Underfloor Heating

bdoo

Hi,

Planning is gone in and we're trying to make a good few decisions now before things really get going. One of the things we really can't decide on is underfloor or radiators for heating.

can anyone advise? House is about 280m2 i.5 storey.

JuniorB

Best of luck Bdoo .. not too far ahead of you. Stressful time. We're deffo going underfloor downstairs - reasons.. don't like the look of radiators, more even heat, OH likes the warm tile feel etc etc. Still not decided on the first floor. Might be as handy to put in UF but may not be used much.

Haven't seen too many say a bad word about HRV so would recommend that you research that anyway.

And get started on the window suppliers... long draw out process for us but we're finally getting there.

mr_edge_to_you

We've just kicked off 1 2100 sq ft house, almost finished sub floor. We're putting in ground source heat pump with UFH upstairs and downstairs.

From my relatively basic knowledge the issue you should be looking at is what source of heat are you expecting to use, not just radiator/UFH issue.

My research has shown to me that oil is very very expensive with UFH. UFH appears to be more suited to some of the newer renewable energy systems which give a more constant/ambient heat.

Best of luck with your build!

Mr Edge.

A country home

ill put a spanner in the works. . .
3rd option for you. . .

we are going for the tried and tested. . . rads. . .oil. . open fire (the later we both wont throw out)

anyway, , I wont say we didnt think about UFH/pumps etc. . .we consulted those who knew the business and also a few friends/friend of friends. . . . and from a personal exp we just decided for the usual way. .
but put everything we have into insulation. .
one thing we didnt want, which almost every told us you will loose and thats 100% control with UFH. . .
I have one guy working with me and i heard so many (its too hot, its too cold) . . i do know our temperatures are all over the place, great this day, cold that day. . and for UFH i just dont think this is for us. we are always looking for that quick flick of a switch and 15mins later hot rads. . .

in ref to the poster about not liking rads. . .well, all i can say is i know no different,, they haven been in almost every house in my 30 yrs. . so I guess they are like walls to me. . its just part of the building.. . lol. .

im sorry that we all here have different thoughts. . . but just make sure you go with whats happy with ye,
find out all info, talk to those in the know, best thing is to get honest people to comment on there own UFH. . ask yourself the pros and cons of each system. . .

hope this helps. .

Msmaloney26

In the same boat lads with UFH vs rads....waiting to kick off build and pulling my hair out with which system is best. I am 80% now on selecting UFH but just have to research every thing....it is a pain with costs involved and all the different opinions you get.
I am looking at oil based system ...not most efficent/cost effective maybe....still researching air to water heat pumps.....best of luck!

Juantorena

We've gone with UFH downstairs and have piped for alu rads upstairs with the hope that we won't need them (insulation levels, air-tightness, MHRV, etc.). Running off of ASHP.

Leadership

Just made the choice to to fit rads instead of UFH and pump the saving into insulation and alu rads. This was after consulting experts, people who have it and working out the physics of it.

The conclusion was a mix of rads and UFH between floors is a waste, all or nothting other wise the benifits of each cancel each other out and you have an uneconomical system.

ablelocks

mr_edge_to_you wrote: »

My research has shown to me that oil is very very expensive with UFH. UFH appears to be more suited to some of the newer renewable energy systems which give a more constant/ambient heat.
.

can you provide some links mr. edge? we were going to go with oil-fired boiler + radiators but our plumber is suggesting ufh as an alternative to the rads.

mr_edge_to_you

ablelocks wrote: »

can you provide some links mr. edge? we were going to go with oil-fired boiler + radiators but our plumber is suggesting ufh as an alternative to the rads.

unfortunately all my research on this was done the old fashioned way, on the streets! What we were told by contractors we got quotes from was the UFH doesn't lend itself to instant heat. For example, you're cold in the evening and you want to turn on the heat. With oil, rads will heat up instantly. UFH is much harder to heat as the heat has go through your screed and floor covering, therefore longer to get the temp up. To get proper heat out of UFH the heat needs to on for substantially longer, hence higher oil use. It really needs to be kept warm which would require more oil. If you use a heatpump it keeps a lower level of heat constant. That't about the best I can do, sorry.

bdoo

Thanks for all the replies,

I actually met a lad today about it, he recommended a thermal store heated by solar and topped up with oil heating when needed. Recommends room stats in each room and individual room zoning as opposed to upstairs /downstairs.

