Underfloor heating and insulation questions

A

August

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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?
 
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.
 
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.
 
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.
 
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.

"
this advice is wrong . you dont need to do anything to your rads . the ufh ystem would have a thermostatically controlled valve/mixer set which reduces to the temp in the ufh circuit to 25-40 by pumping the same water round and round each ufh loop , only letting small amounts of water as required from the main rad/boiler circuit (60-70 degs) to maintain the set ufh pipe temp.
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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.
 
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.
 
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.......
 
Thanks for that. Have a lot of it buried in concrete floors - perish the thought it would fail
 
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..........:D
 
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
 
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.......
 
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
 
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.
 
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
 
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.
 
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.
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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.
 
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.
Click to expand...

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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