How Does A Fireplace Blower Work?

Fireplace blowers use the warmth created by your fireplace to deliver warm air to the back of the room.

We know what you’re thinking, but no, that’s not the same as a space heater. A space heater just warms the air nearest to it and lets physics do the rest. Fireplace fans actively cycle the whole of the air in the room around the firebox, pushing up the overall ambient temperature of the room.

How does that work?

OK. A fireplace blower is essentially a fan. Depending on the model you have, it will either be mounted on the outside of the fireplace, or sometimes, inside the unit but outside the firebox.

The fan pulls air from the room and directs it around the blower’s firebox. The firebox heats up the air, and then the fan pushes the air back out into the room.

There’s no increase in the overall BTU output of the fireplace – after all, you’re not adding any fuel to the fire. But the air temperature in the room increases gradually.

Why doesn’t it just warm up the air immediately in front of it? Because warm air begins a process known as convection. The warmed-up air rises towards the ceiling. As it does so, it pushes the colder air from the top of the room around and down, ready to be drawn into the firebox, and begin the process again.

That’s a whole different process to simply having a fan push warm air into the room.

Setting up convection currents means that over time, all the air in the room is eventually warmed, rather than just a section near the fireplace. By the time enough air in the room has been heated that you’re pulling already warm air into the firebox, you’ve set up an ongoing process, where the room gets progressively warmer and warmer.

If you don’t have a fan acting as a fireplace blower, your fireplace will be relying on just radiant heat, rather than convective heat, to warm up the room. That’s a slower process, because radiant heat warms up everything in a direct path.

That includes furniture, people, and everything else in the room. Everything the heat hits absorbs some of the heat – people feel hotter, for instance, when they stand in front of the fire than they do at the back of the room.

That means the efficiency of the fireplace in warming up the air is reduced. It will still re-radiate the heat, yes, but it will do it in a relatively inefficient way.

Adding a fireplace blower to your fireplace helps you get the best of both heating worlds – you get the radiant direct action of the standard fireplace, and the convective action of the blower to warm the whole room – without substantially adding to the cost, as you’re not adding extra fuel to your fire, just enough power to run the fan. 

If I have a standard fireplace, can I add a blower?

The short answer is yes, you can. Whether you have a gas fireplace or a wood one, an insert or a stove, you’ll usually find a fireplace blower you can use to boost the efficiency of your fireplace. Find a fan that’s rated to fit your fireplace, and you have two options.

Either make sure you follow the installation instructions to the letter, or – and there’s no level on which this is not the preferred option – get yourself a certified fireplace dealer to install it for you, so you can be sure it’s done correctly.

That way, you can also be sure it’s installed levelly, and won’t rattle when you use it. That’s important if you want to maintain your mental health while the fireplace blower is in action.

If you install the blower yourself and, not to put too fine a point on it, do it wrong, you’re going to end up with a rattling fan. If that happens, contact a certified fireplace service center, and get it inspected.

Frequently, the issue is down to vibration between the fan and the fireplace. Get an expert in and they’ll adjust the placement, or add buffers between the two elements, to eliminate the noise issues.

That’s why, on many levels, going with a professional installer at the start is the better option.

Naturally, if you have it in your mind to add a blower to your fireplace when you’re buying your fireplace, make sure you get one that works with a blower. Otherwise, you can try to blow all you like, you won’t warm up your room in anything like the time you otherwise would.

Naturally, while fireplace blowers make a great deal of economic sense, you can still run a fireplace without one. It’s just that a fireplace blower will give you warmer air all around the room through those cunning convection currents, rather than making your fireplace strain to warm up the same volume of air by radiation alone.  

What if I have a wood stove?

You can still use a fireplace blower with a wood stove, but you will need to be a little more cunning about it, and use an additional accessory like an airmate.

Usually with fireplaces and inserts, you have an automatic channel between the firebox and the outside of the fireplace for the warmed air to go through. With a freestanding wood stove, you’re not dealing with the same level of sophistication.

But by adding an airmate, you give the stove the same sort of channel to push out the warmed air and start your convective heating of the room.

And before you ask, no, having a blower and an airmate doesn’t affect anything about the efficiency of your wood stove. The efficiency’s the same, the burn time and the heat output are the same – or at least, they’re as near the same as makes no practical difference to people in the room.

As with fireplaces, you’re not adding or removing any fuel from the burning process. The only thing you’re doing is passing air through the element that heats up. There’s practically no energy lost in the process, because your stove will be heating up the air around it anyway.

All you’re doing is then making sure that the heated air serves a dual purpose by being pumped back into the room, raising the ambient temperature on the way.