Underfloor Heating – FAQs

UFH Specialists
Since 2004

Yorkshire Based
Family Firm

UFH Service

Specialist UFH
Repairs Service

Which Underfloor Heating is Best, Electric or Water?

Both underfloor heating systems achieve the same thing, 21 degrees is 21 degrees whether you use electric or water. As a rule of thumb warm water underfloor heating systems are cheaper to run over the long term, electric underfloor heating can be cheaper to install but costs more over the longer term. We generally recommend water systems wherever possible due to their more economical nature.

How Much Does Underfloor Heating Cost to Run?

Water underfloor heating systems are typically 20 percent cheaper to run than a traditional radiator system powered by a Gas boiler. Electric underfloor heating systems are cheaper to run than Oil, LPG, and Electric storage heaters for those who are not on the gas network.

What Floor Coverings Can I Have on Top of Underfloor Heating?

You can almost any type of floor covering over underfloor heating, this includes but not limited to: Amtico, Karndean, Marmoleum, Laminate, Engineered Wood, Carpet, Tiles and Stone.

What’s the Maximum Thickness of Floor Covering?

Engineered woods no more than 22mm, Stone and Ceramic tiles have a good thermal transfer and we have installed underfloor heating under 50mm flags to good effect. Carpet and underlays need to have a combined tog value of 2.5T or less (yes, carpets have tog values!)

Do I Need Floor Insulation?

Yes we strongly recommend the use of insulation otherwise you could have a heating system that is very un-economical to run. More insulation is better in this situation where floor heights permit.

What is the Cost of Installing Underfloor Heating?

This one is hard to answer in general, the cost will depend on your project and the ease of installation. Most projects can be completed in one day and others take weeks such as large commercial installations. We look at each job on its own merits and listen to your needs, we can design a system that suits your property, we do not install systems that are not suitable for you or your property.

What’s the Minimum Screed Thickness for Underfloor Heating?

By selecting the correct screed we can go low as 40mm screed. This is the minimum before the screed becomes weak, and the plus side you will save money in material cost and the underfloor heating system will heat up quicker.

How Long Before I can use my Underfloor Heating after Screeding?

It all depends on the type of screed, but some systems can be turned on as soon as 2 days after installation, others can be 7 days longer.

What’s the Drying Time for Floor Screed with Under Floor Heating?

Again this is entirely dependent on the type of screed used.

Which Areas of the UK do you cover?

We cover all of the UK, but most of our work comes from Yorkshire and Lancashire, Midlands, North East and North West.

What Happens if my Water Underfloor Heating Develops a Leak?

Assuming the leak is obvious we can easily locate the damaged section of the pipe and repair it.

Should I Leave my Underfloor Heating on all-day?

We suggest leaving the system ticking over during the day and using the set-back feature on the thermostats overnight to keep the heat in the floor and to not allow the slab to go completely cold. For example, if your day time temperature is 21 degrees Celsius, we suggest allowing the system to cool down to 16 degrees, then in the morning the heating system hasn’t got to do a lot of work to come back up to 21 degrees.

what Brand of Underfloor Heating do you Install?

We mainly supply and install Emmeti underfloor heating systems, but we have also fitted Polyplumb AKA Polypipe and JG Speedfit – we have used Nu-heat underfloor heating, Robbens underfloor heating is another one we use, also products from Underfloorheating1 at Doncaster, rehau – We prefer to useEmmeti but we are happy or quote you using your preferred system – we don’t normally supply and install products from Wickes underfloor heating or b&q underfloor heating, but screwfix do a half decent range.

How Much Screed Is Required Over Underfloor Heating?

This depends on the type of screed – but if its a flowing screed then we can go as low as 40mm – the norm is 50mm and sand & cement screeds about 65-70mm.

How much to install underfloor heating?

This questions is hard to answer – its based on each individual project, and no two jobs are ever the same, what we will do is promise to be as competitive as possible and the only way to find out the cost is to contact us using the form on the right or phone 01274 568 536

How Many KW in 200m² of Underfloor Heating?

To find out simply multiply 70w x m²

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179 thoughts on “Underfloor Heating – FAQs

  1. Hi, I want to move my underfloor heating manifold. We are renovating our kitchen and adding an extension. Where the current manifold is is in the middle of the room it comes up from the floor. I literally want to move it about 60cm – 100m straight across so it can be hidden in the island. Is this possible? How difficult would it be? Any help would be greatly appreciated.

    1. Hi – yes its possible, depends on the size of the pipe, assuming its 16x2mm then it should be a simple process of extending those pipes to reach the new manifold location, along with the flow & return from the boiler and the power supply.