The thermal store is like your hot water tank but unlike the traditional system the water in the tank doesnt change and is always warm, UFH and Domestic H/W run in coils through the hot tank and take their heat from there when needed.

Think my mind is nearly made up...only thing is it's pricey enough!

xt40

i would not be convinced about the thermal store idea heated by solar panels.
i very much doubt it would heat the water to the 40 ish degs that it will need to be.
if anybody tells you it will work at 25, they are talking rubbish as the house would NEVER warm up to a comfortable room temp
stats in each room would be normal in a ufh system
i have and would recommend using an oil boiler
the way it works is
stat sends signal to ufh control box to switch on heating and open a valve on whetever zone(s)
boiler fires and heats water to 65-70 degs
thermostatic valve (40degs) lets the hot water into the ufh system where it is mixed with the cold water ufh return and then sent down the ufh flow at 40 degs the excess boiler water can then be diverted to heat rads upstairs etc

ufh might be slow to heat up but it is also slow to cool down and a million times better than rads

bauderline

I went for the following configuration in a 6000 sq ft house with UFH on three floors.

UFH Manifold on each floor with each room connecting back to a different port.
Stats in each room connected back to an actuator on each port.
200,000 BTU Oil Condensing Boiler
12 sqm of solar panels on south facing roof.
TiSun ProClean Buffer Tank 800L

The oil boiler will charge the buffer tank and operate off a differential temp sensor then UFH will run off buffer tank via a thermostatic valve.

Connecting oil boiler directly to UFH is not a good idea, makes it very inefficient.

The idea behind UFH is to maintain a constant temp in your home and with a properly tuned system in a well insulated house it will do just that.

TiSun Combination Tank PDF (worth reading)
http://www.rvr.ie/datastore/brochures/TiSun%20combination%20tanks.pdf

My 2 cents...

A country home

xt40 wrote: »

ufh might be slow to heat up but it is also slow to cool down and a million times better than rads

for the person asking the question here, just take note of the sentence above.

I would nearly say your last line is why some people are so confused. .

I for one dont like this element of UFH, and I know that alot of poeple are not aware of it. .

just something to point out. .

bauderline

A country home wrote: »

for the person asking the question here, just take note of the sentence above.

I would nearly say your last line is why some people are so confused. .

I for one dont like this element of UFH, and I know that alot of poeple are not aware of it. .

just something to point out. .

... well ... you really do have to abandon the idea of the conventional heating system when you use UFH. With conventional rads it is true that you can fluctuate the temperature of the house much more quickly... but that begs an important question.... why on earth would you want to do that ?!

Why not maintain a constant ambient temperature in the home, never too cold, never too warm... just right... that is why the stats in every room are important.. so that you can control and maintain this ambient temperature accurately...

A country home

bauderline wrote: »

... well ... you really do have to abandon the idea of the conventional heating system when you use UFH. With conventional rads it is true that you can fluctuate the temperature of the house much more quickly... but that begs an important question.... why on earth would you want to do that ?!

Why not maintain a constant ambient temperature in the home, never too cold, never too warm... just right... that is why the stats in every room are important.. so that you can control and maintain this ambient temperature accurately...

our climate is not constant. temps up temps down. . . . .3pm in the day can be one temp, and by 8pm you wish you could boost up the UFH.

I will say, that your neither right nor wrong, . . . this has been going on for yrs. . . . its one persons view over anothers. . I know its not the last of it on this board. .

sydthebeat

A country home wrote: »

our climate is not constant. temps up temps down. . . . .3pm in the day can be one temp, and by 8pm you wish you could boost up the UFH.

I will say, that your neither right nor wrong, . . . this has been going on for yrs. . . . its one persons view over anothers. . I know its not the last of it on this board. .

the whole idea of energy efficiency is to trap delivered heat.

it is so much more economical to maintain a constant temp than to maintain a heat up - cool down system.

apparently contrary to belief, ireland certainly does not have wide temperature fluctuations.... we have a fairly even temperature scale ... approx 3 deg in winter to approx 24-25 in summer.... compare that to mid europe where averages can go from as low as -12 to mid 30s in summer....

steming from this ireland is actually more sutited to ambient heating systems such as underfloor heating than europe, where its use is widespread...

