underfloor electric

nwsurf

Hi folks, never posted before but have been reading threads for a while.
I am looking for advice on the use of underfloor electric heating. I am in

the process of planning the build of a fairly small passive house.
Planning permission is granted and i am currently evaluating different
builders and timberframe suppliers.

My hope had been to use electric underfloor running in conjunction with MHRV as my sole source of space heating.
The house is only 1399sqft. However it was pointed out that this would most likely downgrade my building energy rating. Although i was told its still the sensible thing to do. Does anyone have any experience with this?

In the future i would like to put in a wind turbine as the site consists of five acres and is a minutes walk from the sea in an exposed part of north
sligo. Would this grant me a better BER rating once installed and offset
the poorer rating caused by the underfloor?

thanks for your advice

sinnerboy

Lars is right on both counts . ( I really like that guy ) . ESB use will reflect badly at BER CERT stage . But if you are building one of his houses you will hardly need it .

If you use a wood room stove for winter hot water and winter space heating boost - this will give you the best of both - better BER - with lower CO2 rating *


* watch this space - Carbon Taxes are just around the corner .

CJhaughey

The electric UFH is a good system, yes it might downgrade your BER if you have it listed....
BUT if you get scanhome to run some Qualpex when they are pouring the raft you could also also use a small backboiler to provide UFH.
Think of the electric UFH as a backup and a very convenient way to heat the house when you don't/can't light the fire.

I have a scanhome and both electric and Wet UFH.
I haven't connected the qualpex up to anything yet as the electric is very convenient and we are still deciding what way to heat the water.

It only costs a few hundred for the cables and as I say it doesn't need to be used but you can't retrofit it after the slab is poured.

nwsurf

thanks for that guys. think il go for electric and put down the wet piping
aswell like you have done CJ. i had planned to install a glass fronted wood stove purely for the sight of an open flame in winter. do you have it set up with a basic back boiler sinnerboy?

sinnerboy

I personally don't . I describe the set up I saw here

http://www.mosart.ie/passive-house/out-of-the-blue.html

Mothman

Like CJ, I have Scanhome. One of the older ones and not passive spec. The capital costs of the underfloor cables is very little as were the running costs for the first winter. Installed a woodstove and haven't used the cables or any other heating since. Its a firly open plan house and all rooms open to space with wood stove.

While a back boiler sounds like a good idea, they usually compromise the performance of the fire and can result in poor combustion, performance and as a result build up of soot etc. I'd advise to research this aspect.

The aforementioned wood stove has been replaced by a wood burning range. This has worked a dream providing the hot water, cooking and space heat.

Solar panels provide hot water for rest of year.

I mention the above to demonstrate that I can't see how you need wet pipes in floor if you have the stove and IMO even if you don't have stove. Your heating requirement will be much less than mine.

fishfoodie

I'm interested in this as well, even for a SH house as well .

I hadn't even thought of laying both water & leccie in the slab :eek:

I was thinking I'd lay pipes for water UFH but use a small mixed fuel stove for the first couple of years & then put in a garage with a pellet/fuel store & stove in the garage & hook it up to the UFH once I'd a few quid.

In a passive or near passive structure, is a small pellet stove for UFH & HW for this over-kill ?

Also, is there any risk with putting both in the same slab ?

CJhaughey

No risk at all as long as the cabling and piping is done correctly, pipes and cables tied to re-mesh.
Passive or near passive won't need much heating at all, pellet stove will probably be too much, It will be OK if the majority of heating is used for DHW instead of heating the house.
A small log burner with B/B would probably be cheaper to setup and run.

One thing with the elec UFH is that it is a very convenient way to dry the slab before you lay flooring.

fishfoodie

CJhaughey wrote: »

No risk at all as long as the cabling and piping is done correctly, pipes and cables tied to re-mesh.
Passive or near passive won't need much heating at all, pellet stove will probably be too much, It will be OK if the majority of heating is used for DHW instead of heating the house.
A small log burner with B/B would probably be cheaper to setup and run.

One thing with the elec UFH is that it is a very convenient way to dry the slab before you lay flooring.

Damn you CJH, now I have to break out my planning/budget spreadsheet again :D:D

Thanks Mate, I owe you a pint

L driver

Hello,
Have you guys with electric ufh got a stat in each room or a floor stat or is it controlled by a timer? Has anyone measured their esb consumption or too little to be worried about it?
Thanks

L driver

Mothman,
Is your range like a stanley etc ordinary range, that is in nearly every country house?

Mothman

L driver wrote: »

Mothman,
Is your range like a stanley etc ordinary range, that is in nearly every country house?

Yes and no

Esse wood-fired

I'll let you decide what the answer is.

Specifically designed for wood. Can't burn coal. Briquettes are okay. I have my own woodland so make perfect sense from a sustainable point of view. Ash is cleaned out about every 3 weeks. Worked well last winter and didn't even get through the budgeted wood store. There were a few occasions when the house was a little cooler than we'd like but considering it was the coldest winter in 50 years, I'm happy. We wern't driven to turn on the electric cables.

Speaking of the ufh cables, my house was covered by 2 cables. The whole house is treated as one as far as indoor climate is concerned so little point to have separate cables for each room. I did give my opinion that the wet rooms should have their own cable and I think this may be standard spec now. The usual method of control is just by a timer, but I went for automated control. This cost more than the cables themselves but worked a treat. It measured the floor temp and the outside temp and so if cold outside the ufh cables were turned on sooner to compensate for the extra heat loss.

Extra consumption for the first winter that we used electric ufh, I think was an extra £10-£15 (pre euro days) a month. Night rate electricity was 3p a unit then. This for a 125 sqm house at the time. House is now c180sqm with the upstairs converted.