Electric UFH - Costs to install?

[kirky1176]

Ok. So I know that cost is a very subjective thing but I'm in the midst of a renovation - my first real project - and we're planning to tile most of our ground floor so to take the cold edge of the tiles, we're planning on installing electric underfloor heating.

We've had a quote for around £4500 for 45m2 which is based on using the WarmUp 200W mats and includes their WiFi thermostat. Due to the size of coverage in a single room, I expect we'll need a Contactor (from what I've read).

Based on my online research, the WarmUp mats are about £435 per 15m2 roll meaning we're looking at around £1300 for the mats. The thermostat is about £105. So taking this in to account, I can't help but feel that this quote is way too high, even if I factor in additional costs for the Contactor, cabling etc.

The questions I have then are:

1. How long would it take to install 45m2 of electric underfloor heating in a single room?
2. As this is is not a primary heat source (we'll have radiators as well) but will only be used as 'tile warming', 200W seems excessive - I've read that 100W or even 150W are ideal for tile warming applications. Any views?

I'm challenging my builder on this cost as it seems high but before I push too hard, it would be great to get some views.

Thanks!

 

[Diver Fred]

Is the price above the total cost (including tiling) or is the £4k5 just the labour for installing just the mat?
I've just 'done' a bathroom (see 'Why Don't I'). The mat looks to be on the higher cost side (the supplier I used charges £280 per 15m2).
Think you need a breakdown of the costs.

Expect 2 men one day to 'level' the floor;
2 men one day to insulate the floor,
2 men up to 3 days to lay the mat and spread the leveling compound or/and tile adhesive.
Could be 2/3 days to tile that area.

The floor will need insulating unless that is already in under the raft floor. Electric U/Floor heating needs careful thought - you have to be careful about furniture etc is placed once in use - you do not want 'hot spots' that can burn the elements out. Think you may also need more than one thermostat. You may be surprised at the amount of materials, other than the mat, used to lay the mat down.
As for square metre-age wattage of mats, higher ratings will warm up quicker.

 

[Taylortwocities]

to take the cold edge of the tiles, we're planning on installing electric underfloor heating.

That is all that electric UFH is going to do.
It would have been better to provide wet underfloor heating, then you'll heat the room and have warm tootsies. Did you consider that?

£4500 does sound a bit rich but its impossible to judge prices from a keyboard. There may be some logistical issues that push the cost up, like where will the power come from for all this? Has he added in money to install premium insulation so that all your electric doesnt just go into heating up the World's crust. etc etc. Also I'm guessing this is a later in the project add-on? If so, he probably doesn't want to do it. He thinks it's a nuisance and he has priced it accordingly.

 

[flameport]

it would be great to get some views.

The running costs will be astronomical.

 

[kirky1176]

Thanks for all of the replies, they're all helpful. To provide some clarity/answers:

• This cost doesn't include any finishing of the floor (tiling etc.), that's been quoted separately
• It doesn't including any remediation work on the floor - it needs to be levelled as we've knocked through a bunch of walls and the levels are a little varied(!) Like I say, this cost is separate.
• Yes, we considered a wet system but we simply couldn't afford the increased height on the floor
• Yes, I know that the operating costs will be high which is why its there to take the 'edge' off what would otherwise be quite a cold floor (and yes, I know I could just wear slippers/thicker socks!) - We will have multiple radiators in the room for general heating.
• This is part of a much wider project which is still very much in full swing and the electrician hasn't even started on the 1st fix yet. We added it in very early in the project once we decided to use tiles on the floor.

 

[Diver Fred]

So is that £3k for labour? 8 days for 2 men?


Thinking about the U/F heating floor thickness...

My floor from top down not counting tiles and adhesive.
Leveling compound 3mm over thickness of mat
Electric mat 7/8mm
Insulation 10mm
Leveling compound 3mm at thinest

If you can install a wet system (I couldn't - no suitable water heating source) the electric mat is about the same thickness as 8mm water pipes. Then you should be able to dispose of the radiators and you will have less problems with hot spots.

 

[kirky1176]

So is that £3k for labour? 8 days for 2 men?

That's what it looks like to me. Even if I assume £500 for other materials (Contactor, multiple thermostats, cabling etc.) they're still suggesting £2500 labour which just sounds like a lot. But it only sounds like a lot as I'm assuming maybe 3 days to install.

My floor from top down not counting tiles and adhesive.
Leveling compound 3mm over thickness of mat
Electric mat 7/8mm
Insulation 10mm
Leveling compound 3mm at thinest

So are you saying that you have about a 20-21mm buildup, not including the tiles/adhesive (which I guess is another 10mm for the tiles and 4/5mm for the adhesive?)

 

[ericmark]

I fitted electric underfloor heating in my mothers wet room with the idea it would dry the floor tiles so prevent her slipping on a wet floor since she only had one leg. It was not the only heating in the room, also had a large towel rail.

The first thing that was done was existing concrete floor was removed all the drains re-done, and a insulated floor replaced it, clearly don't want to heat the ground below the house.

The time for the floor to heat up is around an hour, however the shower cools the floor, so it did not dry that quick, without the towel rail on the room is cold, it is not enough to heat room without towel rail, and since mothers death rarely used, main reason the floor is not really cold, the insulation which was put down first means you can walk bare foot without considering the floor as cold.

So is it worth digging up floor and adding insulation, yes likely it is, once that insulation is fitted is it worth also fitting underfloor heating, no not required once insulation fitted.

Fit underfloor heating without insulation first, well that would be daft.

So cost is mainly down to removing floor and adding insulation, ours was polystyrene blocks about 6" thick covered with plywood which then had heating element and finally tiles, I would say the heating elements were a very small part of the cost. So really you need to ask builders about costs, not electricians as most of the money is spent on building work.