BnA

I would have to disagree with you syd and agree with country house.

We're building approx 2800 sqft 1.5 story bungalow.

Our initial plan was to go Geothermal / Underfloor. However we read so so many mixed reports about Geothermal that they, (along with the massive cost of drilling etc) turned us off it.

We then though we'd put in UFH in the downstairs and old fashioned rads upstairs and run it all off oil. OUr idea was that by putting in the UFH now downstairs, maybe in a few years when we had a bit of money and maybe more confidence in geothermal technology, we could switch over to it. But my plumber (who's a good friend) put me right off it. As he pointed out, yes, ufh keeps rooms at a constant ambient temp all day. But that is an awful waste of money in a bedroom where all you want is a quick blast of heat half an hour before you go to bed and maybe another blast in the morning.

So then we went to UFH in the living area only with another heat source (some kind of stove) to give the room a blast on an evening when it is unexpectedly cold and you don't have the ufh turned on. This was our plan for a long time.

But just today after talking to the plumber again and another friend who works in plumbing supplies, I am thinking we'll throw out the under floor altogether. We are gaining nothing from it. Yes the tiles might be nice and warm, but it will cost a fortune to run, be more expensive to install, and has much greater potential to give trouble in the future. If a Rad gives you trouble, the worst you'll have to do, is take it off the wall and replace it. If your UFH starts acting up, it could be out with the pick and shovel and down you go through the lovely marble tiles...

One bit of advice that I did get today though that I think is very well worth passing on. If you do decide to go for UFH (particularly if you go Geothermal as well) , be very very very careful about who you get to install it. There are an awful lot of cowboys out there. A bog standard rad type system can be repaired easily enough, but a poorly installed UFH system is nothing short of a total nightmare.

RE Syds point about Irelands Climate being suitable, I'd have to disagree. The Irish climate might not have as extreme temps as other parts of Europe, but we have much more flucuations on a day to day basis. That's what makes UFH unsuitable. In Ireland you often don't know if you will need the heating untill you get up in the morning or untill you get home in the evening. With UFH, that's too late.

sinnerboy

Many clients have told me - UFH - best thing ever . Others - never again .

Coffee or tea ? There is no universal answer.

Neither rads nor UFH ought to be more expensive . Simple physics .
Rads circulate less water at higher temp . UFH circulates more water at lower temp . The heat energy ( and fuel consumed ) in theory should be the same .

User behavior mucks it up however . Some never really adjust to UFH , turning it on too soon , off too late - once bitten twice shy by a cold snap . And then go about opening windows to dump heat ( and €€€'s ) on that "surprisingly" warm afternoon . Avoid this "trap" and UFH won't cost any more to run than rads .

bauderline

bauderline wrote: »

I went for the following configuration in a 6000 sq ft house with UFH on three floors.

UFH Manifold on each floor with each room connecting back to a different port.
Stats in each room connected back to an actuator on each port.
200,000 BTU Oil Condensing Boiler
12 sqm of solar panels on south facing roof.
TiSun ProClean Buffer Tank 800L

The oil boiler will charge the buffer tank and operate off a differential temp sensor then UFH will run off buffer tank via a thermostatic valve.

Connecting oil boiler directly to UFH is not a good idea, makes it very inefficient.

The idea behind UFH is to maintain a constant temp in your home and with a properly tuned system in a well insulated house it will do just that.

TiSun Combination Tank PDF (worth reading)
http://www.rvr.ie/datastore/brochures/TiSun%20combination%20tanks.pdf

My 2 cents...

Very similar to my system, 100% happy with it.

sydthebeat

BnA wrote: »

But that is an awful waste of money in a bedroom where all you want is a quick blast of heat half an hour before you go to bed and maybe another blast in the morning.

So then we went to UFH in the living area only with another heat source (some kind of stove) to give the room a blast on an evening when it is unexpectedly cold and you don't have the ufh turned on. This was our plan for a long time.

