Pros and cons to Underfloor Heating

no nails niall

Greeting All!,

In the process of making a few key decisions on a self build to start late spring.

Key decision required between rads or underfloor heating.
Having no experience of houses with underfloor heating I would be keen to know the views of people who have included this on their build.

I know a few people who are skeptical of the underfloor option, saying that it is madness to bury the heat under concrete and floor covering. It would seem that the rads would disperse the heat a lot more efficiently (although this may be an uneducated opinion!).

So whats the pros and cons?

Initially I would be drawn the the underfloor because we don't want rads on walls for aesthetic reasons. However I would guess that the underfloor option is more expensive.

Niall

Outkast_IRE

Best thing you can do to heat your house in insulate as much as possible , if your spending extra money in any area make it this one , it makes a huge difference , insulation and airtightness will really help ya out , by airtightness just make sure all window and door seals are working correct , door to attic isnt drafty leaving out heat. Othere will think of more things
once you have done this then pick oil or gas whichever you prefer

Whichever you go for make sure you get the highest efficency possible and have a good plumber who understands how to get the most out of it.


With regard to underfloor or rads to heat the house ,
You will only find underfloor good if the house is well insulated and good and airtight ,
Underfloor with the right controls , such as room thermostats ,timers , zones, is brilliant really nice comfortable type of heat. But you need a plumber and builders who know how to lay the pipes correctly and help ya get the most out of them .
Also if goin with underfloor , putting wooden floors down afterwards reduces the effectiveness of the system , when you have made more decisons about what system etc leave us know and more specific info can be given.
any more questions just ask i like underfloor.

The main downside seen by most is the long warmup and long cooldown time, thats the hardest adjustment to make but with good controls and everbody understanding how it works it shouldnt be a problem

no nails niall

Outkast_IRE wrote: »

Best thing you can do to heat your house in insulate as much as possible , if your spending extra money in any area make it this one , it makes a huge difference , insulation and airtightness will really help ya out , by airtightness just make sure all window and door seals are working correct , door to attic isnt drafty leaving out heat. Othere will think of more things
once you have done this then pick oil or gas whichever you prefer

Whichever you go for make sure you get the highest efficency possible and have a good plumber who understands how to get the most out of it.


With regard to underfloor or rads to heat the house ,
You will only find underfloor good if the house is well insulated and good and airtight ,
Underfloor with the right controls , such as room thermostats ,timers , zones, is brilliant really nice comfortable type of heat. But you need a plumber and builders who know how to lay the pipes correctly and help ya get the most out of them .
Also if goin with underfloor , putting wooden floors down afterwards reduces the effectiveness of the system , when you have made more decisons about what system etc leave us know and more specific info can be given.
any more questions just ask i like underfloor.

The main downside seen by most is the long warmup and long cooldown time, thats the hardest adjustment to make but with good controls and everbody understanding how it works it shouldnt be a problem

Good Info.

So if timber floors are out of the question and presumably carpets aswell, is the only remaining option tiles?

Niall

Outkast_IRE

no nails niall wrote: »

Good Info.

So if timber floors are out of the question and presumably carpets aswell, is the only remaining option tiles?

Niall

What i have seen very succesfully used are tiles that are imitation wood floor, i have been in houses where to the naked eye it looked like timber floor its only when you walk on it and feel how solid it is you realise its tile, i thought it looked nice.
No carpets arent out of the question they are fine but im not sure what the story is with the underlay you put under them as youd probably want the carpet straight on the concrete you might need to check that up , the problem with the wood is that it adds more mass to the floor and adds further to the long warm up /slow cool down times.It can still be used but its not reccomended.

Are you planning to use oil or gas to heat the underfloor ? In my opinion unless you have a very good modern plumber , i personally would get the underfloor plans made up by the material supplier, basically you give them the floor plans and heat loss values etc and they make up a drawing and list of all pipes, materials and what way to run the pipes for maximum efficency.

braftery

+1 for underfloor heating

We have underfloor heating powered by a ground source heat pump.
We have been living in the house for 4 years now.
We have tiled floors on the ground floor and engineered timber floor (18mm) on the upper floor.
We havedual metres and use night saver power

The underfloor heating is fantastic !

The rooms are all individually regulated and from jan to dec the temp of the room is more or less constant.

