Build Your Own Fireplace Blower Grate

A warm, active fire in a fireplace.
  • 3-6 hours
  • Advanced
  • 100-500
What You'll Need
Tape measure
Steel tubing
Table vise
Tube bender
Carbide drill bit
Steel strip
Rivet punch
Steel base
Blower unit

Using a fireplace blower grate is the best way to save some money and also the environment. Simply put, it helps create a more effective transfer of heat from your fireplace to all over your home. There are many popular models of fireplace blower grates available on the market, but you can even build your own with the right tools and materials.

How it Works

Before you start building the blower grate, it is important to understand how it works. A fireplace blower grate consists of an air inlet, pipelines or air tubes, and an air outlet. The inlet draws in cold air from the room. This air then passes through a series of tubes or chambers that pass through your fireplace. The air inside these tubes is heated by fire built atop them and is then expelled through the outlet to heat the room. This method of heating ensures that almost 90% of heat energy from the fireplace is utilized in heating your room. However, it is important that this system be thoroughly tested for leaks before use as improper installation can lead to carbon monoxide (CO) levels in your home rising.

Step 1 – Plan

There are some basic principles that you need to keep in mind when planning your fireplace blower grate. The exhaust tubing should be higher than the inlet tubing because warm air rises higher than cold air. This is a key design feature; so do not forget to incorporate this basic design principle into your fireplace grate heater.

Keep the exhaust fan well away from the rest of the room because it can be noisy. It is also a good idea to look for an exhaust fan that is not too loud.

Step 2 – Take Measurements

Now that you have planned out how your fireplace grate heater is going to be, you need to carefully measure your fireplace to ensure that the pipes will fit in properly. Obviously you will need to measure the height and width as well as the depth.

Keep in mind that your grate should leave a few inches on all sides so that you can move it when the fireplace needs cleaning.

Step 3 – Bend the Tubes

Next, it’s time to create the tube system for the grate. The total length of the steel tubing you’ll want to buy will depend on the area of your fireplace, but you will need enough to create a C-shape in the end. If your fireplace is about 16 inches deep, you’ll want the steel tubing to have about a 14-inch straight piece before the first bend, two inches less than the total depth to leave a space in front of the grate at the bottom. So, you’ll want to set your tubing in a table vise at the 14-inch mark and bend the tubing about 90 degrees.

Next, you’ll be creating the height of the grate. The steel tubing will have to be secured to a base, so this measurement will have to be several inches under the overall height of the fireplace. About four to six inches is usually a safe bet, so move your tube about this much distance from your first bend and secure it in the vise. Now, make another bend about 90 degrees.

Repeat this procedure with all of the tubes for your blower grate. Most grates have about four to six tubes total, spaced evenly apart.

Step 4 – Attach Tubes

The tubes will be attached at the top or at the back with a strip of steel and rivets. Start by drilling a series of 1/4-inch holes at either the top of your bent tubes, about half an inch from the edge, or at the back, between the two 90-degree angles.

You need to make sure your steel strip is fit to the proper size based on the number of tubes your blower grate design has and about how far apart you plan to space them. Each end of the grate should be spaced evenly from the ends of the steel strip, and then the tubes themselves should be placed the same distance apart along the strip.

Once you’ve determined the length you need, go ahead and mark the placement for your tubes on the strip. Drill another series of 1/4-inch holes through the strip, and then attach this to the grate tubes using appropriately sized rivets and a rivet punch.

Now, flip the grate over and secure the tubing in a similar manner to a steel base. Drill your 1/4-inch holes in the tubing, and then mark and drill the appropriately spaced marks on your base as well. Attach these pieces together with another set of steel rivets, and it should be done.

Step 5 – Install Blower Unit

Follow the manufacturer’s instructions for installing the blower unit you’ve purchased to the bottom ends of the blower grate tubing.

Step 6 – Test

Once your fireplace grate heater has been installed, you should test it thoroughly to ensure that there are no leaks. While testing the unit, keep a fire extinguisher handy. It is also a good idea to use an accurate CO detector to check for leaks. In fact, with any fireplace grate heater, you should keep some CO monitoring equipment handy to ensure that the CO levels in the room are not increasing beyond the maximum limit.