But just today after talking to the plumber again and another friend who works in plumbing supplies, I am thinking we'll throw out the under floor altogether. We are gaining nothing from it. Yes the tiles might be nice and warm, but it will cost a fortune to run, be more expensive to install, and has much greater potential to give trouble in the future. If a Rad gives you trouble, the worst you'll have to do, is take it off the wall and replace it. If your UFH starts acting up, it could be out with the pick and shovel and down you go through the lovely marble tiles...

One bit of advice that I did get today though that I think is very well worth passing on. If you do decide to go for UFH (particularly if you go Geothermal as well) , be very very very careful about who you get to install it. There are an awful lot of cowboys out there. A bog standard rad type system can be repaired easily enough, but a poorly installed UFH system is nothing short of a total nightmare.

RE Syds point about Irelands Climate being suitable, I'd have to disagree. The Irish climate might not have as extreme temps as other parts of Europe, but we have much more flucuations on a day to day basis. That's what makes UFH unsuitable. In Ireland you often don't know if you will need the heating untill you get up in the morning or untill you get home in the evening. With UFH, that's too late.

we'll agree to disagree....

need a 'quick blast' is an auld oirish way of thinking. The whole point of a high level of insulation and air tightness is there is always a constant temperature....
is it more efficient to keep a room at 18 degrees all day or to heat it from say 14 deg to 21 deg twice a day.... well, if you have taken all teh measures to reduce heat loss, it is more efficient to keep the room a constant temp.

we are so used to very very bad standards of construction we are programmed into assuming the worst. We close doors to keep the heat in rooms, while our european friends leave doors open (or open plan living) to encourage the free movement of heat currents throught the house...
Its simply a mindset we need to get out of. Yes, we are right to be wary of construction standards.... but that shouldnt mean we cannot demand the best!

again, the argument that in ireland 'sure, we dont know one day from another what the weather will be life'... doesnt cut it. The effect of temperature fluctuations outside are minimised with a high level of insulation and air tightness.. and im not talking about current regulation standards! Middle europe can see temp swings in spring and autumn from say -5 at night to 24 during the day (approx a 30 deg swing)..... the most we see would be from say 5 to 15 (or a 7-10 deg swing)... This would negate your argument about our unsure weather. Its actual an indictment on our construct standards that such a low temperature swing can have such an effect on our comfort of living!!

the rate of heat loss depends on three main factors:
1. the temperature differential between inside and outside.
In every case europeans have a higher temp differential
2. the level of insulation... obvious
3. the level of air leakage... we call this air tightness.

sydthebeat

sydthebeat wrote: »

the whole idea of energy efficiency is to trap delivered heat.

it is so much more economical to maintain a constant temp than to maintain a heat up - cool down system.

apparently contrary to belief, ireland certainly does not have wide temperature fluctuations.... we have a fairly even temperature scale ... approx 3 deg in winter to approx 24-25 in summer.... compare that to mid europe where averages can go from as low as -12 to mid 30s in summer....

steming from this ireland is actually more sutited to ambient heating systems such as underfloor heating than europe, where its use is widespread...

I tend to agree with this, I have my system set up to run about three hours in the morning and five in the afternoon/evening, the thermostatic mixer valve is set to 35C and I never find any cold spots.

But most importantly I have the house very well insulated & MHRV installed!

bauderline

I would say a lot of the negative reports on UFH are from people with poorly installed/configured systems and/or poorly constructed houses.

syd sort of touched on this, but a well insulated and air tight house should protect the interior temperature of the house from rapid exterior temperature fluctuations providing more than enough time for the UFH system to react.

I contend strongly that a properly installed and configured UFH system in a suitably constructed house will provide a far superior living environment than a rad based system.

... ok I see syd has posted again in the meantime... saying the same thing but better....

BnA

sydthebeat wrote: »

we'll agree to disagree....

...is it more efficient to keep a room at 18 degrees all day or to heat it from say 14 deg to 21 deg twice a day.... well, if you have taken all teh measures to reduce heat loss, it is more efficient to keep the room a constant temp.

I'm very sceptical about this.