It makes the house so comfortable and the feel of heat is really "natural"

Is it more effecient ?

To be honest I dont know ... I dont have anything to compare it too ... but I am pretty sure that if I heated the house using oil the combined cost of electricity and oil would be greater than our bills now.

However, if it was less effecient I still would not change it ..

quality of life is worth a few euros a month !

I highly recommend it !!

PS: I do not sell underfloor heating !!

beyondpassive

Underfloor gives a radiant heat which is much more efficient and comfortable than the convective heat offered by rads.

Underfloor works very well in buildings with stable indoor temperatures, this is achieved by using insulations with good thermal storage properties, continuity of insulation, elimination of cold bridges and airtightness.

Building like this, have very small fluctuations in temp from day to day, so the ramp up load is small. Therefore the system does not have to be fast responce, 'revvin up' every 6 hours to bring the building from 14-20 degrees, instead it just 'purrs' along in the background keeping the thermal inertia of the fabric high and topping up the heat from 18-20 on demand.

As you have insulated to a higher level the heat load is reduced and so the area of underfloor needed to heat the house is reduced. In this way underfloor or low temp towel rails can be placed to wetrooms where the MHRV extracts that heat and exchanges it into the fresh air.

So while it suits to just have underfloor to tiled surfaced, because your heat source is fairly consistent, the wood floors can be acclimatised to the levels of humidity in the room.

Running the U-floor from a large combination buffer/cylinder works quite well as the solar keeps the middle of the tank over 35 degrees in the shoulder months.

no nails niall

beyondpassive wrote: »

Underfloor gives a radiant heat which is much more efficient and comfortable than the convective heat offered by rads.

Underfloor works very well in buildings with stable indoor temperatures, this is achieved by using insulations with good thermal storage properties, continuity of insulation, elimination of cold bridges and airtightness.

Building like this, have very small fluctuations in temp from day to day, so the ramp up load is small. Therefore the system does not have to be fast responce, 'revvin up' every 6 hours to bring the building from 14-20 degrees, instead it just 'purrs' along in the background keeping the thermal inertia of the fabric high and topping up the heat from 18-20 on demand.

As you have insulated to a higher level the heat load is reduced and so the area of underfloor needed to heat the house is reduced. In this way underfloor or low temp towel rails can be placed to wetrooms where the MHRV extracts that heat and exchanges it into the fresh air.

So while it suits to just have underfloor to tiled surfaced, because your heat source is fairly consistent, the wood floors can be acclimatised to the levels of humidity in the room.

Running the U-floor from a large combination buffer/cylinder works quite well as the solar keeps the middle of the tank over 35 degrees in the shoulder months.

Sounds good. We may include solar panels on a south facing mono pitch roof.

The main living/kitchen/dining space is open plan with the ceiling exposed to ridge level. This area will also have a large chimney with a muti fuel stove and possible back boiler.

I was thinking of only using underfloor in this main living space (6m x 11m) and open 5.6m to ridge level. The rest of the house, i.e. lower ground floor bedrooms, bathrooms, etc to have standard rads. These areas would be zoned.

Is it possible to combine underfloor with standard rads as described?

kboc

Outkast_IRE wrote: »

Best thing you can do to heat your house in insulate as much as possible , if your spending extra money in any area make it this one , it makes a huge difference , insulation and airtightness will really help ya out , by airtightness just make sure all window and door seals are working correct , door to attic isnt drafty leaving out heat. Othere will think of more things
once you have done this then pick oil or gas whichever you prefer

Whichever you go for make sure you get the highest efficency possible and have a good plumber who understands how to get the most out of it.


With regard to underfloor or rads to heat the house ,
You will only find underfloor good if the house is well insulated and good and airtight ,
Underfloor with the right controls , such as room thermostats ,timers , zones, is brilliant really nice comfortable type of heat. But you need a plumber and builders who know how to lay the pipes correctly and help ya get the most out of them .
Also if goin with underfloor , putting wooden floors down afterwards reduces the effectiveness of the system , when you have made more decisons about what system etc leave us know and more specific info can be given.
any more questions just ask i like underfloor.

The main downside seen by most is the long warmup and long cooldown time, thats the hardest adjustment to make but with good controls and everbody understanding how it works it shouldnt be a problem

100% correct.

