I currently have a radiator central heating system, controlled by a Nest with OpenTherm (combi boiler, no zones/valves). I'm now getting an extension built which will be one big room from the new structure and the existing kitchen and dining room. I'd like to install underfloor heating in this new room. As I understand it, the done thing in this scenario is to move the existing radiator circuit onto a zone valve, then have a separate thermostat and zone to control the underfloor heating. However, I quite like the Nest/OpenTherm that puts out a continuous low level of heat through the radiators, and I think I'd have to get rid of it and go back to On/Off relay control of the boiler if I did that? Or, since my existing radiator system is running all the time at 30-40C anyway, can I just run the underfloor heating off that with a pump and blend valve?
Second question is, for the underfloor heating it seems you can either bury it in the screed or have an overlay system. It seems like it's standard to do under the screed for new build and overlay for renovations. I'm going to dig up the kitchen floor, so I can do either. The screed systems take a long time to respond though, compared to the overlay systems, which seems like a significant advantage to overlay to me? What's the downside? Just price?
Second question is, for the underfloor heating it seems you can either bury it in the screed or have an overlay system. It seems like it's standard to do under the screed for new build and overlay for renovations. I'm going to dig up the kitchen floor, so I can do either. The screed systems take a long time to respond though, compared to the overlay systems, which seems like a significant advantage to overlay to me? What's the downside? Just price?
