'Over Floor' heating systems

[Bemak]

I recently came across 'over floor' heating systems which are essentially an underfloor heating system in a 30mm screed - the idea being that the system is much closer to the surface of the floor allowing for quicker response times while generally running at lower temperatures. I spoke to a supplier about it and they said the following which I thought was interesting

 

• "the system achieves a typical operating energy reduction of 50% daily compared to heating the same space using Under Floor Heating".
• "Conservation of energy on a daily basis sets the ground work for affordable heating and sustaining the building, the most significant feature of Over Floor Heating systems is the remarkable increase in comfort created by operating the system using water at body temperature".   

 

All sounds great. I'd be curious to hear of peoples experiences using such a system as I wouldn't be opposed to trying it on a refurb I've started. 

[nod]

I’m fitting this one for a friend 

10 mil screed So even closer 

[Nickfromwales]

 

[Nickfromwales]

That’s one of many threads here   
 

There’s no way it’s going to be 50% cheaper to run…..

[SteamyTea]

14 hours ago, Bemak said:

the system achieves a typical operating energy reduction of 50% daily compared to heating the same space using Under Floor Heating

Extraordinary claims require extraordinary evidence

[Bemak]

On 07/03/2025 at 18:54, Nickfromwales said:

 

 

 

thanks for this!

[arbennett]

We have Wunda 20mm overlay boards on an insulated suspended floor and they work well with our heat pump. Highly doubt it saves 50% energy cost over rads! That said, the general warmth in the house is lovey compared to previous houses we’ve had rads which seem to have uneven heat across the room. 

[JohnMo]

37 minutes ago, arbennett said:

Wunda 20mm overlay boards on an insulated suspended floor and they work well with our heat pump

Out of interest what is over the overlay boards and what is flow temperature?

[arbennett]

38 minutes ago, JohnMo said:

Out of interest what is over the overlay boards and what is flow temperature?

We have quickstep silent walk underlay and 8mm laminate over it. Has a total r value of 0.065. I was really mindful of what we chose as the floor covering. Tiles would have been better but I was concerned about if we ever need to replace them we’d damage the boards unless we put a leveler down first. 
 

Our weather comp heat curve is set to 35oC Flow at -3oC outside, 21oC internal. Heat loss I calculate somewhere around 40w/m2. 

[LiamJones]

I’ve used wunda over floor boards  befofe in a 3 bed semi renovation with no additional energy saving measures. A warm floor was nice, but I don’t know if it saved money, as I never heated it with rads. Energy usage was about £250pm

in 2019. 3 bed semi 70mm cavity blown beads. 
 

for what it’s worth, if I did it again, I’d probably dig the slab out and do it properly with insulation under and UFH embedded in slab, but, there’s no doubt that’s more expensive to do in the first instance. If I couldn’t justify the “proper” way, the wunda board are a good half way house, and I’d prefer them over rads for sure, even if it didn’t save any money.

[LiamJones]

With that said, I’d focus on airtightness first with that place, it was pretty leaky, and 200mm of PIR under the slab wouldn’t help that. I guess the only reason I dug the slab out of this current one I’m doing, was because I upgraded energy efficiency everywhere. 

[Bemak]

thanks for all the replies on this. I've been distracted with demo starting on site. finally! 

 

what are peoples thoughts on UFH for upstairs as well? 

Edited April 29 by Bemak