Cool (hot) idea homemade underfloor heating from wood stove

The way I made my wooden stove heat up water for the underfloor heating.

[@mhpjii]

Bjarke, _please_ provide a detailed diagram or diagrams of your complete system (hot water & in-floor heating) for the worldwide audience that wants to learn in detail about your vision. Thank you.

[@DonnDIY]

That's a great simple system (the more simple the better in my opinion 😉). I'm probably gonna have to do something similar with my workshop radiant floor heating. Thanks for the full overview of the system! 💪

[@mhpjii]

Donn, please be in touch with Bjarke and build his hot water & in-floor heating systems on your channel. This is fascinating.

[@skogljus]

You are so smart! Thank you so much for sharing this. I would love to have the same kind of system in my house

[@davidmingee1295]

Thanks for the video. And great work.

[@londel1767]

very nice system. I'm hoping to do a system like that for my cabin.

[@falcolombardi1000]

Hi Bjarke. Fellow Dane here, Nice system! How many square meters are you heating up with this? And how long does it take for it to send hot water to the floor, from when you start the fire?

[@786otto]

Good project, you did a lot of plumbing.

[@MarkThomas123]

I would like to install some radiant heat in my blacksmith shop. Dirt Floor, so it is easy to do.. I have some questions to understand your setup... 1) Any time the stove is hot the water cycles itself, heating the water in the red tank. (Thermocycles?) 2) The Thermostat for the main pump reads the temperature of the Water in the main(Red Tank). Correct? Turns on at 30 degrees. This circulates through the house floors and pushes water back into the red tank (Return of cooler water). 3) There is a fixed amount of water in the system, and no running water from a well or city/county water system? It seems, the water level does not go down, or goes down very slowly, maybe from evaporation at the Expansion chamber?? Which appears to be the only opening in the system, that is there for safety, but, water should never leak out of the expansion chamber, or at least never expand to the point that it fills up the expansion chamber and overflow bucket.. Correct? 4) During operation.. Is there water above the top of the red tank "usually"? The Air bleed off tube, at water temps of approx 30 degrees (Normal Operation). Does it usually have water above the red tank, in the pipe going to the bottom of the Expansion chamber and at some level also in the Copper Air tube? Meaning that the system(Red Tank), is completely full at summer time (No heat from the stove) (regular house temperature water).. Or, when the water is heated, it is actually at some level in the Expansion chamber so you can monitor your "System Water Level"? If not, how would you know the system was running low on water? I think maybe I can answer that question... ? The water going to the main pump pulls from the top of the red tank... Also, the hot water from the stove runs into the top of the Red Tank.. I can't see the pipe entry points in the video.. Maybe they both come off of the same pipe sticking out of the top of the tank? So, you would hear water dripping from the hot water feed from the stove, or, you might also hear the pump cavitating air instead of full water at the pump when it turns on? 5) Understanding the Tubing in the Pump Room.. There seems to be two Manifolds needed.. One for the water supply to the floor that all pipes start the warm water flow, and another "Return Manifold", where all pipes return the cooler water.. I think the top gray flexible pipe brings hot water from the red tank into the pump, then, through the manifold and out to warm the house.. Then, the gray tube coming from below going to the Temperature gauge to the Right of the hot water feed, then back to the tank through the bare copper line.. To the left is where you added the second Thermostat (This one is a valve that opens when the water is below 30 degrees, and water only moves back to the tank when the pump is running.. Correct? Question.. Where is the temperature sensor on this valve? Because, the water returning from the house (cooler now - maybe below 30 degrees often, would open the valve and mix with the hot water???? That seems like it would not be good.. Maybe the valve is only a one way valve? Only lets water go from the hot(Left) to right? And, never from the Right to Left? Because, any time the pump is running, it could possibly cause the return water to mix with the Hot water?? But, you mentioned keeping the water a constant temperature, so, mixing the hot tank water with the return water may be what you wanted? Maybe it is nicer to have the house warm up slowly and more evenly? I think I like your design... I have been looking at "Wood Stove Heat your Water Videos", and I can see all sorts of problems associated with the copper coils. Your design is very clean and I think the tube that you created above your stove is very efficient and must have a lot more flow than a copper pipe setup and heat up much faster.. And, I think, must pull much more heat out of the flue pipe before going out of the house. If the stove is efficient as you say, the heat in the flue is not needed and is ready to be pulled for better use inside the cabin.. I think an excellent system design.. I have not understood this type of system until your video.. The time you took to video and upload is much appreciated.. I know how much time it takes.. Quick videos that can be done on the cell phone all at one time in one video is all I take time to upload anymore.. Too busy.. One request.. If you do more videos, please turn your camera sideways, so the video fills the screen and is much larger.. I could have seen more details and maybe not need to confirm these things with you.. I think any of your audience might enjoy reading my assumptions and questions, if you would be so kind to honor us with some answers. Hopefully, there are a lot of numbers with Correct behind them, and not so much explanations to correct me.. Maybe on the last part.. I did not fully understand that part, but would like to.. Then, I can start planning for my build.. Thank you from the USA.. North Carolina.. Cheers. !!

