Infrared underfloor heating - any good people out there to talk to?

[NMarshall]

Hi all

I am starting a new build, a small house, 100m2 across a single floor,  using a closed-cell SIPS system including for the floor and have very high levels of insulation. 

I am keen to get underfloor heating in but don't want the extra height / machinery of a wet system and in the past have found standard electric UFH to be expensive to run.

I have used infra red panels as wall and ceiling heaters and love them, both for ease of installation and ongoing running costs, lack of maintenance and zero noise.

Having read up on using infra red as an underfloor solution, it seems to be a perfect match for me, but I am yet to talk to anyone who has actually installed or used it.

Is there anyone out there with some 1st hand experience who can share their thoughts?

Thanks

[ProDave]

Any form of direct electric heating produces 1kWh of heat for each 1KWh of electricity consumed.  Anyone claiming their electric heater is more efficient than a different brand might bot be entirely accurate with that claim.

 

IR heating is intended to heat the person rather than the room, and typically used in a cold building like a church to stop the congregation freezing.  Do you really want a cold house?

 

What is wrong with wet under floor heating and an Air Source Heat Pump that will typically give you 3KWh of heat for each 1KWh of electricity consumed?  Mot a magic or false claim, the extra heat comes from the air outside that is is cooling and extracting heat from.  You can easily DIY install a wet system on a suspended floor that adds about 25mm to the floor height.  Just design for that so the finished floor height is where you want it.

[nod]

Sounds expensive to run

[saveasteading]

39 minutes ago, NMarshall said:

underfloor solution, it seems to be a perfect match for me,

It can't possibly be any benefit? Or real even. Can you find this statement/ claim?

 

Ashp are much more efficient than they used to be, and quieter.

 

I can't see what your concern is re the depth of floor. That is a big issue in a refurb but not with a new build.

 

I am not against IR heaters and have specified them often, both from electric elements and from gas fired hot tubes.

As @ProDavesays, they heat the person or first object they hit so have their place for very local heating.

When I am banished to watch rugby in a very cold room then I have an IR for that, also on a patio for summer evenings, hardly used.  But they are electric heaters using a lot of power.

 

We are here to help and learn. I'd like to know more about this product.

 

[Temp]

2 hours ago, ProDave said:

Any form of direct electric heating produces 1kWh of heat for each 1KWh of electricity consumed.  Anyone claiming their electric heater is more efficient than a different brand might bot be entirely accurate with that claim.

 

+1 

 

I've made some complaints to the ASA about people claiming there heaters are better and had them upheld.

 

IR heaters work well in a commercial garage where you want to heat people stood in front of them but they wouldn't be my choice for a house.

 

If I had to use electric I'd use a heat pump and wet UFH as I'm not a fan of air to air.

 

[SteamyTea]

2 hours ago, ProDave said:

heat the person rather than the room

 

1 hour ago, saveasteading said:

heat the person

Really, there is nothing special about a person when to comes to thermodynamics.

 

1 hour ago, saveasteading said:

or first object they hit

That is better.  It is an inverse square law, so double the distance from the heat source, you half the power transfer, why people crowd around a fire.

Then there is the angle each direct beam of IR hits the object, at 30° half the energy goes somewhere else, and then gets worse as the angle increases.

 

There is also the physiology of humans.  We breath in air.  If we breath in cold air, we have to raise the core body temperature by some other method, i.e. moving about.

We also have a relatively small surface area (couple m²), which we then cover in clothing, to stop heat transfer.  Don't believe the claims about Far Infrared, they don't really 'penetrate' the skin much, thankfully.  Microwaves, which are the next longest named range of the electromagnetic spectrum, don't really cook from the 'inside', ask any chef.

 

 

@NMarshall

If I every see, or hear about some novel technology that is based on simple principles, I always ask myself 'why is it not used by everyone'.

[Temp]

2 hours ago, NMarshall said:

don't want the extra height [of wet HFH]

 

What extra height? Floor heating is thick because you need a lot of insulation, I don't think you would need any less with IR heating. 

[saveasteading]

37 minutes ago, SteamyTea said:

There is also the physiology of humans

We used black tubes in the ceilings of sports halls. Gas is combusted at one end and expelled at the other. The tube gets hot and a lot of ' glow' is apparent underneath it. It heats the air of course too but it stays up high.

Sports teachers report back that the pupils moan about being cold in the first class of the day. But they respond to the whoomph of it firing up, then start running about, and the heater can be turned off again for the rest of the day. 

[SteamyTea]

25 minutes ago, saveasteading said:

Sports teachers

They are a peculiar species. Not human at all.

Most seem to dress like Jimmy Savile as well.

