# Underfloor heating and insulation questions



## August (19 Apr 2007)

We are currently at planning stages of our self build.  We are keen to get UFH but don’t know much about it.  We have been recommended by our architect to get UFH downstairs and rads upstairs and basically insulate the hell out of the house!!!  Just wondering if anyone can answer these questions for me.

  At what stage should we start meeting with UFH suppliers?
  What pump works best with UFH?
  What would the average costs be for 126 m2 (2155ft) and how much extra would this be than putting in radiators?
What kind of insulation should we look at?


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## ang1170 (19 Apr 2007)

Couldn't help noticing, but 126 sq. m is about 1356 sq. ft.

On your questions, surely your architect can answer them? Isn't that what they're paid for (amongst other things)?

It can be very hard to get good independent advice (we're going through a similar planning stage at the moment), so I can understand where you're coming from. It seems to be particularly difficult in the areas you mention, as there are a whole load of new players in the market.


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## August (20 Apr 2007)

Thank ang.  The architect we used only drew up the plans.  I will chat to my engineer about it but would like to as you say get independent advice also.  

Best of luck with your build.


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## extopia (20 Apr 2007)

Plenty of threads here here about UFH.

As to what pump works best with UFH, you can choose from the usual gas or oil-fired burners, solid fuel or wood pellet boilers, ground source or air source heat pumps. You'll have to weigh up the pros and cons.

Be careful about the UFH/radiator combination. In an UFH system, the water temperature in the pipes is about 30 degrees Celcius - much lower than conventional radiators. So your upstairs rads will need to be optimised for this. You can get fan-coil radiators which operate with a low temperature supply, but require a small electric fan to help distribute the heat. This complicates your wiring somewhat so your electrician will need to know about it. There are other types of radiator available too.

Ask your architect about these options before you decide on a spec. And think about how you're going to ventilate the house too - conventional "hole in the wall" ventilation is fine for air exchange but maybe not so great from a heat loss point of view. Ditto open fireplances, even if only used for effect.

I have the fan coil rads upstairs and, while they work fine, I hate the fact that they require an electrical input. It just bugs me, as we were aiming to be as "green" as possible.

It's never too early to talk to UFH suppliers. And if you're going with a heat pump, you'll want to apply for the SEI grant as soon as possible (or up to a year before you plan to draw down the grant).

Search the forum here for threads on heat pumps, geothermal and Underfloor heating, you'll get plenty of info.


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## xt40 (21 Apr 2007)

extopia said:


> Plenty of threads here here about UFH.
> 
> "
> Be careful about the UFH/radiator combination. In an UFH system, the water temperature in the pipes is about 30 degrees Celcius - much lower than conventional radiators. So your upstairs rads will need to be optimised for this. You can get fan-coil radiators which operate with a low temperature supply, but require a small electric fan to help distribute the heat. This complicates your wiring somewhat so your electrician will need to know about it. There are other types of radiator available too.
> ...


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## extopia (22 Apr 2007)

I probably should have been more specific - special radiators are needed when you are using a heat pump (ground source or air source) designed to heat the water to the lower temperatures required by UFH. Such pumps cannot boost the temperature up to what would be required by normal radiators, if you choose to install radiators upstairs rather than go with UFH upstairs.


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## galwaytt (23 Apr 2007)

I have ufh downstairs, rads upstairs.  Never again - the rads, I mean.  UFH on both floors in our new build, nearing completion. 

UFH on both floors simplifies circuits and controls too, using as it does, a common water temp.  

My entire plumging system, for a 316 sq m house, ufh on 3 levels (including basement), super-condensing gas boiler and solar panels, was 26k.  This includes all sink/bath/shower plumbing etc too.  Not bad, I thought.

Oh, and No Copper and No Qualpex Allowed. (personal rule  ).  Hep2O  only.

My existing house (finished 1998) has ufh/rads, iirc, ufh was actually less than rads at the time.  No reason if should cost more, anyway -it's actually simpler.


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## ted (23 Apr 2007)

is qualpex that bad


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## galwaytt (23 Apr 2007)

no, to be fair, Qualpex isn't _bad_, but I find Hep2O is much better.    A lot less memory in the pipe, more malleable, so easier/nicer to work with.

Just my 0.02, that's all, Qualpex isn't going to fail or anything.......


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## ted (24 Apr 2007)

Thanks for that. Have a lot of it buried in concrete floors - perish the thought it would fail


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## galwaytt (24 Apr 2007)

sorry, no, not trying to put mockers on Qualpex - I'd put that in before copper - perish the thought !!.

I don't know what the half-life of the plastic is, but I bet it's a lot longer than I'll be on the planet..........


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## Silvergirl (31 May 2007)

Hi Galwaytt,

Can you pls advise on the monthly running costs for your UFH costs?

We were advised on the ufh downstairs and the rads upstairs... are you in your new house yet?

Would be really interested to hear how you are getting on with the ufh throughout the house,

Thanks


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## galwaytt (1 Jun 2007)

My current house has UFH downstairs only, and rads upstairs (currently being re-done, btw........)