  2. Hi, I’ve got a room thermostat controlling a two port valve feeding a manifold ,can I remove the activator heads permanently.only two heads for a kitchen area

  3. Hi. I have single zone UFH system in my kitchen which has recently developed a problem. When the room thermostat demands heat the boiler starts and very rapidly reaches its operating temperature of 70 deg C and overswings to about 72 deg and cuts out. This doesn’t happen when the normal radiator central heating starts on it’s own, or when the UFH is turned on when the radiators are already on. It felt like a problem with the boiler in that it wasn’t able to regulate the output temperature, however, a British Gas engineer visited and said it was a problem with the UFH rather than the boiler, but they don’t deal with UFH. It’s as if the UFH return flow isn’t enough to stop the output from getting too hot – possible flow restriction??? Any advice would be appreciated – thanks!

    1. Hi – it could be one of those things you mentioned – also faulty “auto bypass valve” – thats if there is one fitted. Check you have the installed firstly, then check the blending valve on the underfloor heating by stripping it down and cleaning & lubricating.

    1. Most screeds will need a suitable coving over the top such as tiles for example, some screeds can be used as a wearing surface as long as they have been installed with that in mind from the outset.

  4. Can you tell me how water hardness might affect underfloor heating?
    We are planning to move to a new property in an area with very hard water in Wiltshire.
    I am concerned that lime-scale precipitation will fur underfloor water pipes.
    Apart from installing a water-softener, can furring be minimised by keeping the water temperature within a certain range?

    1. Hi Mike, This is difficult to answer, if the heating system has been maintained correctly with “inhibitors” then it’s likely to be ok and in good condition. It is situations where no inhibitors have been put into the system from new or repair work in the past.

      My advise would be to have the manifold inspected prior to exchange of contracts, this way then you will know what condition it is in.

      Products like https://www.sentinelprotects.com/uk/products/sentinel-x100-inhibitor and https://www.sentinelprotects.com/uk/products/x700-sanitiser-and-biocide are designed to fight against limescale.

  5. Our electric underfloor heating was installed by professionals under ceramic tiles. My question is; can the wiring be damaged by boisterous jumping by my grandchildren?!

  6. Hi, I need to move my manifold by extending the ufh pipes. 1. Is this possible? 2. If so what is the best fitting to extend the pipes – ie compression etc.

    Thank you

    1. Hello – yes this is possible, we wouldn’t recommend “compression fittings” normally, its better to use specialist connectors such as “uponor quick and easy” joints – or Rehau “everloc” products https://www.rehau.com/download/790502/everloc-parts-list.pdf , both of these require special tools sadly.

      Assuming the compression joists will be accessible then they will be ok to use, they sometimes have a habit of leaking, but as i say if you can access them, then it wont be an issue.

  7. an a manifold in a central downstairs location feed up a floor, ie run 2 zones downstairs and 3 up a floor, really no location for a second manifold upstairs, do you need to do anything special to make this work

    see your answer to a prevois question which makes me think this can be possible

    Hi – Yes no problem, we often install manifolds on lower ground floors andie run feed another floor from the same location.

    1. Hi – yes that’s fine, and no you don’t need anything special to make it work, its no different to running rads upstairs from a boiler on the ground floor.


  8. Hi
    We’ve recently moved into a house with wet underfloor heating throughout and everything works fine except in the kitchen. It never gets warm.

    We have the heating on all day but each room has a programmable thermostat. The kitchen has been set to 25 but has never gone past 17 though it calls for heat on the manifold hence boiler is always on because of the kitchen.

    We’ve just had the thermostat changed in case it was faulty and it’s the same. I’ve had “UFH specialists” found via the manufacturer’s website round but they don’t seem to know. I’ve mentioned that based on what I’ve read online it could be air in the system or an electrical fault but they haven’t done anything except touch bits on the manifold and say all should be working fine plus leave with a call out charge.

    Any idea what the issue might be please and do you cover London area? Thanks

    1. Hello

      It could be one of the following or something else:
      Faulty Actuator
      Stuck pin valve
      Air lock
      faulty wiring
      crossed actuators

      Plus other things.

      Yes we do cover London.

  9. Our 12 year old conservatory is presently 29 degrees Celsius but the manual thermostat is still not switching itself off. We have electric underfloor heating. Why is this happening

    1. Its most likley because the relay in the rear of the thermostat has stuck on, despite the controller saying its not heating up. Its done well to keep going for 12 years!

    1. Hello, the industry norm is 2.5T of less combined underlay and carpet. The lower the tog the better it is.

  10. Hi there – I am putting wet underfloor heating in to a new space at home and the screed layer it sits in is 60mm deep and I have ordered 22mm thick limestone tiles. My builder was (apparently) expecting 12mm or so tiles and I asked if the extra tile thickness was an issue for underfloor heating. Your FAQ suggests not but thought I would ask you direct.