 

[scottishjohn]

3 hours ago, ProDave said:

DIY install a wet system on a suspended floor that adds about 25mm to the floor height.

excuse my correction

but it will be more like 40mm by the time you have your heat sink .  (t+g cement board on top of ufh piping) added-then floor finish of your choice 

Edited Friday at 16:18 by scottishjohn

[ProDave]

46 minutes ago, scottishjohn said:

excuse my correction

but it will be more like 40mm by the time you have your heat sink .  (t+g cement board on top of ufh piping) added-then floor finish of your choice 

There are many ways to install UFH.  My preferred method is 25mm battens UFH pipes between and fill with pug mix.  Your finished floor goes over the the top which you would have any way.

 

But it is irrelevant in a new build, you plan for it and design the building according to what method you propose.  Not wanting to add to the floor thickness in a new build is a weak excuse for not fitting UFH.

[ReedRichards]

I don't think infrared underfloor heating makes any sense whatsoever.    If you could bury an IR emitter under the screed then all the IR would surely be absorbed in that screed so there would be no difference to conventional electrical underfloor heating.  Unless you are telling me that can get special screed that is transparent in the infra-red?  And then special IR-transparent carpet or tiles top of on top of that.  Nonsensical.    

[NMarshall]

Thanks for all the input so far. 

 

I am most definitely not bothering with a wet system for such a small house. I have one in my home and personally I am not a huge fan of the air source system. It is not cheap to run, makes a lot of noise, has a lot of maintenance issues. 

 

I have no problem with wet UFH per se, mine is in 60mm of screed and I do know there are some great products put there like Omnie boards which mean that I can reduce build up considerably. 

 

Where I am building I have a lack of talented plumbers and IR is definitely my preferred method. I have used it on walls and ceilings before and there are products out there claiming to work well underfloor. I have visited a small home office with it under tiling and was amazed at how warm the floor was. 

 

Here are some of the products I have been looking at...

 

https://infraredheatinguk.co.uk/products/underfloor-infrared-heating-film?srsltid=AfmBOoqDTYy_k1oyFWbMfDjZfcJSu764oA8NYTRRI_y2Qoi0sz-kb72C

 

https://termofol.co.uk/product/heating-film-complete-kit-140wm2/

 

And some "sponsored" information! 

 

https://www.theecoexperts.co.uk/infrared-heating/infrared-underfloor-heating

[ProDave]

13 minutes ago, NMarshall said:

I am most definitely not bothering with a wet system for such a small house. I have one in my home and personally I am not a huge fan of the air source system. It is not cheap to run, makes a lot of noise, has a lot of maintenance issues. 

 

I have no problem with wet UFH per se, mine is in 60mm of screed and I do know there are some great products put there like Omnie boards which mean that I can reduce build up considerably. 

 

Where I am building I have a lack of talented plumbers and IR is definitely my preferred method. I have used it on walls and ceilings before and there are products out there claiming to work well underfloor. I have visited a small home office with it under tiling and was amazed at how warm the floor was. 

First point, not cheap, noisy and maintenance issues is not typical. What were your problems?

 

Second point, if the floor felt warm to walk on then the IR heating is not performing as IR heating (to warm the person) but is performing as resistance electric floor heating and warming the floor.  Yes that will heat your house but at about 3 times the cost of a heat pump.

 

And if an electric under floor system fails, (which they do) it is an expensive rip the floor up and re lay the heating system repair.

 

Your choice and if you decide to go ahead please let us know how it performs.

[scottishjohn]

3 hours ago, ProDave said:

It is not cheap to run, makes a lot of noise, has a lot of maintenance issues. 

sorry I and lots of others would disagree on  your statements 

as for complicated you can just run a simple one zone system which gets rid of all the expensive controls if the house is so small 

and how much  grant can you get for your preferred system --sod all ,working on your assumption that it is too complicated for you to do a system yourself ,which of course is not really true  , if you are considering self build there areltos of other things just as complixated  inthe build 

[JohnMo]

9 hours ago, NMarshall said:

am keen to get underfloor heating in but don't want the extra height / machinery of a wet system

My floor area is twice yours I have 7 loops of UFH pipe on a manifold. A heat pump outside and not much else. In house is silent as there is nothing going on in the house. The other bits are a diverter valve and a single thermostat.

 

Everything in the floor and manifold cost about £800, thermostat cost £60.

 

IR UFH kits seem to be about £500 for 20m², so our house would be about £5k, instead of £860. Admittedly you need another heat source to drive a wet system. But even without a grant a Panasonic heat pump is about £2.5k. So not far off half the price. 

[Mike]

10 hours ago, NMarshall said:

I am keen to get underfloor heating in but don't want the extra height / machinery of a wet system

A wet system is simple and about as future-proof as you can get. It should last for decades and you connect it to almost any heat source, though an ASHP is the obvious one to go for now.