If you have two rooms with the same level of air tightness/insulation etc I do not believe that it would use less energy to keep the room at a constant temp of 18 degrees, 24 hours a day than it would be to turn on a rad for 1.5 hours in the day.

Also, a good UFH system requires a high level of air tightness in a house and I am certainly not convinced that this is healthy. I know you can use heat recovery units to change the air in the house for you while utilising the heat in the air you are extracting, but you are looking at an awful lot of expense when you combine this with the cost of the UFH system.

bauderline

1.5 hours a day !!??

That would seem a bit on the low side... however taking into account that both rooms are equally well insulated and air tight then I would question if the UFH in that room would be activated much longer than 1.5 hours. Don't forget the screed acts like a giant storage heater so it will give off heat long after a radiator has cooled down. Also take into account the much lower temperature the UFH operates at which means less energy used as well..

The one thing I will give you is that the more time you spend in the house the greater the return you will get from UFH.

A pet hate of mine in rad based systems is the shutting down of the heating system before going to bed. In the middle of winter the house gets really cold during the night... any trips to the loo and the words "... I may be gone for some time" spring to mind...

BnA

bauderline wrote: »

1.5 hours a day !!??

That would seem a bit on the low side... however taking into account that both rooms are equally well insulated and air tight then I would question if the UFH in that room would be activated much longer than 1.5 hours. Don't forget the screed acts like a giant storage heater so it will give off heat long after a radiator has cooled down. Also take into account the much lower temperature the UFH operates at which means less energy used as well..

The one thing I will give you is that the more time you spend in the house the greater the return you will get from UFH.

A pet hate of mine in rad based systems is the shutting down of the heating system before going to bed. In the middle of winter the house gets really cold during the night... any trips to the loo and the words "... I may be gone for some time" spring to mind...

Yeah..... I might have been a bit optimistic with my 1.5 hours a day.

After doing my research on the net and spending a lot of time talking to people in the trade / building houses themselves etc over the last few years, I am about 2 weeks away from putting in the first fixing of my plumbing, and I'm still not 100% sure what I will go for. The only 100% definate conclusion that I have come to is that there are a lot of confliction reports out there and there is a lot of mis-information out there.

On one hand, I feel there are a lot of people who are pushing a green agenda and who latch onto a particular system because it is being marketed as the next big green thing without actually doing genuine research into it.

Then, you will have a lot of people who will dismiss systems because they are too expensive without actually looking into the long term payback on the system.

Also, as mentioned a few times on this thread, a lot of new technologies, get a bad name because they were just poorly installed.

All in all, I found it is very very difficult to cut through all the bull that is out there to get down to the hard facts and try and see what is the best genuine system for your house.

sydthebeat

BnA wrote: »

Yeah..... I might have been a bit optimistic with my 1.5 hours a day.

After doing my research on the net and spending a lot of time talking to people in the trade / building houses themselves etc over the last few years, I am about 2 weeks away from putting in the first fixing of my plumbing, and I'm still not 100% sure what I will go for. The only 100% definate conclusion that I have come to is that there are a lot of confliction reports out there and there is a lot of mis-information out there.

On one hand, I feel there are a lot of people who are pushing a green agenda and who latch onto a particular system because it is being marketed as the next big green thing without actually doing genuine research into it.

Then, you will have a lot of people who will dismiss systems because they are too expensive without actually looking into the long term payback on the system.

Also, as mentioned a few times on this thread, a lot of new technologies, get a bad name because they were just poorly installed.

All in all, I found it is very very difficult to cut through all the bull that is out there to get down to the hard facts and try and see what is the best genuine system for your house.

bna... i completely agree that theres a huge amount of conflicting advice out there...

in regard to your situation i would put the decision like this...

are you incorporating a MHRV system...??

If no, i wouldnt go with an UFH system...

If yes, the viability of an UFH system is GREATLY increased...

Juantorena

BnA wrote: »

Yeah..... I might have been a bit optimistic with my 1.5 hours a day.

After doing my research on the net and spending a lot of time talking to people in the trade / building houses themselves etc over the last few years, I am about 2 weeks away from putting in the first fixing of my plumbing, and I'm still not 100% sure what I will go for. The only 100% definate conclusion that I have come to is that there are a lot of confliction reports out there and there is a lot of mis-information out there.