  11. My under floor heating in the kitchen gets warm at times but the room stat is turned off & the heating programmer is also switch off.This is in a new apartment & is a wet system.What could the problem be.

    1. Hello – it could be a number of things, without been onsite or knowing more information i cant advise.

      Just one little tip – check the actuators are tight on.

  12. Hi we are going away for four months Nov/Feb because these are the coldest months in the UK my question is should we leave our underfloor heating on over this period whilst we are away ? Also is it safe to do so ?

    1. Hi we are going away for four months Nov/Feb because these are the coldest months in the UK my question is should we leave our underfloor heating on over this period whilst we are away ? Also is it safe to do so ?

  13. I have bought a flat with gas underfloor heating. I am changing the floors though as the ones in the flat are cheap looking and not nice. Do I have to change the whole system as well or is it safe to change the flooring only?

    1. Hello, it should be safe to change the flooring only – but you will need to give the flooring special consideration and the heating system set up: for example if your swapping from a wooden flooirng in the lounge to carpet, you need to make sure the carpet and underlay combinded are 2.5tog or less to be effective.

      Or if your swapping from carpet to wooden floors then make sure the underfloor heating cannot overheat the wood, and be careful putting rugs on top.

      Theres a few things to consider.

  14. Can i combine two seperate brands?
    For example, can I combine a Klima underfloor heating matt, with a Blyss sensor and thermostat?

    1. Hi – firstly i would check with the suppliers – but in my exeperience i dont see why not as long as the thermostat is rated to suit the heating mat.

  15. Hi,
    We are wondering about mixing wet and electrical underfloor heating. Putting wet underfloor in bedrooms, reception rooms and hall and electrical in the bathroom and kitchen due to its quicker turn on time. Do people mix both types of underfloor heating if installing at the same time?

    1. Hi, yes people do, our exeperience is wet UFH to full ground floor and electrical UFH to upper floor bathrooms for example.

      But if your install a full house of wet UFH it makes sense to use the same all the way through.

      Most systems these days are reponsive and lag times have greatly reduced when used with liquid screed or over-lay type systems.

      Hope this helps.

  16. Hi should I turn our underfloor heating off completely in summer or leave thermostats left on low as in the winter?

    1. Hello – leave the thermostats on low as in winter. In my experience thermostats dont like having the power cut to them for the summer – its best to leave them “live” if you will on a low setting.


    1. Hi – Yes it can, its not different to fixing any other pipe in the home, this can be done with compression connectors or other items like Rehau “evalock” and Uponor Q&E (Quick and Easy)

  17. Hi
    We have just had underfloor heating fitted and put the heating on for the first time. Stat put on at 21 degrees and been on all day and only gone up to 17 and floor does not feel warm underfoot? Is this normal, I was under the impression it would feel warm underfoot.

  18. We had just had a liquid screed poured over our wet system underfloor heating pipes. It was supposed to be 50mm screed covering 30mm over top of pipes but now discovered the screed is only 35 – 45mm thick, the average being 40mm. Not sure what to do ???

    1. without knowing the exact product etc, avg of 40mm is normally fine for liquid screed.

      what did the installer say when you raises your concern?

    1. Sure you can – just be careful when choosing what flooring your having, for example carpet and underlay need a combined tog value of 2.5tog or less for underfloor heating.

  19. What size boiler is required for an underfloor heating installation of 200m2. The property is built in 2009 and is well insulated. All windows are double glazed.
    The ground floor if concrete and the upper floor suspended with pipes on plywood and sand screed. The floor covering is carpet.
    Thanks CH

    1. Hello – sorry we cant help on this one, you need to ask the heating engineer who is doing the job for you to carry out their own calculations.

  20. Designing a self build – our architect has designed a heating room in integral garage for manifold & pipe work etc – presumably we should insulate this and pipes to maximise efficiency of system? Any suggestions?

  21. Turning on underfloor heating for first time screed has had 6 months to dry
    What temperature should I start at and when am I able to turn it up day by day or week by week

  22. Manifold positioned centrally in House. Can I have the boiler located in integral garage which is approx. 10m away?

    Also can the boiler deliver to both a downstairs UFH system and an upstairs conventional radiator system?

    Finally can the boiler be a combo boiler?

    Thanks for any help you can give.

    1. Hi – Yes no problem, make sure the flow and return supply pipework is sized correctly.

      Yes by using 2 port motorised valves to “zone” the system – ask the heating engineer to plumb the system as “s-plan plus”

      Yes it can a combi.

  23. What thickness do I need to allow for for electric underfloor heating insulation + mat+ scream+ tiles ??? On top of timber floor

    1. Hello – using a 10mm tile backer board, screwed to timber sub-floor and latex compound on top we would allow approx 16mm – then if you use a 10mm tile and 5mm adhesive your overall build up would be 31mm give or take a few mm’s

  24. Hello, I am wondering what the best practice is for the on-going maintenance of underfloor heating in a commercial residential environment (large care home) – is it advisable to service the manifolds annually?

