Cost of running electric ufh?

[TheMitchells]

In the parents new wet room (the foundations are being done tomorrow), we shall have a concrete floor over insulation.  As its for elderly folks who feel the cold, I need to make sure the room is warm enough for them.  We only have electric in the bungalow and no central heating (its a warm air system).  So my plan is electric mat UFH, tiling over it, and an electric heated towel rail on a timer to come on in the morning about an hour before they have a shower.

 

I am looking at the following for the UFH.  https://www.theunderfloorheatingstore.com/electric-underfloor-heating/underfloor-heating-loose-cables/warmup-loose-wire-underfloor-heating-kit

the room is 2.7m by 1.8m with units along one wall so am looking at a system to cover about 3.5m2. 

But Dad is worried about the cost of running it.  What can I tell him?  Presumably it only heats when it needs to come up to temperature so it will not be on all the time. 

Any advice welcome! 

 

[ProDave]

Well it quotes a power of 150 watts per square metre.  You say the room is 3.5 square metres so that would be a power of 525 watts.

 

At a typical electricity price of 14.8p per KWh that will cost 7.77 pence per hour that it is on.

 

The rest is guesswork as nobody can tell you what duty cycle it might run at to maintain a particular temperature.

[Temp]

+1

 

Once the room is up to temperature the element won't be on all the time. The power required to maintain that temperature depends on the power lost through the structure and to ventilation. To work that out you need info on the area of walls, floor, roof, windows and the  u-values for each and likely ventilation rates. It can take awhile to do the sums and the accuracy may not be very good.

 

Worse case... If we assume it's fully on (0.525kWH) for 12 hours a day for 6 months of the year that would be about 1000 units a year. At 12p/unit that would be £135 a year roughly.

 

I would fit a decent programmable thermostat that allows you to set a different temperatures at different times of the day/night. Eg have it start warming up an hour before they get up, drop down a degree or two during the day, warm up again in the evening, down again at night. But perhaps that's too complicated for them?

 

 

[PeterW]

48 minutes ago, TheMitchells said:

am looking at the following for the UFH.  https://www.theunderfloorheatingstore.com/electric-underfloor-heating/underfloor-heating-loose-cables/warmup-loose-wire-underfloor-heating-kit

the room is 2.7m by 1.8m with units along one wall so am looking at a system to cover about 3.5m2. 

 

Yikes that’s expensive ..!!!! 

 

200w/Sqm with digital programmable thermostat for less than £70 Here

 

Good guys too - easy to fit and reliable. 

 

 

[TheMitchells]

Thanks, Peter.  A much better price.  And I dont think they would be too upset at an extra £10 a month to heat the floor.  The towel rail would be on for a couple of hours during the day and I have seen this one. https://www.screwfix.com/p/electric-pre-filled-towel-radiator-white-980-x-550mm/3012p#product_additional_details_container

I think it was recommended on a post here but I can't find it now.

 

Edited June 26, 2019 by TheMitchells

[joe90]

I have electric UFH With towel radiator in our en suite, only run it in the winter (but it’s on a timer/stat so will come on in cold weather), timed to come on an hour before rising, an hour before evening shower and an hour before bed to clean our teeth, only on fir a short time and it works well. You can always over ride it if you want.

[TheMitchells]

4 minutes ago, joe90 said:

I have electric UFH With towel radiator in our en suite, only run it in the winter (but it’s on a timer/stat so will come on in cold weather), timed to come on an hour before rising, an hour before evening shower and an hour before bed to clean our teeth, only on fir a short time and it works well. You can always over ride it if you want.

 

I assume you are talking about the towel radiator?  or was it the UFH thats on a timer?

[joe90]

11 hours ago, TheMitchells said:

 

I assume you are talking about the towel radiator?  or was it the UFH thats on a timer?

 

Both, separate timers. The UFH timer also has a stat with a probe  so you can set the room temp and/or the floor temp. The towel radiator just a timer. Beware, the towel radiator had a large element (can’t remember the wattage) and it got scalding hot, I had to change it for a lower wattage, wish I got one with adjustable temp (stop kids or OAPs burning themselves).

[TheMitchells]

3 minutes ago, joe90 said:

 

Both, separate timers. The UFH timber also has a stat with a probe  so you can set the room temp and/or the floor temp. The towel radiator just a timer. Beware, the towel radiator had a large element (can’t remember the wattage) and it got scalding hot, I had to change it fir a lower wattage, wish I got one with adjustable temp (stop kids or OAPs burning themselves).

okay, thats something I shall take into account.

[Bitpipe]

I bought electric UFH mats from eBay at a fraction of the cost of UFHSS  range - I also binned the cheap stats and bought nicer ones. Mats were Warmstar I think... had a full warranty as long as you followed the request to use a multimeter to check resistance while in packaging, unrolled and installed and notify them if it deviated from the specified figure.

 

Also bough the little 3 wire (L N E) alarm box that goes off if there is damage while laying. Once it'a down and has been laytexd over it's harder (but not impossible) to damage. Obv once tiles are on it is bomb proof. 

[Ferdinand]

In your situation I have the electric ufh in the bathroom on a timer, programmed to come on for a couple of hours first thing.

 

For electric only and ease of use, I would put the towel rail on a programmable timer switch such as this concept (not a good precise model .. someone like TLC may have something less expensive).

https://heatmyspace.co.uk/product/push-button-timer-switch/

 

You can then program a fixed period of towel rail for heat at other times on the safe push button, and it switches itself off again.

 

Ours has not needed a stat at all, and seems fine. This is a 2010 regs house roughly.

 

Ferdinand

Edited June 26, 2019 by Ferdinand

[joe90]

Yes my electric UFH mats were Warmstar.

[Nickfromwales]

Check this bad boy out.....link

UFH ( UTH ) and towel rad in one.

[TheMitchells]

and we could link the UFH wires ( https://www.ebay.co.uk/itm/323321925126?ul_noapp=true

and a towel rail to this 'Bad boy'?? Looks impressive.

 

[Nickfromwales]

49 minutes ago, TheMitchells said:

and we could link the UFH wires ( https://www.ebay.co.uk/itm/323321925126?ul_noapp=true

and a towel rail to this 'Bad boy'?? Looks impressive.

 

You can. 

Aforementioned gadget courtesy of @Barney12, spotted when hawking around his place when he was out..........

I tried all his underpants on too. A bit tight at first, but 15 minutes of deep lunges and they freed up no end. Did I get any thanks? No. Nothing. Some people ?

[TheMitchells]

Too Much information!! ?

[Barney12]

15 hours ago, Nickfromwales said:

You can. 

Aforementioned gadget courtesy of @Barney12, spotted when hawking around his place when he was out..........

I tried all his underpants on too. A bit tight at first, but 15 minutes of deep lunges and they freed up no end. Did I get any thanks? No. Nothing. Some people ?

 

 

The Thermotouch dual units are excellent. Dont bother with the WiFi version though, its needs the App which quite frankly is toilet paper. 

 

Thanks to @Nickfromwales I've had to tie bloody knots all all my thongs where he stretched the strings. Flipping neanderthal probably flossed with them too ?

[TheMitchells]

Now this may be a silly question - but when I am ordering the electric mat for the UFH, do I use the actual size of the room or do I deduct the areas that will not have the heating, ie under the cupboard/base units?  And if so, how far from the wall/units should the wires start?

 

[PeterW]

Measure just the heater area and not under the wC pan..!!

 

50mm from the edge is fine. 

[ProDave]

Don't do what I saw once, they bought a mat too big, and rolled up the spare under the bath.