On one hand, I feel there are a lot of people who are pushing a green agenda and who latch onto a particular system because it is being marketed as the next big green thing without actually doing genuine research into it.

Then, you will have a lot of people who will dismiss systems because they are too expensive without actually looking into the long term payback on the system.

Also, as mentioned a few times on this thread, a lot of new technologies, get a bad name because they were just poorly installed.

All in all, I found it is very very difficult to cut through all the bull that is out there to get down to the hard facts and try and see what is the best genuine system for your house.

Not to derail the thread but have to agree with you, BnA. I have agonised (yes, literally!) over the heating system/method(s) for the house and finally came to these realisations: you'll never get the 'perfect' system; what you do go with will be outdated in 3-5 years time and your own personal circumstances/habits will determine the eventual success or otherwise of your choices.

At some point you need to draw a line and - with an informed, if that's possible, mindset - just go with your instincts. I am wide open to the possibility of getting the heating mix wrong...whether or not we enjoy the house will be the ultimate determinant of success or 'failure' for me.

What I would say though is that, as has been said on here many a time, there are ways to reduce how 'wrong' you get it...reduce the heating requirement int'-first place!

NextSteps

Just from personal experience - we have UFH downstairs and rads upstairs (bedrooms which don't need to be heated except morining and for an hour in the evening). For us, UFH would be a total waste upstairs - about 22 hours a day of unneeded heating.

But downstairs, we've found it to be very good, constantly the heat has been just about right. Over the last year or two, we've occasionally opened windows to adjust the heat (in spring, when we weren't ready to turn the heat off altogether), and occasionally lit a fire - but that was for atmosphere, not comfort. Plus, we haven't been always closing doors to keep the heat in whichever room we're in, as you might with a rad system.

People are always saying how warm and cosy the house is, and I love the warm tiles and floorboards. (So does the cat.)

In terms of cost, I'm not sure - there have been so many other variables since we changed the house (solar panels, insulation, new gas boiler) that I can't measure the difference in our bills.

Hope this helps.

sinnerboy

BnA wrote: »

If you have two rooms with the same level of air tightness/insulation etc I do not believe that it would use less energy to keep the room at a constant temp of 18 degrees, 24 hours a day than it would be to turn on a rad for 1.5 hours in the day.

2 identical rooms one Rads , one UFH will require the same energy to achieve the same temp . Simple law of physics .

sinnerboy

sinnerboy wrote: »

2 identical rooms one Rads , one UFH will require the same energy to achieve the same temp . Simple law of physics .

True over a 24 hour period, except that the radiator is on for only 1.5 hours of the day that room will experience a large tepmerature variation, the UFH (with a concrete floor) will easily maintain the same temperature.

kkhurler

When we put in UFH we were sold it as a way of life rather than a heating system and i think that this adequately reflects exactly what it is. you dont turn it on and off you have min and max temperatures and this is how to best regulate it - however if you have a warm day and snow the next UFH is not that adaptable - it takes a while to get rooms to required comfortable temp. i wouldnt change it - but if i had smaller rooms i would look more favourably on radiators.

sinnerboy

Deleted User wrote: »

True over a 24 hour period, except that the radiator is on for only 1.5 hours of the day that room will experience a large tepmerature variation, the UFH (with a concrete floor) will easily maintain the same temperature.

Agreed . Slow steady release of heat is much better .

kkhurler

kkhurler wrote: »

however if you have a warm day and snow the next UFH is not that adaptable - it takes a while to get rooms to required comfortable temp.

This is easily resolved by using an intelligent control system that measures outside temperature and/or extremely good insulation.

redonly

I am in a similar situtation to with the ufh versus rads decision need to make a decision fast so any help would be much appreciated!


3000 sqfoot story and a 1/2 with precast floors.

Not putting in HRV

This is what i have (provisionally) come up with:

option 1

oil condenseing boiler:

Ufh down stairs with 100mm of xtratherm insulation and a max of 50mm sceeedflo or simillar

8 zones with thermostats in each zone/room

Rads upstairs

can this work? pros and cons?