[@amorfo9127]

I agree on points 1,2,3...but: 4) Red tank is full of (hot) water AND expansion tank (non circulating 4/5 liters) it's full up to the black mark on the hose on the right even if the stove is off, is not dangerous cuz from...44 liters it only expands half a liter (thats why he says expansion tank could be more small), no dripping in the bucket unless water in red tank will really boil which never happens cuz the stove "water heat system" is not that powerfull (to boil 44 liters you need much more heat). The "Air bleed off tube" is half full of water (again black mark level), pump take hot water from the top of red tank (you can see the hose barely on 6:53 ) AND red tank takes hot water from the stove from the brown pipe in the front a little below. 5) Your description is correct until: "To the left is where you added the second Thermostat This one is a valve that opens when the water is below 30 degrees" no, it CLOSE when water is below 30 degrees, so that the "cold" water goes only out through the return pipe to the bottom of the red tank meanwhile hot water from the top goes to the pump. When the valve is OPEN because water on floor is hot enough (here comes my problem), it is assumed that the water circulates in the "closed" circuit from the floor BUT as I see it IS NOT a closed circuit...with the valve open pump can suck cold water from the return pipe (which you don't want) OR can pump the (already heat enough) water through the return pipe to the red tank (which you also don't want cuz your floor is hot enough, and doing this you heat it even more which could be a problem). From my guess the pipe system doesn't really regulate "to the desired" degree...it just heat water and make it run on pipes, IF in the red tank water gets hotter lets say 60 degrees (you don't want that water on your floor pipes) it will goes through on 60 degrees no matter if you put "30" in your thermostat (cuz pump once on is always on (unless you turn off the stove ) and valve don't really close the incoming hot water when floor is hot enough), now...with this system maybe water NEVER gets that hot so it could be ok, but in all cases the (expensive) valve is not closing the circuit and the pump is probably mixing all the time all the water in the system...it heats the floor anyway, not as expected but it heats.

[@MarkThomas123]

@@amorfo9127 #5 your description and following two paragraphs.. I think, the second valve (Confusing Valve) letting the cold water into the hot, he did say, mixing the water and he also made me think that he had plenty of hot water.. So, I think you are right, when you say, that, I think,, he is mixing the water to keep the heat lower and maybe the volume of the tank/floor lines, etc,, is just about the right size for the total system of heating.. That the average amount of heat the stove is giving off is sufficient to heat the cabin area, but, not too hot, and, mixing the cold and hot water and circulating it, probably once the system is fully operational and water continuously circulating, the mixing of the cold and hot is the right temperature to keep the cabin at a perfect level.. Maybe it was luck, that the system matched perfectly, or, he has been working on this system for quite some time and has it balanced.. I think, maybe, he knew the proper size for his type of cabin, maybe from someone else with a similar system, and built it the same or close to the same way.. There really is no need to circulate super hot water through the system, if the cabin is insulated well, and the stove really does not "Boil" the water much or at all.. Maybe, just some at times.. Then, mixing at that point makes more sense... I think the pumps are fixed volume pumps.. I had some things happen, and was not able to finish my project.. I put it off until next fall/winter.. But, my thought was, the area I am in now could use much more heat, but, the shop I am building after I figure this out will not need anywhere as much heat as this one, so, I was considering that, when I was looking into this.. Because of your description, I think, I was correct in assuming that.. I think, he has the correct volume of water for the amount of heat he usually generates from the wood stove, which is more than what he needs, so, he mixes the return water with the hot, so, he has water temperatures closer to what he wants to not over heat the water, but, is able to continually circulate it, and keep the upper water supply system at a good temperature, not to over heat and boil it.. He did say, it was there as an overflow, but, it never overflowed.. So, maybe, the system is just the right or perfect size for his stove/cabin/hot water storage and floor combination.. This is very new to me.. I am only developing the concept, so, I can play with it and experiment with it until I fully understand it and can build something under the cement.. Right now, I have a blacksmith shop with a dirt floor, so, I can play with the system size, etc.. I will be running a waste oil burner and I played with the design until I can run it very hot, or, I can run it at a low volume, once things are warm.. I will be playing with the water jacket size more than hot water holding tank, and I was going to install a second pump, and pump the water through a radiator with a large fan behind it, and it should hold the heat, and allow me to take large amounts of heat out of the system as I experiment with it... I will only circulate the water through the floor at the rate it takes to keep the floor warm, but, not hot.. I can rebuild the 4" and 6" water jacket length to play with the overall volume of hot water created to thermocycle to the larger holding tank, and maybe create the perfect matched system, like I think he has done.. What do you think about that Concept? Remember, I have never had one of these systems.. Only thinking how it would work before I build and test my theory... Thank you for your Comment..

