UFH why bother when you have photovoltaics

[Donkey Table]

Hi all with the advent of photo voltaics and heat stores, low temp UFH becomes a why bother. Bags of cheap electric and hot water backed up in the heat store, just use radiators. Now Im aware radiators take up space, but consider what happens when you have to fix a UFH system. With rads at worst you unbolt and fit another. Contect the rads to a manifold best of both worlds. A themostat in every room.

With UFH faults is have a stroke time with the potential bills and disruption.

Dont start me on air source heat pumps, thats the devils vegitable. I think they are the next Enron scandal in the making.

Feel free to shoot me down.

 

[Donkey Table]

problem is as the foam shrinks your joints will start to have gaps in them with the possibility of thermal bridging

Well if the foam shrinks, it will do so in flooring too. There is no UV exposure involved, and the foam recipies have improved. If shrinkage is a problem now, cavity walls are the least of our trouble. Screeds will feel it too. If I had my time again I may use a Rockwool cavity fill, only because of the sound attenuation.

 

[ShaunCorbs]

That’s why your supposed to do a min of two layers and staggered joints eg first layer left to right next layer up and down (join)

 

[Donkey Table]

That’s why your supposed to do a min of two layers and staggered joints eg first layer left to right next layer up and down (join)

No Celotex technical says single layer. Double layer of say for example 75mm to make up 150mm increase the cost greatly. The staggered joints is a common pattern, this was done with the cavity bats too. In addition if you have multiple layers of differing materials, in this case an extra two laters of foil at the 75mm middle point, you need to do a dew point calculation for the building inspector, to be on the safe side.

 

[Ric2013]

No Celotex technical says single layer. Double layer of say for example 75mm to make up 150mm increase the cost greatly. The staggered joints is a common pattern, this was done with the cavity bats too. In addition if you have multiple layers of differing materials, in this case an extra two laters of foil at the 75mm middle point, you need to do a dew point calculation for the building inspector, to be on the safe side.

A dew point calculation shouldn't be a difficult operation, surely?

That said, if foam shrinks, then I'd suggest it's not going to perform well. Not so much cold bridging as air simply convecting around it. Will know more if I ever lift a floorboard in my lounge.

 

[Donkey Table]

A dew point calculation shouldn't be a difficult operation, surely?

That said, if foam shrinks, then I'd suggest it's not going to perform well. Not so much cold bridging as air simply convecting around it. Will know more if I ever lift a floorboard in my lounge.

Yes the foil acts as a vapour control layer. However do you also silver foil tape the first layer, more cost. In which case the whole buscuit is open to any vapour in the area. I was asked for a dew point calculation for my roof insulation composite. All the beam and block foors Ive seen done used a single sheet of the required thickness.

 

[Donkey Table]

A dew point calculation shouldn't be a difficult operation, surely?

That said, if foam shrinks, then I'd suggest it's not going to perform well. Not so much cold bridging as air simply convecting around it. Will know more if I ever lift a floorboard in my lounge.

Ric is your floor floating T&G? ie 22mm.

 

[gpbeck]

I remember when this was a plumbing forum.

 

[Donkey Table]

I remember when this was a plumbing forum.

I remember when this was a plumbing forum.

It all forms part of the system GB. The discusson centers on UHF and to a lesser degree ASHP, and its potential for complexity and large bills. There has been an interesting and valid input from our esteemed contributors.

I must ask if UHF vanished tomorrow, would your pension plan vanish with it.

 

[Ric2013]

Ric is your floor floating T&G? ie 22mm.

No. It's square edged pine on a suspended floor and screwed to the joists. The Recticel was placed between the existing (historical) joists and edges and joints gunned.

It all forms part of the system GB. The discusson centers on UHF and to a lesser degree ASHP, and its potential for complexity and large bills. There has been an interesting and valid input from our esteemed contributors.

I must ask if UHF vanished tomorrow, would your pension plan vanish with it.

Agree this discussion does indeed have relevence to plumbing.

Not sure why you think plumbers view UFH as a get-rich quick scheme. It tends to be something people aspire to have, but I would not imagine plumbers are able to charge more for the labour involved in UFH installations than for other plumbing tasks. If you like radiators, then you're right to fit them. Personally I prefer the old single panel ones as they give a greater proportion of radiant heat - we all have our preferences.

Like I say, I do have my own UFH heating system and it has its good and its bad points and that's what I tell customers - it suits some people and it suits some houses and suitability depends on people's needs. Speaking for myself, I'm not pushing it like crazy because, had I wanted to make a lot of money, I'd not have gone into plumbing at all - more likely advertising or the police force. I got into this industry because it was something I enjoyed, something that used my skills, and something that is (at times) genuinely useful as a service to society.

If, like John Cleese, you came here to have an argument, do tell me, because I can argue if you want 🙂

 

[Jerry]

The course was BS or the product is?

From what I could tell, the installation cost is way higher (obviously) but you can get back most of the installation cost from the government (RHI).
But after that, you have a way to cheaply heat your house right?
Nope.
Looks like its the same cost as gas/oil/elec.

 

[Jerry]

Personally I prefer the old single panel ones as they give a greater proportion of radiant heat

pardon? i dont understand. can you explain?

 

[Ric2013]

pardon? i dont understand. can you explain?

The heat from a finned rad is mostly convection with some radiant heat also. Unfinned rads give out less heat by convection. Thus you need bigger rads. The bigger rads give out more radiant heat than the smaller finned rads of the same rated output.

 

[Jerry]

The heat from a finned rad is mostly convection with some radiant heat also. Unfinned rads give out less heat by convection. Thus you need bigger rads. The bigger rads give out more radiant heat than the smaller finned rads of the same rated output.

Thanks for the explanation.
If you like radiant heat from old single panel rads, you must be blasting through hot water!

 

[Ric2013]

Thanks for the explanation.
If you like radiant heat from old single panel rads, you must be blasting through hot water!

Why? You'd still use the same rated output of emitter so flow would be identical.