    1. Hi Robin,

      Happy new year.

      Yes defiantly – we suggest an initial inspection – put right any faults – then take out an ongoing maintenance contract for an annual inspection.

      Every year underfloor heating will throw different little issues and its worth keeping on top of these to prevent the problem getting worse.

      Below is a list we would check during an inspection.

      • Check manifolds for valve operation
      • Check the Actuators for correct operation
      • Check the circulating pumps for operation
      • Check flow rates (this is hard without more information)
      • Check Flow Temps via Thermal Imaging
      • Check the Mixer Valves for correct operation
      • Flush/Bleed underfloor heating pipework if required.
      • Test all the electrical system and confirm the thermostats are working
      • Fault find any electrical items that may not be working and correct.
      • Check the operation of any motorised valves
      • Check the boiler is engaging as and when it should be required
      • Fix and replace any items I can there and then (if I have the parts on the van)
      • Check anything else I can see that may need attention
      • Carry out Thermal Imaging Report to confirm pipe operation
      • This is not all the things we can do – but pretty much covers it.

  25. my husband is in intensive care in hospital and my son is trying to work out how to turn the uderfloor heating on. we only have underfloor heating in the conservatory and only have it on at christms and new year.Could you help me please?

  26. I already have underfloor heating fitted in some rooms of the house and I am looking at possible getting it throughout the whole house now.

    Can you advise if I was to tak up the exisitng tiles will this damage the underfloor heating that is currently laid?


    1. Hello – Its a little vague to be able to answer this right now: Can you tell me what type of underfloor heating it is? electric? or water?

  27. Once a manifold has been installed, can this be moved? Also, can the underfloor heating pipes travel down and then up like normal copper pipes? As in, could they come out the manifold, drop 6 inches, then travel up to the level the heating would be?

    1. Hi – Yes no problem, we often install manifolds on lower ground floors and feed another floor from the same location.

  28. Hi
    We are converting a double garage into living accommodation. The garage has already got a room above with wet underfloor heating, we are wanting to cut a hole in the floor to bring a staircase from the garage below to the room above. Therefore the pipes have to be cut, can they be rejoined again so that the system can carry on working?.

    1. Hi – Yes not problem, but it would be best to use specialist repair connectors such as Rehau everlock, or uponor Q&E rather than the standard compression joints.

      We can help if you need us to.

  29. Can underfloor heating be used successfully with Yorkshire flags? Is so, what is the recommended maximum thickness?

  30. Heating will not activate automatically only on manual. After 15 minutes it trips out. Switch off power and manually reactivate after 30 minutes again will trip out after 15 minutes.

    1. Hi – whilst not exactly the thing to do – i cant see why not, the second stat will be reading the temp of the first floor so therefore wont actually know what the floor it is controlling will be doing, try and install its own probe for best use.

  31. Hi

    Just started house renovation project. Kitchen extension ready for solid concrete floor and want to lay ufh pipework before screeding etc. As yet have not purchased manifold system as plan to add floor upstairs and then finish the ufh in one go but this will be in a couple of years. The question is can I screed downstairs without connecting to anything. I can pressure test the system with air or water to check for leaks and can leave it pressurised before and after screeding. Assuming I can do this is air or water best?


  32. Any ideas why my underfloor heating will also start my central heating ? This didn’t use to happen and were completky seperate.

    Many thanks


  33. My UFH system is separate to my radiators, however when the UFH is on and the radiators are off, the radiators still get warm to the touch.

    What could be the cause ?

  34. My mother’s Polypipe underfloor heating is tripping the RCD; where should I start to look for the problem – which device is most likely to be faulty ?

  35. Hi we have underfloor water heating which has been laid in what was previously a second bathroom but is now used as a dressing room so all sanitary wear has been removed, water heating system installed and ceramic tiles laid.

    We are now reinstating this room as a bathroom but, after removing a few tiles have located the original soil waste pipe however the installer of the heating system has laid the pipe work so that part of it just covers the soil waste pipe. Is it possible to move the pipes by a couple of centimetres so that we can use the original soil pipe to avoid relocating it elsewhere and having to remove tiles etc?

    Thank you

    1. Hi, without seeing it its hard to advise fully, but i dont see why not, as long as moving the pipe wont interfere with anything else.

