Underfloor heating - anyone installed it?

Page may contain affiliate links. Please see terms for details.

manalishi

Active Member
Joined
Jul 5, 2007
Messages
608
Am having an extension added to a 1930s house - kitchen/diner to be about 4m x 7m. The extension will be to modern insulation levels (whereas the house is single-glazed and non-cavity), so should be simple to keep toasty.

Now, the rest of the house has bog-standard GCH, but I'm thinking of underfloor heating for this - to get the even spread of heat and no problems of fitting furniture around radiators (important for a kitchen).

That's the plan, but I don't have a clue about whether it's best to get a wet system and add it on to my existing GCH (assuming the boiler is beefy enough - maybe not?), or an electric system that's simpler and cheaper to install.

Anyone got either (both?!) type and got an opinion?

TIA
 
Had an electric system fitted in a previous house as installation costs were much less.

However, the wet systems are meant to be far cheaper to run and more reliable.

If you're planning on staying in the house for a bit and can afford the up front cost I would go for a wet system.
 
Last edited:
Freidns of mine had electric underfloor heating installd in their 1930's house's Kitchen and hallway and they got the shock of their lives when the leccy bill came in! I think the leccy one is expensive to run.
 
Go wet. We have it in our kitchen ( 565sq feet ). It's brilliant. Runs on the thermostat. We actually use less fuel now than we did before the extension was completed and yet the room is always 70 degs.

But...buy a thermometer. You will need the thermometer to convince the family that whereas they say they are cold one minute and hot the next, actually the room has not changed temp. I say " put a jumper on" or " take your jumper off" depending on what they have just said to me regarding the temperature.

Edit: We just added it to our existing boiler...with no problems.
 
electric is usually expensive to run and pretty much redundant when the stips burn out after a couple of years... like has been said the only proper way to do it is to tie it in with central heating system.
 
Thanks all. Seems the electric stuff runs at about 150-200W/m^2, and that you generally cover 90% of the floor area, so allowing for wall thickness and stuff, I get to about 4.5kW. But there's also a 'warm-up' time and then a 'maintain temp' period of lower consumption). I'll grab up my bill and see what a worst-case scenario is in real money.

crammy69 - I'll bet the hallway is their problem? My hallway (wood floors, gaps, etc) is very leaky.

Go wet. We have it in our kitchen ( 565sq feet ). It's brilliant. Runs on the thermostat. We actually use less fuel now than we did before the extension was completed and yet the room is always 70 degs.

Thanks - 565sqft? For a kitchen? :eek: Makes me feel like a pauper! ;) I'll also see what sort of wet UFH energy costs are likely to be. Hope they're not rated in therms or something unfathomable...
 
My dad has UF electric heating in his flat ( lounge and kitchen ) , directly underneath is the car park ( beneath a concrete floor ) ... the heated bit is probably 350 Sq/ft.

When it was laid , they put a layer of dense foam insulation ( approx 6mm ) , then a layer of thick foil , then the elements , then HD fibreboard , then the underlay and carpet back on top.

Works a treat , bills aren't huge , has been installed for 6 years now , no sign of anything burning out, it is controlled from a normal room thermostat.

The secret is to insulate well so the heat isn't lost into the floor , and buy decent quality kit.
 
We have just finished an identical project to yours - we went with wet heating. I learned:

Check the insulation your builder is planning to put under the screed. There are some high-tech products on the market, but they will probably use a poor-performing cheap one that will mean you heat your concrete slab as much as your room.

Don't install the pipes under where your units will go (especially under the fridge1).

The key is the control system you use. I have simple thermostats but plan to upgrade to stats from Digital Programmable Thermostat Products from Heatmiser. You need sophisticated stats because your floor cannot react quickly to temperature changes and you need a stat with an automatic time offset. You also need a stat with both room and floor sensing for complete control (heatmiser stats cover both these keypoints).
 
Thanks - done some more digging and it seems the use of the right insulating/reflecting stuff underneath it is vital. The current GCH controller is an old and dumb one, so a smarter one would be a good idea.

As it's a new build part of the house, I'm hoping that a wet UFH system wouldn't be as expensive as it would be to retrofit to an existing room... (fingers crossed)
 
Have you looked at geotherm? May not make sense just for the extension though.
 
Have you looked at geotherm? May not make sense just for the extension though.

Or air source heat pump? These will also cool in the summer.
 
Last edited:
I have just completed a large extension for a customer and we fitted Upnor wet underfloor heating and they are very pleased with it. it sits on top of 150mm of celatex insulation and is covered by a 75mm screed. You need to ensure that the screed is fully cured before the heating is turned on and that any tiles are fitted with the correct tile cement.

It was the first wet system I have fitted and it was very easy to install and commision.

HarleyMan
 
Darrell,

I am a builder/project manager and electrical engineer, but I also do all the plumbing for anything we build

Harley man
 
Hi, I fitted underfloor heating in my Kitchen earlier in the year. It was very easy it install, used the insulation boards as described above. I bought a complete kit with boards from an ebay seller included a digital thermostat, paste for boards etc.

It works very well, heats up a lot faster than I thought it would and my cats spend a lot of time laying on the tiles now as they are warm!!!!

Don't think the running costs are high, I've checked my last quarterly bill over the previous year at it was comparable(Although I did get rid of a tumble dryer when I did the kitchen)

Edit: - Electric Underfloor Heating
 
Last edited:
Excellent link - plenty to read up on there. Seems to be about £1200 on the materials for my system, plus the cost of a plumber to run pipes from the existing GCH. Not as scary as i thought it might be...

rees A - I'll browse ebay for more info on them. Do you remember the cost and area you covered?
 
Yes the area covered was only small, approx 6 metres sq. I laid the heat boards(fixed with
tile cement, rollered some adhesive that was included onto that, then laid the heat mats onto that, I channelled out a small grove for the underfloor heat sensor and installed the digital thermostat. The whole process to a few hours.

I then tiled over the top with tile cement that was recommended for underfloor heating(Got it from screwfix so was quite reasonable, the stuff you mix yourself, also bought a mixer thing that attached to drill so made it easy)

I bought from -

eBay UK Shop - the underfloor heating store:

Its a proper store, they have a website that gives details and info. Just had a quick look and they have up to 24 m2 of 150 at the mo but I guess they could do bigger if required(I think I got the 150w p/m version)
 
Last edited:
Excellent link - plenty to read up on there. Seems to be about £1200 on the materials for my system, plus the cost of a plumber to run pipes from the existing GCH. Not as scary as i thought it might be...

rees A - I'll browse ebay for more info on them. Do you remember the cost and area you covered?

You would be far better advised going with the wet system. It will run at a far cheaper rate than the electric system. Probably less problematic in the future and once installed and running properly the floor will be warm 24/7. This is not to deny or denigrate those advising electric. But for new build or an extension it is the way to go for the same reason that you use GCH for the rest of your house rather than any form of electric heating.

1000 litres of oil cost me £392 on 3rd November. It will run out at the end of January, and as well as heating the UFH in our kitchen will heat the rads in the rest of the house. Total floor area is in the region of 3200 Sq Ft. The kitchen will be at a constant 20Degs C throughout. As they say " you do the math".
 
Last edited:

Users who are viewing this thread

Back
Top Bottom