I just turned on my UFH last week. Feels class. Regards the changing technology to heat houses in the short and meduim term, in my humble opinion most efficient technologies will work best with a system providing heat in a way that UFH does.

Good luck,

JuniorB

no nails niall wrote: »

I was thinking of only using underfloor in this main living space (6m x 11m) and open 5.6m to ridge level. The rest of the house, i.e. lower ground floor bedrooms, bathrooms, etc to have standard rads. These areas would be zoned.

Is it possible to combine underfloor with standard rads as described?

Yes it is. Use a buffer tank/thermal store. You can feed solar, back boiler and oil into it. That will use a mixing valve to release water to underfloor at 30 degrees or so and rads at 60 or 70 or whatever.

I'd go for underfloor in bathrooms as well - as that will be tiled and nice for the cold mornings!
We have underfloor all rooms downstairs and 2 bathrooms/ensuites upstairs, then rads in all bedrooms upstairs - reason ... easier to control rad temps and hope to leave them off 90% of the year.

Outkast_IRE

no nails niall wrote: »

Sounds good. We may include solar panels on a south facing mono pitch roof.

The main living/kitchen/dining space is open plan with the ceiling exposed to ridge level. This area will also have a large chimney with a muti fuel stove and possible back boiler.

I was thinking of only using underfloor in this main living space (6m x 11m) and open 5.6m to ridge level. The rest of the house, i.e. lower ground floor bedrooms, bathrooms, etc to have standard rads. These areas would be zoned.

Is it possible to combine underfloor with standard rads as described?

If you are goin to have rooms with high ceiling etc, i would defo reccomend getting a company to make up the underfloor layout/ spacings/ flowrates/plans etc the extra few quid now will make all the difference.
Have you decided oil or gas yet?

Personally im dead against combining both systems in a house it is easy to do and i know its been done etc and some people find it grand but , i think just stick with one or the other especially if its only one room for underfloor, they quite literally feel like two different types of heat and they both have vastly different warm up and cool down times, rather than just putting underfloor in one room i would reccomend two options go with all underfloor or go with all rads and get a very nice stylish radiator for your main living space.
Do you know anyone with a underfloor system that they are happy with that you could call into and see what it feels like?
It creates a really nice ambient temp, really nice to walk around in socks on.

As for solar panels ya sounds like a buffer tank is the way you want to go if you are having a stove or somethin else aswell, other wise a solar cylinder will do ya fine

imitation

Just to provide a counter viewpoint, I went with rads over UFH. UFH is a very comfortable form of heating, but as people mentioned, it has a ramp up time, and works most effectively when its left on for longer periods.

It has to be managed carefully, as if a room is too hot you can't simply turn off the rad for a fast response time. Some people can't get the hang of it initially, I've walked into a few ufh houses that were 23-25 degrees. I also think this could be a part reason why some people have reported huge bills with UFH, care needs to be taken with its design and usage to make it effective.

That being said, UFH is a more comfortable heat that the hot dry heat rads can produce, and warm tiles are pretty nice !

no nails niall

Outkast_IRE wrote: »

Have you decided oil or gas yet?


As for solar panels ya sounds like a buffer tank is the way you want to go if you are having a stove or somethin else aswell, other wise a solar cylinder will do ya fine

Oil is the only option as the house is in the countryside.

In order to cut down on the bills the intention is to use solar and multi fuel stove w/ backboiler to preheat water as much as possible.


How are bathroom towel radiators incorporated into a UFH system? Do they need to be plumbed independantly from the boiler? (If this is the case it would take considerable amount of piping in this particular build!)

Comments much appreciated.

Outkast_IRE

no nails niall wrote: »

Oil is the only option as the house is in the countryside.

In order to cut down on the bills the intention is to use solar and multi fuel stove w/ backboiler to preheat water as much as possible.


How are bathroom towel radiators incorporated into a UFH system? Do they need to be plumbed independantly from the boiler? (If this is the case it would take considerable amount of piping in this particular build!)

Comments much appreciated.

Well what a lot of people would do is have a system link in the hotpress or where the pipes from the boiler enter the house and the system link box allows you to split off to your different zones eg:hotwater/towel rails/underfloor. the underfloor would then have a mixing valve so water is delivered at the required cooler temps . Thats the basic idea anyway.

beyondpassive

The UFH and rads are taken from different parts of the tank, so its like seperate systems.

