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UFH in a large shed


Paul H

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Hello
I'm looking to put some heating in a large shed/workshop 10mx5m mainly to keep condensation down and take the edge off low winter temps.
As the floor needs levelling and insulating my first thoughts were to put in the pipes for hot water and use an electric water boiler of about 7Kw
Then I thought why not just put the electric heating matt .I don't want to raise the floor level too much so I can't put 4 inches of Kingspan and then 65mm of screed .
How about 30mm of Kingspan 25mm screed followed by some large stone tiles ??

Thanks

Paul

 

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You will lose a massive amount of heat into the ground, so UFH would be really inefficient, whether you use electric heating mat or a wet system.  As you're already committed to using expensive electricity, I would have thought a much more efficient heating system, like panel heaters, or ceiling mounted infrared heaters, would be a much better bet, and would cost a lot less to run.

 

UFH makes for a higher comfort level when it's on for long periods of time, but even with a lot of insulation underneath it there will always be some heat lost into the ground, so UFH is never the most efficient heating method, really.  In a house, the loss of efficiency is OK, as the convenience of not having radiators on the walls, plus the added comfort level, more than compensates for the inefficiency, but it would not be a good choice for a workshop, IMHO.

 

If you're going to be working in there in cold weather, then radiant heaters are a good choice, as they will make you feel warm pretty quickly, even though the air temperature in there may be a bit chilly.  This is why warehouses and large workshops tend to use radiant heating; they don't need to heat the air up to a comfortable temperature in order for people to feel warm enough.  Radiant heaters also have the advantage of being near-instant in their effect, useful for a workshop, where you want to feel comfortable shortly after turning the heat on.

 

As an aside, we have UFH in our house, with 300mm of EPS insulation underneath it, yet it still loses close to 10% of the heat that goes into it through the ground beneath.

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8 minutes ago, Onoff said:

Make a bfo warm air panel heater from scrap and strap to the side of the shed. Some of the lads here have snow on the ground:

 

https://simplysolar.supporttopics.com

 

Years ago, when I was forever working on cars in my workshop,  I made a waste oil heater out of steel scrap.  It used a drip feed and a vaporisation plate that worked very well indeed.  The thing was started up by chucking a petrol-soaked rag into the bottom, lighting it, then waiting for the plate to get hot enough before turning on the waste oil feed.  The only snag with the thing was that as it heated up the oil in the feed would thin out and the flow rate would increase, so it tended to suffer from thermal runaway.  The trick was to keep an eye on it for the first half hour or so and keep turning the oil valve down a bit as it warmed up.  At full throttle the thing would get the 1/4" thick welded steel tube case glowing red, and it was all free heat from old engine oil.  Saved having to get rid of the old engine oil, too, but it probably wasn't the most environmentally friendly way of heating the place.

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Oh @JSHarris you have got me thinking now about my workshop heating. After three years of nothing but building I am going to spend some quality (retired) workshop time working on my grey furgie and classic car this spring whilst waiting fir the ground to dry out so I can start landscaping. Can anyone link me to a good build for one of these heaters please (I have some scrap gas bottles!!).

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I built mine in the pre-internet era, around 1977/78, and used plans that I think were in one of the car magazines, not sure which one.  They are all much the same though, and use either a pan type burner or a centre-fed disc burner.  At the time I built mine the disc type was thought to be easier to clean, as they do tend to coke up a bit, especially if not run pretty hot.  IIRC, the tricky bit was getting the air feed right, as the secret is to have a low temperature burn where the oil runs in, with a much higher temperature burn above that, in the main chamber.

 

Mine was made from around 4ft of scrap 12" diameter, 1/4" wall thickness steel tube, with plates welded on top and bottom, and a bit of 4" steel pipe welded on the top as the flue, which went straight up through the wrinkly tin roof.  There was a hinged door on the side to get at the burner, plus air holes drilled through the lower part of the case, which was held around 2ft off the floor on angle iron legs.  Sadly I don't have any drawings of it, but I'd guess a look around the web will probably find some, as they have been around a long time.

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42 minutes ago, joe90 said:

Oh @JSHarris you have got me thinking now about my workshop heating. After three years of nothing but building I am going to spend some quality (retired) workshop time working on my grey furgie and classic car this spring whilst waiting fir the ground to dry out so I can start landscaping. Can anyone link me to a good build for one of these heaters please (I have some scrap gas bottles!!).

 

Enjoy:

 

https://www.mig-welding.co.uk/forum/forums/woodburners-stoves.73/

 

Specifically:

 

https://www.mig-welding.co.uk/forum/threads/waste-oil-heater.57695/

Edited by Onoff
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