jk underfloor heating - retrofit

[mdevilliers]

Does anyone have any experience with or thoughts on the jk underfloor heating and their retrofit system?

 

http://www.jk-gb.com/jk-in-ground-ufh.php

 

We are considering installing into out bungalow refurb plus extension. 

 

[ProDave]

I would want more information.

 

It looks like they just cut grooves into an existing screed and then fit the pipes. What if it is an old house with no insulation at all under the floor screed? How is that going to work and be efficient?

 

 

[Jeremy Harris]

29 minutes ago, ProDave said:

I would want more information.

 

It looks like they just cut grooves into an existing screed and then fit the pipes. What if it is an old house with no insulation at all under the floor screed? How is that going to work and be efficient?

 

 

 

It would be appalling if fitted to something like our old 1988-built bungalow, that's for sure, as that has a concrete floor with no insulation at all underneath, so a large percentage of the heat would just be conducted through the concrete into the ground below and get wasted. 

 

However, if there was a new concrete floor laid onto a decent layer of insulation (say, at least 100 to 150mm of PIR, or more if using EPS) then I guess it would work just fine.

 

The question then would be, why bother?  If laying a new floor anyway it'd be easier to just include the UFH pipes within it, where they are out of harms way.  The thermal response time really isn't going to be significantly improved by having the pipes on top, as most of the heat is still going to flow into the floor slab when the thermostat calls for heat, anyway.  It might make a few minutes difference on a response time of around half an hour to an hour, but I doubt it'd be noticeable in practice.

 

It looks as if it could be expensive, too.  I doubt that special machine is cheap.

Edited February 25, 2017 by JSHarris

[Nickfromwales]

My favourite bit from the website :-

Quote.....

"This means that they can easily be combined with other heating systems already in place because of the low water flow temperature. As a result energy usage is lower and therefore the energy bill, as well."

 

Lol. 

Doesn't mention excessive heat loss through un / poorly insulated slabs etc. 

Also, unless the pipes are grouted in with a very thin wet grout the heat transfer by surface contact area will be dire. 

Doesn't sound like a winner unless you know the history and make up of the floor / insulation, but the worst part is the nonsense in the sales patter. Doesn't sound like they have a clue TBH. 

 

 

[Jeremy Harris]

10 hours ago, Nickfromwales said:

My favourite bit from the website :-

Quote.....

"This means that they can easily be combined with other heating systems already in place because of the low water flow temperature. As a result energy usage is lower and therefore the energy bill, as well."

 

Lol. 

Doesn't mention excessive heat loss through un / poorly insulated slabs etc. 

Also, unless the pipes are grouted in with a very thin wet grout the heat transfer by surface contact area will be dire. 

Doesn't sound like a winner unless you know the history and make up of the floor / insulation, but the worst part is the nonsense in the sales patter. Doesn't sound like they have a clue TBH. 

 

 

 

 

I didn't bother getting that far, but it is a load of tosh, anyway.  If you reduce the flow temperature, as you have to with UFH, it makes no difference to the amount of energy needed to heat the room at all, as that's determined by the heat loss.  Arguably it always increases the losses slightly, too, as the very best UFH will always be slightly less efficient that a heating source that isn't in contact with a thermally conductive outside surface.  With a decent level of insulation underneath UFH this loss can be reduced to a small enough percentage to not really worry about, but it's always there, just the same.

 

It's a bit like the snake oil "voltage optimiser" claims a while back, although I think they've now had to rein in their advertising claims.  They were claiming that by regulating the house supply to a steady low voltage (pretty sure they regulate to just above lowest allowable, around 220V, IIRC) then the energy used would be lower.  In reality all lowering the voltage does for many appliances is result in less power being available, so they stay on longer in order to deliver the fixed amount of energy required.  In the case of something like a kettle, the energy use is actually increased with one of these things fitted, as the lower voltage means a longer time to come to the boil and that means greater heat losses from the case.

 

I'm never quite sure why companies like this seem to think they can just arbitrarily break well-proven laws of physics.

[ProDave]

I even had someone trying to sell me a voltage optimiser to increase the FIT payment from my solar PV. When I questioend them how that would be so, it turns out they were making an assumption, that my inverter would be limited my maximum voltage (which it isn't) and a voltage optimiser would solve that.
 

[Jeremy Harris]

17 minutes ago, ProDave said:

I even had someone trying to sell me a voltage optimiser to increase the FIT payment from my solar PV. When I questioend them how that would be so, it turns out they were making an assumption, that my inverter would be limited my maximum voltage (which it isn't) and a voltage optimiser would solve that.
 

 

 

Late last year I had a similar phone call, trying to sell me a new PV inverter that was claimed to do the same thing.  I wish I'd tagged them along for fun, but at the time I was just annoyed at being cold-called (as we're registered with the TPS and the number is ex-directory).  I just kept asking them where they'd got my phone number from, and in the end was told they had been "given it" by the FIT register.  I have no idea whether someone's hacked the FIT register or whether they really are giving away, or selling, personal data, but either way our number should have been flagged as being TPS registered.  Not worth the effort of chasing it up, as the number they called was the old house, and with luck we'll be moving soon.  Somehow I don't think I'm going to give the new number to the FIT people, though.