Electric Underfloor Heating vs Water Underfloor Heating (Gas)
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Electric Underfloor Heating vs Water Underfloor Heating (Gas)

by roylec » Mon Jun 16, 2014 2:18 pm

A couple of questions on electric/dry vs. gas/wet underfloor heating.

We are considering electric underfloor heating under a new tiled floor rather than gas/wet. There are two reasons for this:

(1) We have gas-fired warm air heating (Johnson & Starley), and would have to install a second additional gas boiler to run the floor heating because the current boiler won't cope with running underfloor and filling the hot water tank.

(2) We will have to dig tracks into the screed to lay the pipes.

Clearly there is a significant installation cost, and running a second boiler may negate any savings we might make on running costs over electricity because it will only be used to heat the floors in 3 rooms.

So, I am interested in your real practical experience of the heating ability of electric heating wires under tile.

My friends tell me (in their unskilled wisdom) that electric is only suitable for a small room like a toilet or bathroom, and that it only heats the floor.
However I've stayed in houses in the Alps that have only electric heating and they are warmer than a Homebase masonry bit on plasterboard.

WarmUp tell me that their heating can be used as the sole heating solution as long as insulation is correct, which seems to make sense.

So, what is the reality? With the right insulation, is electric underfloor heating, such as Warmup, capable of making a large room feel warm? If so, what does the right insulation mean (see spec at the end for current)

Is there a big difference between the way a wet system feels over a dry? Someone mentioned that there is a glow with a wet system that simply isn't there with dry.

Notes for any questions that people might ask:

  • We have medical reasons why we have to stick with warm air heating, and 'DIY SOS: The Big Build' are sadly not involved.

  • Room is 6mx4m, flat roof, 3 external walls and 6msq of window.

  • Walls are cavity insulated, but may be re-lined with Celotex and board

  • Windows are double-glazed, UPVC

  • Original ceiling is 100mm wool under flat roof then 2 sheets of 12.5mm plasterboard and skim. An additional celing has been fitted 500mm below that with 100mm celotex, 200mm wool, moisture layer, 1 sheet of 15mm board and skim

  • The floor is concrete screed, and I don't know at the moment if it is insulated, so assuming it's not. (Note I am interested in how to find out!)

  • 60% of floor space will not be covered by cupboards or furniture.

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Joined: Sat Apr 08, 2006 1:15 pm

Re: Electric Underfloor Heating vs Water Underfloor Heating (Gas)

by thedoctor » Mon Jun 23, 2014 8:46 pm

We have an underfloor heating company on the wbsite here https://www.diydoctor.org.uk/projects/un ... eating.htm

I actually used them to supply a 5m x 4m mat system for a kitchen I did in Somerset and it was excellent and (apparently) costs a whole lot less to run than the owners were expection. It took only a day to fit, the tiles went straight on top and it heats the entire room, not just the tiles. I was converted and would not think twice about using it again.

Please let us know both what you decide and how you get on with it. You may be able to help others with similar decisions to make.

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Joined: Wed Oct 22, 2014 12:21 pm

Re: Electric Underfloor Heating vs Water Underfloor Heating (Gas)

by Lenh » Wed Oct 22, 2014 12:28 pm

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