Cost per month, for my heating is Eur107.  This allows for all heating, all hot water, and two fires. (one used a lot, one occasionally).  House is conventional build, albeit dry-lined downstairs.  I do not have an immersion or elec showers, so every drop of hot water is included in that price.  House is approx 2200sq ft.

New house, no idea yet - still not in ! but power turned on yesterday, so not too long now, I hope........new house is ufh upstairs and down - wouldn't even consider rads.

I don't know where you are on your build, but I hope you allow for the insulation height etc, in your wall heights/door heights.......


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## inchbyinch (1 Jun 2007)

Galwaytt,

what flooring types (tiles/wood/carpet) are you using in your new build. Interested as you have experience of it and wondering what you are using? I wanna use carpets in some of the rooms but it seems one has to be extremely particular when chosing same.

Ta


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## inchbyinch (1 Jun 2007)

Also what do you mean by insulating heights?


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## reijonen (1 Jun 2007)

I have two insights: plastic piping is faster than laying copper piping; which means that labour costs are lower. There is a palpable trend for plastic to replace copper for other reasons too, not least because there are fewer joints which means fewer pipes bursting. Trust in PEX or plastic-combination pipes. I don't know about radiator costs, but in the long run I suspect that any increased cost of laying ufh will be offset by energy bill savings.

The much, much higher cost of underfloor heating comes in only when doing a refurbishment: to lower the floor of my 72 spm flat in Streatham would have cost at first estimate about £4,500, as it would have involved digging into a concrete floor by 14 cm and relaying the base so as to provide space for the UFH. In a new build this problem does not exist - I would definitely go for UFH.

My comments are based on my experience as a stock analyst following a company that does UFH (www.uponor.fi) that's doing fantastically well. 

My other comment is: why on earth use radiators upstairs?? The only reason could be that you really want to use thick pile carpets there. Otherwise the heat in a house tends to travel upwards, from my experience growing up in a 2-storey house. More than 50% or more new residential building taking place in countries like the Nordics, Switzerland and Germany are including UFH.  Bear in mind that in these countries, double glazing and triple glazing are standard, as are much higher levels of wall insulation: so my guess is you'll have to have double glazing and wall insulation as well as the UFH, to gain the energy savings.


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## Bridieg (2 Jun 2007)

I am in the process of drawing up plans for a self build stick framed home(not sure on style of house yet  (aprox 1500sq ft) has anyone installed a air-water pump and UFH with or without solar any info would be appreciated ie cost,tips,also what is the deal with screed


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## keeper (3 Jun 2007)

Just at first floor level on a 3000 sq. ft ICF self build, would love UFH, but have been put off by running costs of same when using oil or geo-thermal heat pumps. UFH on oil seems to cost a fortune, and having researched UFH via geothermal, lots of horror stories about ESB costs and system configuration. Have ruled out Wood Pellet Burners for reasons of poor pellet supply/product quality. Anyone had experience of UFH via geo thermal, particularly interested in actual running costs of heat pumps.


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## chimpster (3 Jun 2007)

keeper said:


> Just at first floor level on a 3000 sq. ft ICF self build, would love UFH, but have been put off by running costs of same when using oil or geo-thermal heat pumps. UFH on oil seems to cost a fortune, and having researched UFH via geothermal, lots of horror stories about ESB costs and system configuration. Have ruled out Wood Pellet Burners for reasons of poor pellet supply/product quality. Anyone had experience of UFH via geo thermal, particularly interested in actual running costs of heat pumps.



I am running a 30 KW wood pellet boiler to heat just under 3000 sq foot of UFH. Its on 24 x 7 at the minute as I am trying to dry out the house before putting down floors etc. I am using bagged pellets at the minute as I am awaiting an outdoor silo which will allow me go bulk. My DHW is not connected up yet so its only the UFH thats calling the boiler for heat (Solar will take care of DHW alot of the time anyway). 

I am burning less than 1 bag of pellets a day at the moment. Thats 15kg of pellets a day.  Thats 3.50 euro per day at bagged prices and once I go bulk this will drop to 2.50 a day. I am well impressed. A self modulating pellet boiler works very well with UFH.


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## keeper (4 Jun 2007)

chimpster said:


> I am running a 30 KW wood pellet boiler to heat just under 3000 sq foot of UFH. Its on 24 x 7 at the minute as I am trying to dry out the house before putting down floors etc. I am using bagged pellets at the minute as I am awaiting an outdoor silo which will allow me go bulk. My DHW is not connected up yet so its only the UFH thats calling the boiler for heat (Solar will take care of DHW alot of the time anyway).
> 
> I am burning less than 1 bag of pellets a day at the moment. Thats 15kg of pellets a day. Thats 3.50 euro per day at bagged prices and once I go bulk this will drop to 2.50 a day. I am well impressed. A self modulating pellet boiler works very well with UFH.


