fireplace like a glove. Take all the measurements several times for confirmation. There may be discrepancies in the measurements of the fireplace opening. A homeowner also, may lack the skills or materials to measure the dimensions.  

Fortunately, experienced contractors can take the measurements and advise on the best wood insert size and type. Some dealers also offer designed forms that guide buyers on how to take the measurements and record them.

There are standard-size inserts on the market, guided by standard architectural and masonry measurements used in constructing homes and fireplaces. Still, some wood insert suppliers can deliver custom wood inserts upon a customer’s request.


Buying and installing wood inserts requires accuracy and skill. It begins with taking the right measurements of a fireplace to determine the right size of the wood insert. To enjoy the benefits of a bespoke wood insert, consider other features, such as their material and design.

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