What is a Fireplace Heat Exchanger?

Most of the heat that a fire generates within your fireplace is lost up the chimney. Not only does this prove to be issue when it comes to the comfort level in your home, but it also creates a dilemma as far as heating costs are concerned. Many homeowners have found a simple and affordable solution to this problem. Adding a heat exchanger to your fireplace can lower your monthly heating bill significantly, while keeping your home and loved ones cozy and happy!

Heat exchangers are an efficient way to deliver greater warmth to your home. They are designed to draw in cool air from the home, heat it up, and then disperse this warmed air into your living space. There are many different styles available that can help maximize your masonry fireplace. Some models are easily mounted to the top of the fireplace opening. Others, known as grate heaters, are designed to fit within your firebox. Then of course, there are decorative, welded steel fireplace doors that are designed with a blower to circulate warm air into the room.

Choosing the Right Grate Heater for Your Fireplace

Not every fireplace grate heater is the same, and choosing the correct one ensures the best performance. Here are a few factors to consider before buying:

• Fireplace size: Always measure your firebox dimensions carefully to select a model that fits securely.

• With or without doors: Some heaters are more effective when paired with fireplace glass doors, while others are designed for open masonry units.

• Heat output: Consider how much heat you need—smaller models may work well in compact spaces, while larger homes may require units with higher BTU capacity.

• Ease of installation: Many grate heaters are simple to set up, but double-check whether your model requires professional installation.

• Budget and features: Options range from basic tube designs to advanced models with variable speed blowers and ultra-quiet fans.

Standard Grate Heater

These slide-in heat exchangers feature heavy duty steel construction, UL approved electrical components (these units do need to be plugged in to a power source), variable speed blowers, and the ability to work with or without an existing glass door. The front rail harbors the motor and is situated in front of the grate where you'll stack your logs. The fan pulls in cool air, heats it up, then blows it back into the room. Many of these heaters produce an impressive 40,000 BTUs of heat per hour! The variable speed blower turns on at 110°F and off at 90°F. Not only is this a great safety feature, but it also cuts down on energy consumption.

Tubular Grate Heaters - 4 Tube Spitfire  |  6 Tube Spitfire

A fireplace tube heat exchanger consists of a series of curved steel pipes. The most common styles are designed in a “C” shape. The tubes sit at the bottom of the firebox the curve behind the fire and exit at the top of the fireplace opening. The blower fan (located at the bottom of the tubular construction) draws in cool air, heat its, then blows heated air out into your home. While these heaters certainly do a good job of keeping your home cozy and warm, it is very important that you make sure the steel tubes are made from high-quality steel. They must be approved to withstand the extreme temperatures and corrosive effects of a fire. With these heaters is the tendency for heated air to be drawn back into the fire. Glass doors help prevent this warmth from being drawn back into the fire, allowing the grate heater to emanate more warmth into your home. However, this heater is often found in fireplaces that do not have doors.

Airculators - 39 Inch Long  |  45 Inch Long  |  51 Inch Long

A different take on the grate heater, this sleek design is capable of producing more heat for your home with less power! Installation couldn't be easier: attach the motor box to your hearth area with a screw and then plug the unit in. The attached grate is made from heavy duty steel, while the dual air jets are super quiet. Cool air is drawn in through the fan box and warmed within the heating chamber before being delivered back into the room. This is perhaps the quickest working heat exchanger available today. In addition, it promotes fuel efficiency by cutting back on the amount of wood needed to maintain a comfortable temperature in your home! It is most effective when used with fireplaces that have glass doors, although it can be used in masonry units that do not have doors.

Fireplace Insert Heat Exchangers

Fireplace inserts and doors with an integrated heater are another way to incorporate a heat exchanger into your application. An insert is a metal box that fits into an existing masonry fireplace. Inserts have built-in heating chambers that produce warm air from the cool temperatures that enter the firebox. This option is certainly effective, but not quite as affordable as a mounted heat exchanger or a grate heater. Over the years these have been phased out and wood burning fireplace inserts have taken their place.

For homeowners seeking even more heat output, wood burning fireplace inserts are another option. These units are installed directly into an existing masonry fireplace and operate much like a high-efficiency wood stove. They’re designed to produce a large amount of heat and can often keep an entire floor of a home warm.

Installing A Grate Heater In A Masonry Fireplace

Fireplace grate heaters (or heat exchangers) are compatible with most masonry fireplaces, and do not present much difficulty as far as installation goes. However, it is extremely important that determine the exact measurements of your firebox before obtaining the heater, and that you follow the product instructions for setup and operation to avoid damage or injury.

A heat exchanger or grate heater is a terrific way to efficiently use the heat generated from your fireplace. Cool air is drawn in from the room, heated by the wood-burning fire, then delivered back into the room as comfortable warmth. While each grate heater is different and will require you to follow the specific manufacturer's guidelines, we can give you some helpful hints on how to install the more standard device. Please keep in mind that these directions do not apply to all grate heaters/heat exchangers! They are just general directions.

1. Measure your firebox. Having the correct dimensions will ensure that you are getting a product that will fit perfectly into your masonry fireplace.
2. Insert the grate heater. Whether or not your fireplace has glass doors, a grille or riser bar (the component that houses the vents for air exchange) will be needed. If you have fireplace glass doors, they will sit on top of the riser bar the height of your firebox opening will be reduced by as much as 1 3/8 inches.
3. Install extender bars. These components are included with the grate heater. They can be cut to the width of your door if you choose; this provides a "finished" look.
4. Adjust the heater and extender bars. Make sure the grate heater is centered in the fireplace opening. (If you have glass doors, make sure they are centered as well.) Adjust the extender bars, confirming that the riser bar is the same width as the firebox.
5. Position the cord shield. This barrier protects the power cord from overheating. It should be firmly attached to the extender through which the cord exists. Make any and all necessary cuts to ensure it is the right size.
6. Plug it in and enjoy! Plug the power cord into the nearest outlet. Be sure that it cord is plugged in at all times while the fire is burning. This will allow the fan to run and will avoid damage to the motor.
7. TO CLEAN THE ASH IN YOUR MASONRY FIREBOX: An ash vacuum can be used to clean the ash out of your firebox, as well as any debris inside or around your grate heater. Many ash vacuums come with various hose attachments that are slender enough to fit in and around the grate heater. Always follow the manufacturer's directions for specific guidelines on the optimal care of your heat exchanger/grate heater.

Upgrade Your Fireplace Today

If you’re looking for a simple, affordable way to get more warmth from your masonry fireplace, a grate heater is an excellent solution. For homeowners ready to invest in a permanent, high-output unit, a wood burning insert may be worth considering. Either way, upgrading your fireplace means more comfort, lower bills, and a cozier home.

Frequently Asked Questions

Q: Can a grate heater be used in a prefab fireplace?

A: Yes, but you have to choose models that are specifically made for zero clearance fireplaces.

Q: Do grate heaters save money?

A: Yes. Because they push heated air back into your living space, you’ll need less wood and can often lower your furnace usage.

Q: How loud are the blowers?

A: Most modern models are designed to operate quietly, with variable speed settings for comfort.

Q: Are grate heaters safe to run overnight?

A: Yes, as long as the blower is plugged in and functioning correctly. Always follow the manufacturer’s safety guidelines.

Q: What’s the difference between a grate heater and a wood burning insert?

A: A grate heater is a cost-effective, add-on heat exchanger. A wood burning insert is a full replacement system that offers more heat but at a much higher price point.