Log Burner Fan - Any point?

[Boobonman]

Pondering ways to make the log burner we have in the lounge more efficient, its an absolute furnace but the heat is very localized.

Wondered if anyone had any experience of the stove top fans that start spinning when up to temperature to supposedly move the hot air further into the home, I understand what they claim to do but a bit dubious if one would make any noticeable difference. Amazon reviews are either people saying they are amazing or people saying not to waste your money...

[lizardbrain]

I think they are meant to make temperature slightly more consistent in the room. We have one but I can't tell the difference.

For us, the point of the fire is inconsistency, sitting next to it and feeling the difference in temp. Otherwise we would just put the gas up.

[shtu]

Don't expect an immense difference. The draught they produce is enough to blow out a match or lighter from a few inches away, but it's far less than eg, a small desk fan.

[Nath911t]

I use a 12" desk top fan that we bought some time ago for the summer and point that towards the side/back of the stove. Just switch it on every now and again to circulate the heat. We have 2 of the stove top fans and they are good for collecting dust.

[austinsmirk]

Yes. Have a stove plus modern two zone central heating.

I’d say it made us use the c h at 0.5 degrees c less.

Doesn’t sound like much but it adds up. You can feel a difference I think, shifts the air. Certainly it can be spinning like an aircraft prop at some points.

For £20/30, hardly a costly mistake to try.

[fouroaks]

This looks more PH style https://www.stirlingengine.co.uk/d.asp?product=VUL...

[SlimJ]

Nath911t said:

I use a 12" desk top fan that we bought some time ago for the summer and point that towards the side/back of the stove. Just switch it on every now and again to circulate the heat. We have 2 of the stove top fans and they are good for collecting dust.

I've tried this with a regular fan and by pointing a fan at the stove you circulate the heat around the room quicker. Also tried this to see if we could push more of the hot air up stairs (worked pretty well).

As for the fans that sit on the stove, we have one and find it makes a slight difference in pushing hot air out in to the room, but certainly not to the same effect as an electric fan.

[Snow and Rocks]

We have a stove top fan but i'm not convinced it makes a blind bit of difference. The convection currents set up by your stove itself will be much stronger.

We do however, have a large ceiling fan gently ticking over which makes a huge (easily measurable) difference. The stove is at one end of a long rambling open plan area and it makes the difference between being freezing at the far end and sitting comfortably in short sleeves.

[Traffic]

We have installed a couple of these types of airmovers https://airmove.se/

I have it set to 22c so when the temp hits that level then it starts to transport the air to neighbouring rooms.

[Evoluzione]

It was discussed at length last month. The initial (but not final) conclusion was that cheap ones would do more good inside the stove, rather than outside it, but that a really expensive one may do something, but it would be difficult to prove.

[Panamax]

I'm deeply sceptical. It seems to me the "fan" isn't pushing any air anywhere - it's just reacting to the natural movement of hot air that's already taking place.

They look pretty, though.

[Scolmore]

I've not used one, but have been looking at this product: https://www.recoheat.co.uk/

[HotJambalaya]

Traffic said:

We have installed a couple of these types of airmovers https://airmove.se/

I have it set to 22c so when the temp hits that level then it starts to transport the air to neighbouring rooms.

Thats actually very interesting. My living room has my wood burner in it, and it always annoys me that I cant benefit from the heat in my bedroom. Opening the door to my living room means all the heat is wasted since it goes straight up stairs. I'm assuming that sticking one of these in the living room and running the tubing through the ceiling and out into the bedroom would be what this does?

How much is a kit?

[lizardbrain]

Thinking about it, our burner heats up the radiators, so it's doubly pointless having a fan. Going to bin it this eve!

[Traffic]

HotJambalaya said:

Traffic said:

We have installed a couple of these types of airmovers https://airmove.se/

I have it set to 22c so when the temp hits that level then it starts to transport the air to neighbouring rooms.

Thats actually very interesting. My living room has my wood burner in it, and it always annoys me that I cant benefit from the heat in my bedroom. Opening the door to my living room means all the heat is wasted since it goes straight up stairs. I'm assuming that sticking one of these in the living room and running the tubing through the ceiling and out into the bedroom would be what this does?

How much is a kit?

They sell two types I believe, one for through-walls and one for through ceilings, I think they are both sub £200.

[Desiderata]

Panamax said:

I'm deeply sceptical. It seems to me the "fan" isn't pushing any air anywhere - it's just reacting to the natural movement of hot air that's already taking place.

They look pretty, though.

Most of the common ones use Peletier motors, a low voltage electric motor run from power produced by thermodynamic heat transfer across wafers of superconductors. I never realised this until we were given one as a present. Like you, I'd assumed that the blades were turned by movement of hot air and therefore not much good.
Our woodburner is in a high ceilinged room (4m) and the fan does a great job of circulating the air so that the heat is pretty consistent at all levels rather than just warming the top few feet where the spiders live.

[Crudeoink]

A lot of these cheap stove top fans use a TEC peltier to produce the energy to move the fan, even at a temperature differential of 175°c they only seem to output 0.5w. There more expensive TEG peltiers can output over 5w of power, but these are about £30 each. I played around with making a phone charger for camping that uses a peltier to charge a phone with a baked beans tin filled with how coals so did a bit of reading into peltiers! I'd imagine these stove top fans only produce enough power to spin the blades, without moving a meaningful amount of air really. My pretty wimpy desktop fan is 35w, so 70x more powerful than a cheaper peltier output and 7x more powerful than an expensive peltiers output

[Simpo Two]

Mine pushes a useful amount of hot air from the inside of the recess out into the room. It certainly lifts a piece of paper put in front of it.

Obviously an electric fan will achieve much more, but the point of these is that they work from just the heat of the stove.

[HotJambalaya]

I have one, i was pretty sure it did nothing until the other day when i was leaning on the mantle with one arm in front of the fan and one on the side without it, i definitely felt a bit warmer on that side. So i switched it and it followed.

Cant recall where but on one of the threads here someone was showing a cowl that theyd made for theirs and said it gave much better air. Perhaps on the main woodburner thread?

[AW10]

Our lounge was extended by the PO so the wood burner is off centre. We have one of these blowing at the wood burner at a 45 degree angle from about a metre away https://www.meaco.com/products/meacofan-260c-cordl...

It seems to do a good job to distribute the heat around the room and at its lowest setting it’s just about inaudible. Bonus is that it can be used in the summer as well.