 
That seems quite economical, the reasons we ruled out wood pellet so far were briefly: lack of guaranteed supply source, variable pellet quality, stories of rodents nesting in pellet storage area, plus space and storage conditions required.  Would consider pellets if I got a some feedback on the above (realise that these have been covered in some previous threads, but it seems to be a developing market)


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## chimpster (4 Jun 2007)

keeper said:


> That seems quite economical, the reasons we ruled out wood pellet so far were briefly: lack of guaranteed supply source, variable pellet quality, stories of rodents nesting in pellet storage area, plus space and storage conditions required.  Would consider pellets if I got a some feedback on the above (realise that these have been covered in some previous threads, but it seems to be a developing market)



Its quite economical alright. There are a few reasons for this. UFH runs from a set of stats in each room. I have 3 rooms with big south facing windows. These 3 rooms would be in excess of 600 sq foot. Basically the UFH only comes on in these rooms in the evening after the suns goes down in the evening so I expect my usage to go up in the winter time. Also as I said my DHW isn't connected yet so this will need another 2/3 KWs once its connected though the Solar should take care of alot of this heating need from April to October.

As for storage. Well I have a friend who has a Kedco franchise so I got well advised on all the options. I basically have gone bagged for now but I am awaiting an outdoor silo which will store my 3.5 tonne. I will run my augur through the wall of the garage and in to this outdoor silo so I will have automated pellet feeding. Kedco are also supplying me with the pellets. The quality has been good so far anyway. As for rodents, I haven't heard anything about this before, any pellet storage area should be sealed tight anyway so they really shouldn't be able to get in there.


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## eroe (4 Jun 2007)

Hi
We have UFH on two floors of a 3 storey split level house. Rads in attic level, which are bedrooms. We used 250mm Thermo kind insulation (high ceilings and lots of glass) The quality of heat is fantastic. Reused existing kerosene boiler, planning to change to geo thermal when finances permit.
The rads are over sized (to allow for future change to geo-thermal) but saying that they are rarely turned on as the high level of insulation keeps all the heat in. One mistake we made was not putting in a heat exchange unit - they are very effective especially with UFH. Good Luck and get on to the UFH people asap.


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## mickeyg (5 Jun 2007)

Three have been discussions on various threads on the suitability of various types of timber floors for UFH. I am particularly interested in the suitability of solid wood flooring for UFH. Can anyone give me a definiive position on this.

m


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## keeper (5 Jun 2007)

eroe said:


> Hi
> We have UFH on two floors of a 3 storey split level house. Rads in attic level, which are bedrooms. We used 250mm Thermo kind insulation (high ceilings and lots of glass) The quality of heat is fantastic. Reused existing kerosene boiler, planning to change to geo thermal when finances permit.


eroe, can you give me a ball park on running the UFH with kerosene, and also guide on house size, my research so far says oil is very expensive for UFH, also Mrs Keeper likes her heat, so how many hours a day is it run?


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## eroe (5 Jun 2007)

Hi Keeper, are you sitting down? €1500 a year!! it is on about 6 hours per day in the middle of winter. (I like mrs keeper like a warm house!)
We have had it running 2 1/2 years like that (on a boiler which is 15+ years old) - and hope to get it down to 20% of that with geothermal when we install it. House is just over 2000sq ft. Hope that helps!


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## lfcjfc (5 Jun 2007)

Hi Eroe

As MickeyG says there are a lot of discussion threads on this - reading through them the cost in terms of electricity to run a Geothermal system was the subject of much debate. Reducing your costs to 20% of €1500 per year, ie €300 per year would be optimistic based on some experiences. To be honest it was the huge range of numbers quoted on geothermal running costs vs the capital expense that eventually turned me against it


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## eroe (5 Jun 2007)

Hi lfcjfc,
You may well be right but hopefully we can reduce from €1500! The environmental concern is also important for me.


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## keeper (6 Jun 2007)

eroe said:


> Hi lfcjfc,
> You may well be right but hopefully we can reduce from €1500! The environmental concern is also important for me.


 
Actually, €1500 for UFH on oil per annum does not seem too bad, what type of construction/insulation have you got. We have got several quotes for Ground Source/Borehole heat pumps, but these seem to start at about 15K+ and the skys the limit after that, and no-one is prepared to commit on actual running costs, which makes me more that a little wary. They all say use night rate electricity, but I don't really need the heat when we are asleep. Primary heating requirement will be mornings, evenings and weekends during the winter months, so I don't really see the savings for night rate electricity. Also the capital costs for heat pumps or a properly specced wood pellet boiler would buy a lot of oil.


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## Maurice Kell (7 Jun 2007)

When putting underfloor heating on a concrete slab unstairs should you lay directly onto the slab of put foil backed insulation down berofre laying the pipe work.


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## inchbyinch (8 Jun 2007)

Maurice

Welcome to AAM

I personally would lay insulation ,clip UFH onto that and float in screed. As if you were to leave it out the heat would radiate in all directions instead of just up you need to encourage the heat up as much as anything else other wise you will be using your first floor heating to heat your ground floor aswell.

As to how much, I would consult an expert. perhaps you could ask some of the people here who have installed it as real experts seem hard to find on this topic (i.e. people who have been at it years and know exactly what they are on about)

I would pay particular attention to your control system and temp stats, they are what will really make it efficent, its not really as simple as a boiler and rads which you can turn on and off, it needs to get information all the time.

Rgds
Inchy


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