top of page

FAQ

Our Recoheat stove heat recovery unit is CE marked for installation under Building Regulations and fabricated to European and British standards BS EN 1856-2:2009

Please download the performance and compliance test report using the button above.

There are always a lot of questions about our lovely product: it's very innovative and seems to promise more than is possible. Usually, if something's too good to be true, it isn't - but in our case the principles are actually perfectly reasonable in terms of the physics and the functions.

So below, we've put together some Frequently Asked Questions. If you have any others, please do ask them, through the website or on our social media - we're Recoheat on Facebook and Instagram.

Can I install the unit myself?

Stove flues are delicate instruments, and the Recoheat fits inside it. It therefore needs to be installed and maintained by a competent person. Your local sweep or installer is an expert you can rely on to keep the unit, and you, safe.

In the first instance, it's always best to use the qualified person who installed your stove to fit the Recoheat, or to ask your regular sweep. We also have a list of registered sweeps and installers you can call on, on the website at www.recoheat.co.uk/installers, or you can go to the Hetas website and find someone in your area. Hetas has a search function here: https://www.hetas.co.uk/consumer/services/installers/

If you're still struggling, contact us and we can help you find someone in your area.

Can the system be fitted to stoves with a rear-mounted flue?

Yes, they can, as long as it has a T section with a soot hatch fitted. Mounting them on the rear works very well on a properly set up stove: the output temperature may be slightly lower, but the air blows across more of the surface of the stove, so the over-all effect is the same. You will need to check that the operating temperature of the flue at that point is about 250 degrees. You'll find more information on our YouTube channel, but always get in touch and send us pictures of your installation if you want detailed advice.

How noisy are the pumps?

The aquarium pumps we supply are designated super-silent, and they are in a normal situation. When they're fitted to the Recoheat though, the sound is amplified so that they do make a noise in the same way a large fish tank pump does: not loud, but certainly noticeable in a quiet room. To get around this, we make and supply a sound suppressor as standard, which pretty much takes the hum out completely.

 

The sound that does remain is the hiss of air coming through the outlet pipe, which increases as the heat and subsequent speed of air flow increases. This is caused by the turbulence in the air jet  that is the reason the device works so effectively, and it acts to draw heat away from the stove into the rest of the room. The rapid flow of heated air pressurises the air in the room and spreads the heat by rapid exchange as the temperature and pressure equalises.

You can listen to the sound on our videos to get an idea of the levels, and the relative pleasures of hearing heat and money pour into your home! The hiss is considerably louder than normal when we have the thermometer probe in the air flow, so it's actually a lot quieter than most of the videos.

How much electricity does the pump use?

The pumps we supply are rated at 37 watts but run at 17 watts to operate at just under 60 litres per minute - so less than an old-fashioned light bulb.

To compare, you'll use much the same electricity in a week that you'll use boiling a kettle once.

Does the unit need maintenance?

No, the unit doesn't, except in terms of cleaning when you sweep your flue. We recommend doing your first sweep after installation in half the time of your usual regime, just to check everything is running normally.

 

As for the pump, we supply the system with one of the most popular large aquarium air pumps on the market - famed for its reliability and designed for silent operation. It can be replaced with another pump if it fails after the warranty period (during which we will replace it), and replacing it is just a matter of unplugging it.

The system can't possibly double the heat output of the stove, can it?

Oh yes - partly because of the heat output, partly because of the change in air flow, and partly because of the period of time it delivers heat for. It seems implausible if you think of the stove as having to produce more heat, but it's not. We're recovering heat from directly above the heat source, in the hottest part of the stove and pumping that straight out into the room.

 

That's why it pumps hot air as soon as the fire is lit: you'll know that the flame is hot at that point, even though the heat hasn't begun to warm the stove. It's also why it continues to pump hot air for hours after you've stopped putting fuel in the stove: as the stove cools, the heat concentrates in the middle and continues to pass up the chimney as part of the cooling process.

 

But don't take our word for it: check out our videos to see it in action, and in particular, check our TrustPilot reviews at https://uk.trustpilot.com/review/recoheat.co.uk

 

We've now got a marvellous review from the stove review channel The Tortoise on YouTube at  https://www.youtube.com/watch?v=aozq33bJojE 

 

You can also refer to the testimony of stove expert Sam Hamer. He now heats his showroom in northern England with one stove instead of two, because that stove is running a Recoheat. So that's an easy calculation. The video is here: https://youtu.be/LbMzmdYHVgI

How much fuel will I save, and why?

You save fuel because you don't have to burn so much, for so long, to transfer much more heat into your room because you stop having to use heat-driven convection to circulate the warm air and transfer its heat into the rest of the room.

Your stove works by collecting heat from the fire in the steel or cast-iron body, and releasing it by radiant heat transfer into a convection-driven air-flow into the room. That's why it's much more efficient than an open fire. 