  36. I have u/f inunder a 60mm screed. The ground floor area is large ,open plan. The living area will have 20mm engineered board glued down. The tiles for the kitchen are 10mm. This leaves 10mm for the adhesive under the tiles. So there will be a height difference between the two areas. What can I do to raise the kitchen floor area so that the floor runs through flush between the living and kitchen areas

  37. Hi we have had a big extension on the back of are house, and had ufh put down. 75mm of celtex between joists and screed mix 25mm, then 22mm chipboard put down, the system has been pressure checked and the glass levels on manifold all sit nicely where they should, and it warms up good in the house, but I have seen some condensation on the chipboard floor in some places, so it’s stopping me laying my wood flooring any ideas what could be causing the condensation on the floor.
    Many thanks

    1. Hi Mike – my only guess is the 22mm chip was laid too soon, and the 25mm biscuit mix wasnt allowed enough time to cure. Even though its not mixed with water there is a good amount of moisture in the sand. Other than that i dont see a reason for condensation.

  38. I have a combo boiler, radiators throughout bungalow and underfloor wet heating in kitchen/ conservatory. Lately when underfloor kicks in, the boiler trips with flashing lights which indicate overheating. Boiler has been checked and seems to be ok. Engineer won’t touch underfloor. Any ideas??

    1. Hi – Its hard to say without been there, but it would suggest something to do with the flow from the boiler through the UFH system. Again similar to other posters on here it could be a bypass issue either malfunctioned or not on the system, it could be blocked mixer valve, faulty pump and the list go’s on.

  39. Is it necessary to use a pir insulation beneath wet ufh that is specifically for ufh like celotex ff4000 or is a general board like ga4000 ok? I’m limited on headroom so need 70mm (the min according to celotex calculator) but the min order for the ff board is 600sq m. Our floor area is 65sq m and we hope to lay 100mm concrete on top to be polished.

  40. Thanks, the builder put in the insulation but never taped the joins and didn’t put any vapour barrier beneath the pug mix. I will check boiler temp, but water temp at inflow to manifold gets to about 45 degrees with 4 of 5 zones on, up to 55 if 1 or 2 zones on. All actuators open when called son don’t think it’s the electrical or mechanical side of things. Am wondering now if it’s down to either insulation not being done right, or whether designed pipe layout was.never going to be able to produce the temp we need. With a pug mic what would you think a max a rain able temp should be for wet UFH. We’ve been in houses with it before that felt really warm, probably 23 or 24 degrees. Many thanks for your thoughts.

    1. We have done loads of pug mix and not yet had one not produce the required results.

      You cant go wrong with the insulation to be honest, taping the joints and vapor barrier are not going to help the situation so don’t dwell on that.

      Its more likely a flow issue – i cant advise further without seeing the set up – without sounding like a idiot its not down to you to sort it out and get your installers back to deal with it, this is basic stuff for any underfloor heating firm.

      If you get stuck you know you can call us out.

  41. Hi there, we have had a wet UFH system fitted downstairs during our house renovation. All subfloors were lifted, 75mm of insulation put between the joists, then the pipes clipped into the insulation and then a dry pug screed mix laid over (to thickness of between 20 and 25mm) probably. The new subfloor is 22mm tongue and groove chipboard. It has been running for a few weeks now, and no single room reaches over 19.5 degrees, even if we run the system for 12 hours straight, which can’t be economical. Any thoughts on why we can’t achieve any more heat, and should we be expecting the system to perform better than this? Many thanks.

    1. Hi – apart from going back to your installers i would check: the water temperature in the pipework, make sure the boiler is outputting 60d-70d water, go to the manifold and check the blending valve (aka mixer valve) and turn it up, it needs to around 50d for this type of installation.

      Ive based this on some assumptions that the control wiring is working ok, pumps are ok, two ports are ok.

  42. Hi,
    I am getting some underfloor heating installed in a fairly large kitchen / conservatory / dining room area.

    I want to be able to manually switch each of the 3 areas on or off. I know there is a central single controller thermostat, but in the winter when the conservatory isnt being used id rather its just not turned on.

    From what i have read it can be done with multiple zones and thermostats, but can it just be done with a manual switch disabling that part of the circuit?


    1. The short answer is yes it can – ask your installers how its done – failing that come to us for a price and we will sort it out for you.

  43. Our wet underfloor heating for a new en-suite has been installed with insulation under the heating pipes, then18mm ply laid over them and screed over with concrete prior to laying the floor tiles. Is this the correct way to install this type of heating? It is very slow in reacting and takes a couple of hours before the floor starts to feel aired.

  44. I’m thinking of installing wet underfloor heating in a house (1990 build) I am buying. I am thinking of only doing “downstairs” (approx 40 sq m), and using a system that “removes and re-lay” the floor scree, with the installation of the WUH in the new scree. How long after the scree is laid can a laminate floor be installed?
    I have also been advised to replace/upgrade the 15 year old oil boiler, all upstairs radiators, “review” the hot tank, power flush the system and then “install” inhibitor upon commissioning (and then every 3 years) – is this the suitable advice?
    Any other comments would also be useful

    1. Hi Pete

      Can you tell me in a little more detail your thoughts – it was hard to read but i think you asked about digging up the old screed and relaying a new one with UFH pipes – is this correct?

