In message , John
Rumm writes
On 14/06/2016 11:04, Tim Lamb wrote:
Underfloor heating.

Insulation thoughts... the existing ground floor has 25mm Jablite topped
with 22mm chip. Recommendation is to over fit 25mm of pre-grooved
insulation and a further set of flooring: chip + Vinyl or engineered
hardwood.

Downside is loss of height in doorways.

What is the real energy loss in heating a relatively uninsulated floor
slab in a roughly square building? For 24 hour occupation, doesn't it
come down to what is lost at the edges?


Firstly are we talking about a solid floor, or suspended - I suspect
the former, but its worth checking since it can make a big difference
in these situations.

Solid.

The next thing to consider is the overall area of the floor - larger
floors are disproportionately more efficient than smaller ones, and the
centre of the floor better than the edges.

Roughly 8mx9m

The actual calculation method required is described in BS EN ISO 13370,
and BS EN ISO 6946 will give you appropriate data to play with for U
values of the soil type etc. (I can't find the BSI link on my local
library page the moment to get the docs - your's may be better)

There is also a BRE doc, number 443 that gives some more info on the
process.

Right. I had a poke around. Installed Silverlight as requested and then
failed to make head or tail of the options offered. There are free
calculators out there but beyond my limited skill to use:-(




--
Tim Lamb