Temperature for underfloor heating

andyhop

Gradually build the temperature up otherwise the floor may expand too quickly and you can crack your tiles. Your installer should have told you this

Max temperature on a timber floor with tiles is 28 degrees , concrete can go to around 34

hanlings

Hi Golfergirl 28 - I think you should call the DEVI technical helpdesk, they can tell you what temperature is safe with the setup you have and all sorts of other things related to your DEVI heating.
Their phone number is: 01234 320 260 - pick option 2.

DTDfanBoy

It's most probably barely noticeable at the moment as it's summer, your floor temperature is probably already close to 21c, mine is currently 20.2C, so the electric heating mats will only be coming on very occasionally if at all.


I regret installing underfloor heating in our bathroom, when I renovated it I tiled the entire room, I hate cold bathrooms so I installed an oversized radiator with towel rail above along with electric underfloor heating.


Being an oversized radiator the room is kept heated at about 25C in winter, the electric underfloor heating hardly ever kicks in as a consequence.


I'm currently renovating our en-suite, I've saved my self a few hundred £££ by skipping the underfloor heating and simply installing a large radiator and towel rail instead.


HTH

princeofpounds

Eg if you walk into a room with an air temperature of 21 degrees you'd find it comfortable but a floor tile, set on a table in that room for some hours, would be cool to the touch.

Your body is about 36C, so all these temperatures are lower. Typically tiles conduct heat away much more quickly than static air.

This has a lot to do with how we perceive cold, which is often very different to the real temperature and affected by all sorts of things, particularly humidity and conductivity.

It's much harder to hold an ice cube at 0C than it is to take your glove off at 0C, for another example!

sillygoose

Might just be setup wrong. Many electric UFH controllers use an underfloor sensor but also have a room sensor too. If the UFH is just for foot comfort it needs programming to just control on the floor sensor.

If the UFH is being used for general room heating it needs to be set to use the room sensor and just use the floor sensor to keep the floor from getting too hot at any one time.

Sometimes the latter mode is the default, if set like this and the room being generally warm (especially this time of year) the UFH will barely if ever be switched on as the controller will consider the room warm enough and doesn't need heating.

For you intended use you need to go through the settings and make sure its just set for the floor sensor and set a reasonable target, maybe 24 or 25 to see how noticeable it is then. (The floor will be warmed by the ambient room anyway so may not be far off 21C already if its an upstairs room, tiled floors tend to be colder downstairs where the heat can be carried away by the floor slab acting as a heatsink)

golfergirl28

Thanks so much for all the helpful replies and the Devi helpline number.
We do have a tall radiator in there too so we're not totally dependent on the underfloor heating.
I realise 21 degrees is the temp of the tiles and not the room.
I called the installer today and he suggested I turn it up to 27. He also said as its only 400 watts there will be little difference in running costs between running it at 18 degrees and 28 degrees.
Does this sound reasonable?

DTDfanBoy

golfergirl28 wrote: »

Thanks so much for all the helpful replies and the Devi helpline number.
We do have a tall radiator in there too so we're not totally dependent on the underfloor heating.
I realise 21 degrees is the temp of the tiles and not the room.
I called the installer today and he suggested I turn it up to 27. He also said as its only 400 watts there will be little difference in running costs between running it at 18 degrees and 28 degrees.
Does this sound reasonable?

It sounds like a very dangerous assumption to make if you ask me :cool:


The worst possible difference could be as much as 67.2 units per week, or 3504 units per year :eek:


There's far to many variables in the your situation to offer you accurate advice, but the key to the whole thing is energy being pumped into your floor vs energy leaving your floor vs energy leaving the room.


The greater the temperature difference between your floor and the rooms air temperature the faster your floor will lose energy to the room.


So if you have your floor heating set to 27c it's quite possible that it will be running 24/7, especially if it's a large floor area and/or there is a large temperature differential between the floor and room and/or the room itself is losing more energy that is being added to the room.


HTH

browneyedbazzi

I have warmup electric underfloor heating in my bathroom. We set it to 26.5 degrees on the advice of the electrician who installed it. I find that temperature quite nice - the floor is warm but not hot when you step out of the shower/bath.

We also have a heated towel rail to heat the room so the ufh really is just to warm up the floor - we have it programmed to be on and warm for shower time in the morning but off the rest of the day. In terms of the cost, our unit monitors the electricity used and estimates the cost - I think it was 9p per day last time I looked. It's off now for the summer though!

golfergirl28

DTDfanboy, it's a smallish shower room. Surely it wouldn't run 24 hours a day if its on a timer?
The installer says it costs no more than 4 light bulbs to run as it's only 400 watts. Does this sound feasible?

golfergirl28

Apologies for revisiting this thead. Any idea if cost is really only equivalent to the cost of 4 electric bulbs?