      Power flush is prudent prior to fitting a new radiator, its a bit like putting on clean clothes after playing football – its not done, you would have a shower and get cleaned up before putting on clean clothes, same thing with the heating system, give it clean then fit the shiny new boiler – protect the heating system with inhibitor just like you would a car with antifreeze.

      1. Russadmin,

        yes – you are correct – dig up old screed, install new UFH pipes,and then re-screed. Leave to “dry out”, then fit laminate floor.

        OK – thanks about your comments for the order of doing things… power flush, replace parts (radiators, boiler, tanks), refill including inhibitor.

        Any more comments would be very useful



        1. OK –

          Regards to the screed – we use Liquid Screed and under normal conditions these take 1mm per day to dry out upto 40mm then .05mm per day thicker than 40mm. One benefit is the UFH can be used to force dry the screed after 7 days – the key question is when will the screed be dry enough for laminate flooring? – this cant be answered without moisture testing the screed which will be the floor fitters job. For more info on screeds click here Gyvlon but from experience it can be 4-5 weeks if the heating is turned on after 7 days.

  45. I am having problems understand why my plumbed under floor heating is coming on in rooms where the room thermostat is down to zero and yet not coming on a some other rooms where the thermostat is set to low? I have a Veltamat 3D system. Can anyone help?

    1. Hi – early velta systems that have the red actuators on top are prone to malfunction – i suspect this would be the issue, secondly if you have the wireless thermostats they can also cause a few problems.

      Happy to come to and look and i am sending you an email about our services.

  46. We have installed underfloor heating which we have turned on for the first time, it’s been on continuous for 2 days and the highest it has reached is 15 floor temperature. It dips in the morning 11 then goes back up. Why is this when it is on continuous and how long will it take to reach 20?

    It is in the conservatory and it is on concrete, base, heating Matt then levelling compound and tiles.

    My help advice would greaffuuly be received

    Kind regards


    1. Hi – Its most likely the heat mat is not connected to the thermostat correctly, double check the connections. The temp you are seeing is the ambient floor temp.

  47. Hi, I am buying a new build property with under floor heating. A leak has accured in one room. The, builder has gunned out the wet patch completely to include 4 of the pipes. To now correct will require to make 8 joins before re screeding, Is this the correct procedure, or should the whole floor be lifted and all the pipe work replaced? The new build house is not yet completed.

  48. Hi would using metal duck tape to secure the heating cable to the floor effect the under floor heating system I did this and when I switched the unit on the consumer unit tripped just wondered if the silver tape could be the cause

    1. Hi – i doubt it – no – tripping RCD could be many things, but re-check all the electrical connections. The heating cable can be insulation tested at 500V to double check its ok by the electrician.

    1. Hi – This has been done in the past – it will depend on whats under the stone flags to determine how big a job it will be. Happy to help if you send us an email.

  49. Hello, I own a top floor 2 bed/bath 2 living rooms flat under renovation I’m taking up the timber floor to install sound proofing and thought about electric floor heating. Would you be interested in quoting my post code is De722HL
    Thank you

  50. Hi. quick query, iv recently installed a new baxi platinum 33 combi boiler. The customer has a 9 circuit ufh system with individual manifold pump usual setup Inc mixing valve between 40 and 60, and 2 towel radiators that are not piped yet..

    All electrics are installed and all wireless stats.. My question is if the boilers minimum running temp for CH is 25 degrees… Will that then be the lowest temperature the underfloor will run at set by the stats??

    1. Hi, yes -the flow temp is set by the boiler and the mixer valve on the manifold. If you feed the manifold with 25d water and this is lower than the mixer valves setting then that would be the temp.

  51. After having considerable problems from Day one with our underfloor system,most errors have been corrected but when we turn a thermostat on asking for heat the boiler reacts and the flame indicator lights up, after a few minutes the light goes out and this happens on a regular cycle although the thermostat light remains on .Is this normal operation or a fault,

    1. Sounds like the high limit thermostat in the boiler is turning it off – then when it cools down it will fire again – this is caused becuase the boiler is producing more heat than the UFH manifold can cope with.

      It sounds like the boiler/heating system needs a automatic bypass valve installing. Sometimes boilers have these fitted as standard some dont. Automatic bypass valves allow the boiler to continue heating by automatically passing hot water to the return pipe when it has nowhere else to go.

      I would check that first.

