Feedback requested on stove gadget

Hi!  I'm considering developing a smart stove fan.
I'm an experienced engineer in Northern Ireland and I'm considering starting up my own business making a few, hopefully useful, things - your feedback will be invaluable in deciding whether to progress this as a product!

The basic idea is this:
A peltier powered fan also has a wifi module and a thermometer.  It would let you know when the temperature goes too high (you've forgotten to turn it down after lighting!) or too low (you need to add more wood)

1.  would you want one?  do you think it would be useful?
2.  are there any particular features you'd like to see in it?  are there any problems you would anticipate?
3.  do you know of any other solution that is already on the market?
4.  how much would you pay for it?
5.  any other feedback welcome!

Thanks a lot - Tristan

Hi Tristan;  Welcome to Permies!

I have lived with wood stoves almost all my life.  A peltier fan is a great addition to any wood stove.
I an old school when it comes to wood stoves. I always know what state my fires are at.
For me the additions you are thinking of adding, would just not be information I needed.
Now a younger more modern (busy) person ,who lives with their phone in hand... they might find this way cool!
I just have to wonder how many of those busy people even use a wood stove?

So for what its worth... there's my feedback.
Good Luck with starting your own new business!

Hi Thomas,

You bring up a good point. I am of the age that I have a cell phone, but I will not see it, let alone use it, for days on end.  That said, I do have 3 wood stoves.  Normally, only one is in use at any given time.  But I would consider such a product.

Hi Tristan,   I'm with Thomas on this one too. No cell phone in the boonies here but use wood stoves all the time. Perhaps you could also make it as a separate add-on feature so that it could be attached to a fan that a person already owns. Like an upgrade to turn a fan into a smart fan?

I would think the WiFi connection would be a dubious addition, given the high heat environment, but if you could come up with a peltier fan that moved greater volumes of air over a significant distance would be a gadget worth buying for me!
Most peltier fans are fairly anemic devices that are only viable in an already well insulated home, I have a 1940's home with Silvawool insulation (R value 2.5!) that has one long common room 40x12 with the stove mounted at one extreme end, the room has a ceiling fan, in cold weather the heat is concentrated within ten feet of the stove and the tapers off to where the other end of the room is uncomfortable and you can feel the cold radiating from the walls (the perfect environment for women enjoying a personal summer!) a box fan in front of the stove on high will homogenize the room even though the ceiling fan doesn't.

If your looking for inspiration an add on Arduino control for pellet stoves comprising of an exhaust detector, a flame detector and a fresh air damper, programmed to keep combustion within a (programmable) percentage of stoichrometric over the variable stages of combustion would sell like hot cakes....probably to the stove manufacturers themselves if not to end users.
Pellet stoves are a smoking (literally!) pain in the ass to keep perfectly regulated, and while their efficiency over a wood stove is irrefutable, the irritation of maintaining them has driven many a proud owner to Craigslist with the bright hope of seeing them out of the house at any cost.

(You can moosage me to send my cut of our inevitable wealth from this collaboration!)

Good luck!

You might want to check out this permaculture channel

thanks everyone so far - it's all valuable feedback

i know the fans aren't great, but lots of people have them and they aren't that expensive... even the guy in the video bashing them had at least 2 lol.  the problem with a kit to add to an existing fan is that there aren't standardised connectors to make it easy - a lot even have the wires soldered rather than a snap on molex connector etc.  the fact they aren't that good makes me fine with the idea of siphoning off some of their power.  i'm not worried about the temperature - the top half of these fans doesn't get too hot.

I think perhaps you guys aren't the target market for this if you rarely use a phone, haha!  I have a reasonably high tech home and would love a phone notification or for [one of my 3] Alexa to tell me "The stove will need more wood in the next 30 minutes".  It sounds like it's more a gadget for the city folks like me!

Tristan Haldane wrote: i'm not worried about the temperature - the top half of these fans doesn't get too hot.

As a first step, you might actually  measure the temperature. As far as I know, commonly available integrated-circuits are not rated for those kinds of temperatures.

Hi Tristan.  Zero engineering experience here.  However as a former homeowner and formerly obsessed with time efficiency, and per statements above, the fan might be the better focus.  A good market to target might be wealthy techies who live remotely, have their own wifi, travel or are away from their home enough to need such a monitoring device.  

There's an app that remotely monitors water catchment.  Another for vault activity (not just surveillance).  Temperature in server rooms.  And so on.  I can envision value in monitoring fans remotely (without the personal need).  For homes, perhaps green houses/nurseries, attic/storage fans.  Swamp coolers.  I would not be surprised if there is already an industrial application.

Joseph - re temperature - I've quite often moved a fan by holding it at the top, and even with the stove roaring away the top of the fan has always been <60C (otherwise I couldn't hold it) which would be fine.
I think definitely it wouldn't be a product for everyone, but there are plenty of stoves sold in cities and the stove seller/installers are an ideal OEM/distributor for it - if the cost were only 50% more than a regular fan (already not very expensive) then I think it could at least be a 'lifestyle business' if not a fortune 500  what do you think?

I have 2 silent Peltier type fans on top of my Blaze King (Anchorage Alaska). Additionally the stove itself has a variable speed fan built in (not silent).
I got tired of bending over to turn it on and off, after 35 years and 200 cords. So I bought a Inkbird thermostatic switch from Amazon. Taped the thermocouple to the back of the air plenum for the fan with heat (very) resistant metal tape.
I played with the settings, it turns on and off automatically, only when there’s enough heat to make the noise of the fan worthwhile.
It only runs continuously when I’ve got the stove turned way up, catalyst bright red. Usually just on really cold nights below -15C.

That’s an interesting idea, thanks for sharing it here! I think adding a temperature sensor could actually make a lot of sense. One of the main weak points of Peltier-based stove fans is the maximum temperature they can tolerate — usually around 340 °C. Beyond that, the TEG module risks permanent damage, so protecting the fan is critical.

For that reason, quite a few existing models include a small bimetal strip in the base that tilts the fan away from the stovetop once it gets too hot. The other common solution is to simply keep a stove thermometer nearby and check it regularly. In that light, a sensor that automatically alerts you to dangerous temperatures would definitely add value, at least in my opinion. The only caveat I’d see is if it required a separate smartphone app — I don’t think most stove owners would find that very practical.

Also, I agree with Bill’s point in the discussion: airflow is still the number one feature people look for in stove fans. If your stove consistently runs above 200 °C, a Stirling engine stove fan is an interesting alternative, since it can deliver stronger airflow without relying on fragile TEGs. There’s a useful write-up on that topic here:
https://stovefanreviews.com/en/a-complete-guide-to-stirling-stove-fans-features-benefits-and-brand-comparison/