Stick with rads or continue with UFH?

[sb1202]

Having doubts about UFH over rads. 

Project is an extension/annexe old stone cottage 600mm thick walls with no insulation in walls or floor, difficult to heat. Walls are in the process of being insulated. Existing rad circuit in place. 

The annexe is occasional use and my thinking was to install UFH with the Wunda retrofit system, 3 rooms, hall, & bathroom. 5 zones, with thermostats and probes. Total area 45sqm.

The existing floor is suspended chip on 50mm joists on sand & cement screed (see diagram) No insulation between joists and only 50mm space available

With the wunda retrofit, they've said just to stick the panels down over the existing chipboard and the disadvantage is that te floor height is raised by 25mm, meaning refit skirtings etc. Also, the lack of insulation beneath the chipboard has me thinking this is going to cause problems - e.g. it might need to run hotter, which is not good for an engineered wood floor and will require more to heat. 

Am I better just sticking with the existing rads and insulating the floor with 50mm pir, replacing the chipboard and installing the wood floor? Upgrading the rads. Maybe spend the money on heat recovery?

 

Any advice welcomed

[JohnMo]

Not enough insulation for UFH to be effective - stick with rads

Edited 15 hours ago by JohnMo

[Iceverge]

Mechanical ventilation of some kind is a must. 

 

Then airtighess. 

 

Then insulation. 

 

 

Do these 3 well and heating. Becomes an afterthought. Keep it as simple and efficient as possible. Another vote for rads. 

 

I would avoid tiles on the floor in any case. Horrible, slippery cold things. 

[JohnMo]

27 minutes ago, sb1202 said:

Maybe spend the money on heat recovery

Only do that if you have fixed every draft and been air tested to 3 or better, otherwise that defeats most benefits.

 

If you are reasonably draft free you are better doing dMEV or MEV. Something like Greenwood CV2 or CV3 fans for dMEV and then add self modulating trickle vents. Cost pennies to run, can be bought from eBay super cheap and are just about silent - they only boost when needed and they do that automatically based on humidity. MEV same deal, but you have to run ducts to central unit.

[nod]

1 hour ago, Iceverge said:

Mechanical ventilation of some kind is a must. 

 

Then airtighess. 

 

Then insulation. 

 

 

Do these 3 well and heating. Becomes an afterthought. Keep it as simple and efficient as possible. Another vote for rads. 

 

I would avoid tiles on the floor in any case. Horrible, slippery cold things. 

Tiles are fine with UFH There’s plenty of none slip tiles Though the trend seems to be large format high gloss at the moment 

Wood is ok but extremely prone to marking and damage 

[nod]

A friend has recently used Wunda throughout there cottage Around 80 m2 Simalar scenario to you I’m not sure about the running cost 

But he’s really pleased with it