      For more information http://www.draytoncontrols.co.uk/AutobypassValve.aspx

      1. Thanks for the rapid response,somewhere in the back of my mind I think we had a bypass valve fitted but will get our heating engineer to check it out,he has consulted Uponor over the other problems and resolved them but this seems to have developed since a new control box was fitted 2 days ago,prior to that the heating was working without cycling but we had to manage the system manually because the boiler was switching on intermittently even when no call being made,this turned out to be a wiring fault,I am quickly now becoming desperate as this system has not worked properly since we moved into this new property 3 years ago

        1. Sorry to hear about all the problems your experiencing – its practically impossible for me to diagnose without actually seeing the install – from your description it sounds like a bypass type issue – but without knowing all the facts i cant say for sure. Best get the guys back to take another look. Otherwise you can book an appointment via and we will take a look.

          1. Thanks again will certainly be having the heating guy back,to be fair to him he has come into this via NHBC after several “experts” have messed about with the system and he does appear to be very experienced,so fingers crossed

        2. Sorry to bother you again but we have just completed a room by room field test and it appears that the stat closest to the Manifold and boiler is behaving correctly where it’s the 2 more remote stats which appear to cause the problem,any clues now ?

          1. Hi – It does sound like those additional thermostats not working – im very sorry but without seeing the installation im powerless to do anything. Try to get the installer back and let them sort this out for you. We can still help but not over the internet – needs to be in person.

  52. Hi, could you tell me what size pipe to use when installing warm water under floor heating in a wet room on first floor ie joists. many thanks Jim

  53. Hi
    Just wondering whether hard water limescale build up affects the operation of underfloor heating? We have a 2 year old house with underfloor heating and have not had any problems so far.
    Thank you

    1. Hi – Yes it can cause lots of problems – if the limescale breaks off into tiny particles this can cause blockages, also limescale can prevent valves from working etc. Make sure you have inhibitor in the system to prevent limescale build up.


    1. Hi – this could be any number of things – my suspicion would be the mixer valve, best thing to do would be to strip it down and make sure the mixer float is not seized up. If you live in a hard water area this is where i would start.

  55. I understand that the flow temperature for UFH is 45 degrees. As such I’m trying to set the right temperature. The copper pipe on the manifold seems a lot hotter that that coming from the plastic pipe. My question is this.
    Where should I measure the temperature from, the metal manifold or the plastic pipework as it leaves the manifold.

  56. We have recently moved into a house with electric underfloor heating in the bathroom and kitchen. Both rooms have tiled floors. Is it cheaper to leave the heating on all the time to stop the tiles getting cold and reduce the warm up time? Our bills seem very high!

    1. Hi, it’s hard to say without knowing the exact build up of the floors, but assuming the electric underfloor heating has some insulation underneath then we would suggest using the timer to suit your lifestyle. One common problem is not having the setback temp low enough, for example if the day time temp is 21d and set back temp is 16d then overnight the temp fell to 16d the thermostat would switch on and maintain 16. This in effect is on 24hrs a day. Make sure the off temp is as low as it can go. Hope this helps

    1. Hi – It depends on the type of UFH. If its a water UFH system we install conduit into the slab during the installation, therefore allowing the probe to be inserted at a later date. Electrical UFH the probe sometimes sits in-between the elements.

  57. Just had screed floor laid in conservatory roughly 3.5 x 3.5. How long should this take to dry before underfloor electric heating can be laid with engineered oak flooring over that and would it be the same for tiles?

    1. Hi – It depends on the type of screed and thickness – the standard is 1mm per day – the screed needs to be moisture dry before bonding anything to it. Same for engineered wood or tiles.

  58. If I had underflooring heating downstairs, do I need to have radiators upstairs, too keep upstairs warm? Or would the warmth work it’s way up to upstairs?

    1. Hi – it depends on the construction of the house – SIPS build do not require heating upstairs – but conventional builds will require heating upstairs. Feedback from customers do report the upstairs benefiting from the heating below but not enough on its own.

  59. Hi ….. I am looking to have a heavy stone fireplace built on an area that has underfloor heating pipes underneath .
    The builder has said he will chip out around the pipes , go down further and strengthen with concrete .
    What kind of weight will this take . I reckon my fireplace will weigh 1.8 metric tonnes across an area of 2.6 m.
    Advise gratefully received!

    1. Hi – Its a hard one to answer because we don’t know the full details – but – im assuming because you have enquired on our website you have a liquid screed at roughly 50mm deep – this type of screed can take 254KG/cm² compressive strength which means 1.2Kgs @50mm. Your builder is right to dig down.

  60. Can you tile the floor immediately over water based UFH. The system consists of pipes on insulated board.

    1. Hi Danny,

      We would suggest at least once every two years, from year 5 after installation. Costs vary depending on the manufacturer, size of system and your location in relation to us (how far to travel) please email sales@underfloorheaingservice.co.uk with full details for a quote.