---

option 2

as option 1 but instead of rads upstairs put ufh with 7 zones/rooms with thermostats at each zone/room.

50mm of insulation and screed (not sure how much screed yet)

With Screedflo are the response times better than with concrete?

I will put in the pipework for a heatpump to be considered down the road.

___________________________________________

other things to consider.

4sqm of flat plate solar panels and a triple coil ss tank

Multifuel stove with a back boiler.

Help

redonly

A country home

bauderline wrote: »

I would say a lot of the negative reports on UFH are from people with poorly installed/configured systems and/or poorly constructed houses

this is probably the number one reply when someone complains about UFH. and i personally think there is too many people being pointed at.
its probably my number one concern, everyone blaming the other, installer/manufacture/customer/. if the esb cuts out i will ring one fone number and they are responsible.. ..

anyway. . have we not settled this debate yet. i see we are on 3 pages already . .
jury is out ok, they are gone out, and have been out, ( think they escaped through a back entrance)

sydthebeat

A country home wrote: »

this is probably the number one reply when someone complains about UFH. and i personally think there is too many people being pointed at.
its probably my number one concern, everyone blaming the other, installer/manufacture/customer/. if the esb cuts out i will ring one fone number and they are responsible.. ..

anyway. . have we not settled this debate yet. i see we are on 3 pages already . .
jury is out ok, they are gone out, and have been out, ( think they escaped through a back entrance)

not sure,... my view..

if building to minimum regs, basic air tightness, no HRV, bsic oil boiler..... then use a rad system... UFH is not for you...

however, if building above min standards, using HRV in a respectably air tight house (Q 50 = 5 or less!!).. using condensing oil boiler, wood pellet, or geothermal... then UFH is well suited....

mr_edge_to_you

The OP must be really confused now!!

mr_edge_to_you

mr_edge_to_you wrote: »

The OP must be really confused now!!

Not if he follows the advice below.

sydthebeat wrote: »

not sure,... my view..

if building to minimum regs, basic air tightness, no HRV, bsic oil boiler..... then use a rad system... UFH is not for you...

however, if building above min standards, using HRV in a respectably air tight house (Q 50 = 5 or less!!).. using condensing oil boiler, wood pellet, or geothermal... then UFH is well suited....

bdoo

Confused?...Never!

Thanks for all the advice, I'm hoping to go the whole way with HRV and air tightness, so prob will go for it.

Thanks again.

Jennyr

Hi

I created another thread on this topic, didn't see this one. Sorry about that.

We are just about to start our house. It's a 2 storey, 2500sq ft house with living area upstairs and down. We are planning to install MHRV and plan to insulate well. I see on some of the replies here that people are only using it on the groundfloor. As we have living area upstairs we plan to use it on both floors.

We are planning to use oil but also a solid fuel stove as we have a supply of timber as a bye product of my husbands business.

One plumber told us that you cannot use UFH with a solid fuel stove but another told us you can if you get a special hot water tank. It seems to be the same one that someone left a link to in a previous post.

So any advice if it will work??

Jennyr

Jennyr wrote: »

One plumber told us that you cannot use UFH with a solid fuel stove but another told us you can if you get a special hot water tank. It seems to be the same one that someone left a link to in a previous post.

So any advice if it will work??

A thermal store is a very good way to transfer the heat from the stove, as it allows both elements to work independantly.

The stove can be fired up at any convenient time to "charge" up the tank and the UFH can draw on this heat whenever it's needed.

The most important part of the system is the thermostatic mixer valve that regulates the temperature from the tank to the UFH.

B-Links

Hi - interesting discussions here.
I have a question on a related topic which I am hoping someone among you may have come across.

I am building a 40m2 extension behind my house. I intend to install underfloor heating in the downstairs room which will be the kitchen (mainly comfort and aesthetic reasons) - area 20m2.
The floor is a single pour slab with build up as follows: hardcore/blinding/radon barrier/150mm insulation/125mm mesh reinforced concrete floor
The concrete floor will be polished and that will be the final floor finish.
The North and West walls will be very well insulated, the East wall is the existing back wall of the old house, the South wall is a glass conservatory (with blinds).