[@MarkThomas123]

@@amorfo9127 I made these notes also.. Remember.. He said this. It thermo cycles to a 40 litre tank on the wall.. He said, 20ltrs would have been enough for his radiant heat. So, at 20ltrs, he would probably have more trouble regulating the heat and have boiling problems.. But, if he is able to keep the 40ltrs cooler, but, hot enough to heat well, a well insulated cabin, the larger volume, more to heat with lots of potential heat, maybe, it is the amount of water that works much better at a lower temperature, but, sufficient to keep the cabin warm.. It is what I was thinking, when he made that comment... It seems this might be the way to get very close to a perfect sized system, considering the amount of heat he would normally run his stove at..

[@MarkThomas123]

@@amorfo9127 I think my question to the producer of the video now would be.. Did you create a 40Ltr system vs a 20ltr system, to make it easier to control the water temperature in the system from getting too hot, and to easily be able to control the temperature at a lower level in the house and to not have problems with the over heating/boiling and over flow volume? I think, if he said, yes, I could answer the rest of the questions.. Still thinking about it.. ha.>Ha.

[@go.gators]

I just found your channel I live in Oregon in the United States.. and I wish I lived off grid.

[@AeriolNicols]

Looks great. What type of wood stove do you have. Wondering if available in Canada.

[@offgridmangogrower]

Nice set up...did you fab the stove pipe jacket? What temp and pressures are you operating at? Sre you gravity or pressure induced? Any flow diagrams ...?

[@tarbaris]

Does wooden floors work well with ufh? N.b. for the boiler and plumbing part, thumbs up

[@casonknipe3961]

Do you get any more creosote in that heating tube than a normal stove pipe?

[@mehmetalikizilkaya3397]

Genialt! Er det et dansk sommerhus?

[@kristofermed1f]

3-4 liters? how much pressuare on the system, i guess if you put a cirkulationspump u dont need to have everything so high upp and the first copper test would have worked? right i want to do something smililar..

[@kristofermed1f]

why self cirkulation and not pump?

[@lewishorsman2219]

I’ve been wondering if I can do that myself without water. Seal the pipes so no air escapes and then the fire hears the pipes thus heating the floor. Is that not safe? No new air would be entering the piping so minimal chance of pipes bursting. With water any leak under the floor would take time to be detected unless you notice steam coming up through the floor.

[@rod4607]

Lewis did you find what you were looking for??

[@lewishorsman2219]

@@rod4607 I have indeed managed to create a system whereby hot air is pumped through underfloor pipes instead of water. Takes no time for air to heat up anyway and no chance of leaks. I have CO monitors under the floor and above and it’s great.

[@rod4607]

@@lewishorsman2219 very impressive. I’m just starting out, just purchased a 10 metre bus. How did you get this done?

[@lewishorsman2219]

@@rod4607 luckily I have a plumber friend. Similar pump used in the video. Took out the flooring, drilled in holes into new floorboards to lay pipes through. No need for insulation around the pipes as you want them to heat the air around them and up through the floor. Imagine laying hot water pipes under your flooring. The pipes are heated via the fire stove which I bracketed the pipes coming up through the floor to the back of the stove, bent the pipe a few times to make sure proper heat dissipation to the pipe. If it’s put through and you don’t maximise the amount of heat through the pipe it took ages.

[@rod4607]

Less heat over larger area. Like rubber gripping the road. It seems...as simple as it seems. Pipes and a pump and a regulator of some sort. Cheers for the idea. I’m going slow with the project. I just bought a business

[@nonyabusiness9747]

So no pump?

[@mistereearly1141]

The water is being heated in an enclosed system? Doesn’t it build pressure and explode?

[@mrrolight]

No. It's not enclosed. There's an expansion tank and a precautionary air/steam escape system that because of the excellent design has never been necessary. I think the guy has done a pretty thorough job. Good question though. Shows you're thinking.

[@mistereearly1141]

mrrolight I answered my own question when I saw the expansion tank

[@mistereearly1141]

Never mind. Just saw the expansion tank

[@adamsmith8058]

I don't understand the heated water on top of the woodburner. It's just a cylinder instead of copper wires and how does the water rise in a cylinder. Don't get that part

[@karimballan5054]

the system is enclosed and there is no air. Also hot water goes up and cold water goes down. So when water gets hot, it goes up. Since there is no room for air, it pulls in cold water from below. So it acts like a pump.

[@lallasjfk]

Great job !!but Get some one else to explaim, so painfull to wattch