 

 

[saveasteading]

@NMarshallthanks for the links.

It's difficult to tell if they are lying about the supposed benefits, or simply don't understand it.

Bottom line....it is an electric heater. It would be a nice luxury for bare feet on a tiled bathroom floor.

Otherwise it is expensive to buy, and to run, and will NOT heat people by IR as claimed, as it is within the floor, which warms.

These adverts should be shut down.

 

[ReedRichards]

Quote

Underfloor Infrared Heating Film is a very thin heat producing film that is laid under the floor covering. The film is produced using a printing technique and it works based on an electric resistance of the carbon element.

 

So it's just a type of electrical underfloor heating that works on the resistance of the heating element, just like every other type of electrical underfloor heating.  Unless you put transparent glass tiles on top then infrared has nothing to do with it.    

[joth]

To clarify, are you self building as owner occupier, or building this as a developer or as a build to let? If this is a business venture, I certainly appreciate why you would be biased towards minimum capital cost, least skill and least risk of call back to maintain/repair. But most of us here are owner-occupiers are naturally more interested in long term running cost savings, which can only mean using a heat pump if using electrical heat source.

You consider 100m2 to be such a small house, yet it's at the upper end of the UK average size (estimate of 85-100m2).  ASHP + wet UFH or rads is pretty much de facto  option for new builds now, so the size is not a issue. And of the two UFH is lower maintenance than rads over the lifetime of the house, that's for sure.

Edited Saturday at 07:25 by joth

[SteamyTea]

26 minutes ago, ReedRichards said:

Unless you put transparent glass tiles on top then infrared has nothing to do with it.    

Yes and no.

Energy is transferred because it excites electrons to a higher orbital.  The higher energy electrons want to return to their original, more stable, state, when they do, they emit a photon.

That photon, which can be though of as a packet of pure energy i.e. massless, moves until it interacts with another electron, raising the electrons orbital, and then ceases to be (can be modelled as an 'at rest mass').

So while we like to think of thermal energy transfer as conduction, convection and radiation, it is really all radiation.

It gets a bit more complicated as there is intensity and frequency, and I have never found a simple to understand explanation.

The nearest I can get to, to explain intensity, is that depending on the material i.e. which elements, the strength of the bond between the electron(s) and the nucleus is different, so some materials take more, or less, energy to dislodge an electron i.e. different place on the electromagnetic spectrum.

Then it is the number of photons, the frequency, that pass or change the electrons in the element, that governs the rate of transfer, the power if you like.

There is no decent 'mechanical' description as it is a quantum problem, and as they say, 'if you understand quantum physics, you don't really understand quant physics'.

[Iceverge]

Before we all pile on.....

 

Below a certain annual heat demand the capital cost of the ASHP will never outweigh the higher running costs of direct electric heating. 

 

The last time I checked it was circa 1000kWh for an A2AHP. 

 

An UFH mat may not be such a bad choice for a small building. Especially if it's excellently insulated/airtight/MVHR/3G etc etc. 

 

 

 

[SteamyTea]

3 minutes ago, Iceverge said:

The last time I checked it was circa 1000kWh for an A2AHP. 

I really should check up on this again.

I use less than 1 MWh/year on heating and about 1.6 MWh/year on DHW.  I have never got the numbers to stack up, but it would give more flexibility on when I heat without a large price penalty i.e. difference between day and night rates as I am on E7.

I have never been able to make fitting PV worthwhile, but that is really down to the roof not being large enough, and not facing the best ways.

[Iceverge]

Forgive my formatting. Spreadsheets on my phone isn't my forte. Here are two examples. The first is UFH electric mats and an immersion. The second is an ASHP and UFH with what I think are realistic install and running costs. 

 

 

This first sheet is for 1000kWh/year and 1800kWh of DHW. Say a 100m2 passive house with 2 occupants. 

 

Line #4 is direct electric UFH and an immersion..

 

Line #5 is ASHP.

 

Break even looks about 12-13 years. 

 

 

 

This second sheet is with 6000kWH space heating and 3650kWh DHW. Maybe a good Bregs new build with 2 adults and 2 children. 

 

 

This breaks even much earlier, I guess about 2.5 years. 

 

 

ASHP might make sense eventually in the first example but I reckon it'd have cost more in maintenance or needed to be replaced before it ever got the chance to pay itself back. 

 

Edited Saturday at 08:23 by Iceverge

[Iceverge]

Out of interest, 

 

I've done this with lots of combos.

 

I think A2A and solar PV plus divert is probably the cheapest lifetime install for a building that is well enough insulated not to need central  heating.