Make sure to not to have the boiler away from the house,, if the return temp cools on its way to the boiler.

Like everything else in post celtic bubble ireland construction, its all about quality of workmanship. The recession hasn't cleared out all the chancers

sonnenhaus as mentioned previously

www.sonnenhaus-institut.de/downloads/.../das_sonnenhaus_2009.pdf

psychhead

Hi all, has anybody here used UFH in conjunction with a solid fuel back boiler stove? If so how do you find it? We have a new extension that we would love to put underfloor in but the original part of the house has rads (all bedrooms) and we would like to keep them. Does the buffer tank work well or is it likely to cause problems?
Thanks!

galwaytt

psychhead wrote: »

Hi all, has anybody here used UFH in conjunction with a solid fuel back boiler stove? If so how do you find it? We have a new extension that we would love to put underfloor in but the original part of the house has rads (all bedrooms) and we would like to keep them. Does the buffer tank work well or is it likely to cause problems?
Thanks!

Installing a buffer tank just for one room is ott imho. You can buy a kit to tap into rad circuit to create a mini circuit for one room.

RKQ

From personal experience:-UFH downstairs with tiled and engineered timber floor - works great.Rads and towel rails up stairs - works great.Tank heated by solar panel and heat pump - works great, cheaper than oil.I think UFH gives a more natural heat, unlike the heat from a radiator.

mfceiling

I have a small question on underfloor...

If you are out of the house most of the day, say from 7.30 a.m to 6 p.m, is underfloor any use? Surely it's pointless running it all day when no one is there. Is there an argument for rads in this case?

howman

mfceiling wrote: »

I have a small question on underfloor...

If you are out of the house most of the day, say from 7.30 a.m to 6 p.m, is underfloor any use? Surely it's pointless running it all day when no one is there. Is there an argument for rads in this case?

Having the same thought myself, would your rads n oil boiler be just as/more efficient in this scenario, however probably not as comfy!

galwaytt

mfceiling wrote: »

I have a small question on underfloor...

If you are out of the house most of the day, say from 7.30 a.m to 6 p.m, is underfloor any use? Surely it's pointless running it all day when no one is there. Is there an argument for rads in this case?

..you're missing the point of UFH then. It's not a radiator, and doesn't perform like one, so having it on a short cycle like that is the wrong way to use it.

If you're house is well built, well insulated and highly airtight it won't be running "all day" anyway.

if your house has a particular heat demand, let's just pick a random number, say 25kW, then it is the same irrespective of rads or UFH supplying it.

You can have controls on UFH to keep the background heat level during the day at a different level, which is something you can't do with rads.

outside of that it's personal preference - me, I have UFH 20 years this year, now in house #2, so I'm a bit of convert

MicktheMan

galwaytt wrote: »

You can have controls on UFH to keep the background heat level during the day at a different level, which is something you can't do with rads.

Why not?

galwaytt

MicktheMan wrote: »

Why not?

...because std TRV's have no time control - which OP seems to want to be able to influence.

You can of course fit a manifold radiator system and motorised valves to the rads, and hook them up to a controller+stat's (to give a time function), but you're at the level of UFH at that stage.

mrsWhippy

Very informative thread, thanks.

I know there was mention of tiles being the optimal surface for UFH, but am dead set against tiles in the main living areas - is it still worth considering UFH if we're going to go with engineered hardwood?

MicktheMan

galwaytt wrote: »

You can have controls on UFH to keep the background heat level during the day at a different level, which is something you can't do with rads.

galwaytt wrote: »

You can of course fit a manifold radiator system and motorised valves to the rads, and hook them up to a controller+stat's (to give a time function), but you're at the level of UFH at that stage.

So you can so !:)

galwaytt

mrsWhippy wrote: »

Very informative thread, thanks.

I know there was mention of tiles being the optimal surface for UFH, but am dead set against tiles in the main living areas - is it still worth considering UFH if we're going to go with engineered hardwood?

Both work. I have a mix of laminate, engineered wood and tile in my house.

Tile in living space is nice if you find the right one. Forget traditional shapes and colours, they would be awful, but a nice modern, contemporary one could work.