But the Recoheat recovers the direct heat from the exhaust and actively pumps that into the room, and the jet of hot air draws the stove heat with it into the room. The flames, however small, are producing more than 500 degrees of heat at the bottom of the flue where we gather it, and that's all we're using. The system doesn't need a big fire to operate exactly the same, because the combustion temperature doesn't drop much and when the stove temperature drops and reduces the convection-flow of air, we're still pumping it out into the room.

On a large stove, the fuel saving is more than on a small stove because the stove hasn't got to be as hot to achieve a much better heat transfer than without the pump. Our customer with the biggest stove - a Hunter Herald 80b 17 - 21kw output - reckons she's using a third of the fuel to achieve an even warmth across her whole large room so that it's comfortable for the first time ever in winter. For a 1605 house, that's quite an achievement!

Does the unit trap soot in the flue?

No, they don't because of the way the coil functions in the flow of gases. The coil is a tube, with round edges, obviously. As the flue gases rise past the edges, they accelerate in the same way wind does over a wing: this foiling effect then causes vortices between the rings of the coil called Von Karman vortices. This acceleration and agitation of the particles, combined with the heat of the coil placed in the hottest part of the vent, discourages the build up of soot to such an extent the unit will remain visibly cleaner than the flue.

 

The only rider to this is that if your flue is not functioning properly and is condensing in the lower sections, the coil will provide an additional surface for soot to gather on. In this instance, don't fit the Recoheat, and fix your installation as it is dangerous. A sweep is the best person to advise on this.

Does the unit slow or cool the up-draught in the chimney and cause problems?

No, it doesn't. This was a key part of the BSRIA external testing: they measured the flow and temperature right up the 4.5m flue and could detect no variation with the unit running or not. The certificate they issued is available on the Installation page.

Again, there's a good reason for this: the coil creates turbulence in the gases, which reduces pressure on them. At the same time, the heat extraction is minimal because it is controlled simply by the surface area of the coil, which is the equivalent of an extra 10cm of single skin flue on a 5" flue, and 6cm on a 6" flue. All flues have to deal with far variation in height than this tiny amount, so have to be able to deal with our units.

Can I extend the pipes on the system and pump the air into another room?

No you can't. The reason for this is that the device works by exploiting the phenomenon of a turbulent barrier layer. Basically, turbulent air transfers heat much faster because heat is passed from molecule to molecule. In a normal air flow, the molecules sail along, and only come into contact with the molecules either side of them. If you make the air turbulent, the molecules bounce around hitting loads of other molecules and transferring their heat exponentially faster. So it transfers heat really efficiently from the hot steel of the coil, but equally well into the cold material of anything it then comes into contact with.

So use air to move the heat by opening your doors or putting in vents to other areas - that does work really well.

As an example, one of our customers is using their Recoheat to warm their conservatory from the stove in the adjacent room and reported that it has transformed the warmth to the extent it is actually warm out there in the winter. That's what we're talkin' about!

Can you clean the flue with the unit installed?

Yes - the gap in the middle is 65mm, so you clean the flue with a professional brass-headed rotating power brush. You then clean the coil itself with a mole (small soft chimney brush).
 

The plastic rotating brushes don't go through - or rather you might get them up, but they won't come down, so you'll probably need to use a professional sweep, or  clean the chimney via an access hatch, by using an adjustable section above the Recoheat that you can open to clean, or clean it from above. That's obviously the easiest way on a log cabin, tiny-house, motorhome or boat set-up in any case.

Does the system comply with British and European manufacturing standards?

Yes, it does: it's manufactured to BS EN-1856-2-2009 and it is CE marked. It is not currently Hetas approved, but doesn't need to be as they are a delegated authority for building regs compliance rather than an approval or regulatory body as is sometimes represented. We will apply for approval when we've produced a complete study of the units by external engineers.

Is Recoheat manufactured in the UK?

Yes, it is - completely. We don't make the air pumps or fittings, but the units themselves are made by hand in the UK. The product was born in Burnley, and our new base is in Suffolk.

Does the system blow flumes into the room?

No. The air blowing through the unit never comes into contact with the air or smoke in the stove or flue: it passes through a sealed unit.

Where have you been all my life?

We know how you feel - we all love having a fire as the heart of a home, but not the experience of heating a corner of a room and dreading walking away. At least that was always better than the hot front and cold back experience of an open fire, but there had to be a warmer way! 

 

So now there is - reclaim the flame with Recoheat!

 

Come and join the warmest revolution since cheap flights to Spain.

GOT A QUESTION?

Contact us on social media or email us - we'd love to hear from you.

Email us at sales@recoheat.co.uk, fill in the contact form, or connect with us on social media - we're Recoheat.

bottom of page