  61. I have a under floor heating in but have mislaid instructions on how to use thermo…can you help as they all seem to be the same when I have look on site

    kinds regards

  62. What is the most cost effective way to run a Worcester Bosch Greenstar 37CDi boiler with a Danfoss TS715 Si time switch; i.e. run the boiler all day and allow the individual room stats to call for heating when required or use timer programme on/off times during the day in combination with the stats?

    1. Subject to heat up times we would suggest 12 hour period out of any 24hrs. I.e have the heating on from the morning through to evening. Let the stats decide what to do during that 12 hour window.

  63. We moved into our new house in November 2014, we have underfloor heating downstairs and rads upstairs, our gas bill came in this month and was high , we have used £409 worth of gas in 3 months , the house is brand new and well insulated we don’t have the rads on upstairs during the day nor the hot water , the underfloor heating ticks over all the time. It doesn’t seem to fire up very often during the day either do I really don’t understand how we have managed to spend so much on gas . Is there anything we can do to try and lower this , other than turning the heating off?? I really don’t understand the programmer instructions either, I’m not stupid but it’s so hard to follow .

    1. Hi, all it takes is one programmer holding the boiler on, turn down all the thermostats and check the boiler and make sure it’s not firing.

      If it’s firing something is holding the boiler on, if it’s not then I would suggest further investigation

  64. I recently had Warmup unferfloor heating installed in my kitchen & bathroom but neither appear to work. I’m not sure what to do to ensure the system is working corectly, also since installation my heating seems to work only on the timer and if I put it on manually it switches itself off adhoc. I’ve asked the builder that installed it to call & go over it with me but I’ve had no response. I’ve read the instructions and as far as I can see both controls have been programmed correctly so what can I do to find out why it’s not coming on? I’m baffled…

    1. Hi – Your better of contacting Warm-up directly as they will be able to help better than us. try warmup.co.uk

  65. Hi there,

    Any help on this will be greatly appreciated

    I am setting up a home gym outside and will most likely be getting underfloor heating.

    My question is what type of material do you recommend goes in between the underfloor heating later and the actual gym matting? Cement? Plye? Obviously I’m thinking of protecting the floor when heavier weights inevitably being used.

    If this is also something you provide as well as underfloor heating please let me know.

    Really appreciate your advice and input on what products you think best.

    1. Hi, it all depends on the floor build up and if your building a new extension for the gym? maybe a few more details on this would be helpful – but assuming your using water UFH then you will need a screed over the pipes and beneath your matting to protect the heating pipes and provide a means to dissipate the heating.

  66. I wonder if you can help me. We have recently moved into a house that is completely heated by water-based underfloor heating. There are no instructions and the people who installed it are no longer available to talk to. I have three control panels – one for upstairs heating, one for downstairs heating and one for the boiler. Do I have to have the boiler timings set the same as the heating? I am not sure if the two work independently. I understand that the boiler also heats the hot water for showers etc., but there’s only two of us in the house so most of the time we don’t need a huge amount of hot water.

    1. Hi, the “boiler timer will be the hot water I guess, this needs timing to suit you, try heating for 1 hour in the morning and 1 hour in the evening before the bathrooms are used. Extend this time until you have enough hot water for your needs or reduce it.
      We can come and test/check your heating system if you need us to and explain the controls to you. Please contact the office on 01274 568536

  67. In very cold weather is it better to keep the night time temperature the same as day time so that it doesn’t cool down at all?

    1. Hi,

      We would suggest a 5d set back, therefore not totally losing the heat from the slab. For example 21d day time, 16d night time.

      And depending on the speed of your system to warm up, we also would suggest running it for 12 hours out of 24, in other-words on in a morning and set back in the evening/overnight.

  68. Hi, I am laying 75mm celotex on150mm concrete slab then underfloor heating. The area is 140m2. in two rooms the screed will be 100mm will that effect performance of underfloor heating? Thankyou

    1. Hi Helen,

      It depends on the type of screed your using – 100mm isn’t ideal, but its not the end of the world. The better solution if using sand and cement screed would be to reduce the thickness to 65-70mm and install thicker insulation to make up the difference. This will improve the performance of the system.

  69. Hi, it sounds like you need an automatic bypass valve installing before the first T on the flow and return heating pipes directly from the boiler. The system is heating up too quick because there isn’t anywhere for the heat to circulate hence the reason why it’s ok when the rads are on.

  70. When I switch underfloor heating on independently from main heating the boiler switches on but goes up to max temperature and then boiler auto cut out kicks in because it is too hot,the temperature the works itself backs down and then it kicks in again and starts all over again. This does not happen if the main central heating is on. I have a speedfit system with Drayton wi fi controls , and engineer has visited and flushed whole system for blockages and checked pump and all working ok, also the pipe from boiler appear warm enough so not sure why the problem is occurring ? Help?

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