Is the "In Screed" method the most efficient Underfloor Heating system?

[swimmydeepo]

hang on, yours is a wet system (if I'm not mistake) - which pipes need to b= e buried under the screed and in general wet system are slower (but on the = long term more efficient than electric). My understanding is that maybe the heating time for under-tile systems is f= aster - simply because there is less material between the source and the ar= ea to be heated. If a slab of screed is between the heating cable and the r= oom then of course there is more to wait. Then it remains to assess which s= ystem is the most efficient/economical...that's a completely different matt= er.

as it stands, I have a concrete slab (I've just removed the old screed and = pondering about which electric UFH to adopt (forget about wet UFH in this c= ase it's not an option).

[The Natural Philosopher]

well cheaper anyway.

See you have grasped te basic primnciples already. In screed has high thermal inertia. under tile a lot less.

But that's a separate issue from efficiency which is always the ratio of the insulation downwards to the insulation upwards.. My

well if its just for occasional use the 10mm and the wires will work, but it will always be a lot less efficient than more insulation

[Roger Mills]

Indeed. It all comes down to the intended usage. If it's just a case of giving the bathroom a quick warm, having a bath, and then letting it cool down again, a 10mm slab and wires is fine (although a fan heater would probably be better). However, if you want to maintain reasonable comfort levels throughout most of each day, it will cost an arm and a leg to run compared with a wet system and a decent thickness of insulation.

[swimmydeepo]

another variant to consider....there is an economy 7 system of tariffs offe= red by EDF (and maybe other energy companies) which could cut running costs= of electric UFH dramatically - especially if in screed cables are being us= ed (basically the screed become a storage heater). At a cost of about 5-6p = per kW (night tariff from 1 to 7), compared to a standard tariff of about 1=

3-14p kW that represent great savings and maybe a warm bathroom 24h a day.

This is a serious incentive to use proper insulation and a thick screed...a= nd I've just found out there are conductivity issues with screed too (now i= t starts to becoming interesting:

[polygonum]

D "Celotex and kingspan are polyurethane boards"

I thought both were polyisocyanurate?

[The Natural Philosopher]

Fine distinction really

[Rick Hughes]

On 19/10/2012 20:34, [e-mail] wrote: On 19/10/2012 20:34, [e-mail] wrote:> As I've understood the In Screed method (using 7mm cable) is the preferred UFH system for new buildings - so we can conclude this is the most efficient/economical of the lot? >

absolutely not with 100% without question NOT

The most efficient is pipe-in-screed using low temperature Hot water via a Thermal store