I have a few concerns with regard to undefloor heating in this configuration:

1. the slab is the finished floor. Is there a risk of cracking due the expansion/contraction in the long tem related to underfloor heating? I wouldn't have thought so but normally you don't see the slab under floor finishes. The floor will be cured properly, allowed to dry out and heated slowly.
2. Is it better/does it make any difference to put the pipes at the bottom above the insulation or in the middle above the mesh?
3. Control - the are is only 20m2, kitchen so area generating heat, possible high solar gain in winter through conservatory (summer not sn issue) - I wionder if it will be difficult to maintain a comfortable temperature in this room with ufh?

Would appreciate your thoughts on this.
Thanks.

bauderline

You are getting into dodgey territory with this concept...

Your biggest problem is subsidence in the 150mm insulation and issues where there are joins in the insulation sheets.

If nothing else I would say that you WILL get hairline cracks....

No way I would go for that setup....

P.

CJhaughey

B-Links wrote: »

Hi - interesting discussions here.
I have a question on a related topic which I am hoping someone among you may have come across.

I am building a 40m2 extension behind my house. I intend to install underfloor heating in the downstairs room which will be the kitchen (mainly comfort and aesthetic reasons) - area 20m2.
The floor is a single pour slab with build up as follows: hardcore/blinding/radon barrier/150mm insulation/125mm mesh reinforced concrete floor
The concrete floor will be polished and that will be the final floor finish.
The North and West walls will be very well insulated, the East wall is the existing back wall of the old house, the South wall is a glass conservatory (with blinds).


Thanks.

My house has a similar construction, but there is a layer of 3/4 washed gravel in the middle of the slab about 1 ft in from the edge.

I did have one crack in the slab, not very big and about 1mm in width.
The electric UFH wires and the Pex pipework were cable tied back to the mesh.

Overall no problems however the company that did this build have a lot of experience doing this.
There is also an insulated Cill that sits at the edge of the slab and forms part of the shuttering.

AdamAntsy

I'm also struggling with the choice of UFH or Rads. I'm for UFH, wife against - and they're always right or so I'm told

Planning an ICF build, MHRV installed, decent windows & insulation to get a nice cosy house. So given that I'm not sure how much input and how often we'll require the heat to be 'on' (a lot of good marketing on the warmth of ICF from suppliers there).

In such a case, is it worthwhile to install an expensive UFH system that is dormant for a long period or just stick in rads and thermo's to switch them on if room temp < threshold?

This has to be one of the hottest topics as everyone and (especially) their cat has an opinion, and it's all different :rolleyes:

Finally - with UFH an engineer was telling me the regs for floor u-Value is 0.15, and 100mm kingspan is unlikely to meet that. In that case, is there a standard way to get around the subsidence mentioned for 150mm insulation in the floor?

MaryBurton

I'm heating my new house (2,700ft) with a ********** Heat Pump and under-floor downstairs and ordinary rads upstairs. My brother is a plumber and he put it in. They supplied everything to him. I'm delighted with the whole system. He said it was really easy to put in. Plenty of hot water, and plenty of control, although under-floor is not everyone's cup of tea.

A friend of mine also has a *********** Heat Pump but they have fan-coils which*********also make. The main difference is their house heats up in 15mins from cold, and each room is controlled by it's own thermostat so there's lots of control too, but I think their house is a bit cheaper to heat too. They don't feel too hot on warm sunny days in winter like we do, because our floor has already warmed up before we knew it was going to be a warm and sunny day whereas their heating comes on and shuts off quicker, so they safe that way.

I believe they now give the option of air or water source heat pumps, and fan-coils or under-floor, and are also now offer DIY kits for the under-floor too. I can't remember the name of the person I was dealing with there but very helpful. Their web-site is www.**************.com and it has most of the brochures available in pdf format to download to compare.

johnwstafford

Hi Donalbaker,

Is it costing you much to run the system? How big is your build and how much of it is heated with UFH?
I was talking to a plumber (Old Skool) who doesn't like UFH. His argument is that there is so much water to heat that it's not worth it. I really want to go with this system but would hate to be paying potentially thousands a year to run it.