Apologies for raising this venerable topic again but I do have a specific
question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good for
maintaining an even temperature over a long time but poor at rapidly heating
up a cold environment. But I've read in a couple of places that recent
developments in design have made it much more responsive much more quickly.

Is that actually the case?

Many thanks.

On 26/05/16 11:30, Bert Coules wrote:
Apologies for raising this venerable topic again but I do have a
specific question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good
for maintaining an even temperature over a long time but poor at rapidly
heating up a cold environment. But I've read in a couple of places that
recent developments in design have made it much more responsive much
more quickly.

Is that actually the case?


It really depends.


In screed has a huge mass to get warm before it really gets going.

Conversely it stays warm all night....

Under floorboards in the void is far less thermal mass.


Many thanks.



--
Microsoft : the best reason to go to Linux that ever existed.

Thanks for the speedy reply. The flooring at present is T&G boards over a
deep (3ft, I think) void, so heat-up times might not be too bad.

I asked the question because I'm planning an extensive renovation and
extension to my sixties semi-detached bungalow, currently heated with
conventional radiators and an open-flame gas fire. The property is almost
completely open-plan with only the bathroom as a separate room, and this
arrangement will be kept for the extension and the new first floor.

I need a system which can regularly and quickly heat up the whole of the
house from cold: even in warm weather the internal temperature can drop
rapidly in the evenings. But because the drop can be unpredictable I don't
run the present system on a timer: I use a master wall-mounted thermostat to
switch the heating on when it's needed and to adjust it thereafter.

I like the idea of doing away with the wall-occupying radiators but I'm not
sure that UFH is really ideal for my needs.

On 26/05/16 12:17, Bert Coules wrote:
I need a system which can regularly and quickly heat up the whole of the
house from cold: even in warm weather the internal temperature can drop
rapidly in the evenings.

IF you have a huge screed with in-screed pipework heating it, it wont
drop like a stone in the evenings!


But because the drop can be unpredictable I
don't run the present system on a timer: I use a master wall-mounted
thermostat to switch the heating on when it's needed and to adjust it
thereafter.


Arte you in the house all day?

What is the wall construction?

What is the floor construction?



I like the idea of doing away with the wall-occupying radiators but I'm
not sure that UFH is really ideal for my needs.

I am not sure what your needs really are. See above.

If you have blockwork wall, are in the house all day and have or would
be happy to install an INSULATED solid floor, UFH would suit very well
BUT you need at least 3" of screed over at least 3" of insulation to do
an inscreed floor.

Similar insulation with pipes under a chip or ply floor will work too.


--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On Thu, 26 May 2016 12:17:58 +0100, "Bert Coules"
wrote:

Thanks for the speedy reply. The flooring at present is T&G boards over a
deep (3ft, I think) void, so heat-up times might not be too bad.

Mounting UFH in aluminium heat spreader plates under the floorboards
is quite common in upstairs rooms. We have those. There is no reason
why you couldn't do the same downstairs laying them on top of
something like kingspan to stop heat loss downwards. However, the
lower water temperature will still give you slower heat up times
compared with radiators.

I asked the question because I'm planning an extensive renovation and
extension to my sixties semi-detached bungalow, currently heated with
conventional radiators and an open-flame gas fire. The property is almost
completely open-plan with only the bathroom as a separate room, and this
arrangement will be kept for the extension and the new first floor.

I need a system which can regularly and quickly heat up the whole of the
house from cold: even in warm weather the internal temperature can drop
rapidly in the evenings. But because the drop can be unpredictable I don't
run the present system on a timer: I use a master wall-mounted thermostat to
switch the heating on when it's needed and to adjust it thereafter.

I like the idea of doing away with the wall-occupying radiators but I'm not
sure that UFH is really ideal for my needs.

Use a predictive controller such as those shown here :-

http://www.trustedreviews.com/opinio...thermostats-uk
http://www.thegreenage.co.uk/intelli...l-thermostats/

On 26/05/2016 11:30, Bert Coules wrote:
Apologies for raising this venerable topic again but I do have a
specific question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good
for maintaining an even temperature over a long time but poor at rapidly
heating up a cold environment. But I've read in a couple of places that
recent developments in design have made it much more responsive much
more quickly.

Is that actually the case?

Much depends on how its installed. If its on top of a significant layer
of insulation, and not covered by a particularly insulating floor
covering, then it will be far more responsive than if installed for
example under a concrete slab.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 26/05/2016 11:30, Bert Coules wrote:
Apologies for raising this venerable topic again but I do have a
specific question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good
for maintaining an even temperature over a long time but poor at rapidly
heating up a cold environment. But I've read in a couple of places that
recent developments in design have made it much more responsive much
more quickly.

Is that actually the case?

Many thanks.

We have been looking at houses to buy for many months. Some of the
otherwise fairly attractive houses we looked at (on paper/screen) were
rejected because they had underfloor heating. Some people just cannot
cope with underfloor heating and would actually rather have underfloor
cooling, if anything, much of the year.

(It is different if the house can sensibly be heated by other means, so
an electric bathroom floor you can just switch off would not have been a
deal-killer. But when the whole place is designed for it, changing to
another heating system can be awkward.)

Weir-Mitchell disease

--
Rod

On 26/05/16 18:41, polygonum wrote:
On 26/05/2016 11:30, Bert Coules wrote:
Apologies for raising this venerable topic again but I do have a
specific question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good
for maintaining an even temperature over a long time but poor at rapidly
heating up a cold environment. But I've read in a couple of places that
recent developments in design have made it much more responsive much
more quickly.

Is that actually the case?

Many thanks.

We have been looking at houses to buy for many months. Some of the
otherwise fairly attractive houses we looked at (on paper/screen) were
rejected because they had underfloor heating. Some people just cannot
cope with underfloor heating and would actually rather have underfloor
cooling, if anything, much of the year.

(It is different if the house can sensibly be heated by other means, so
an electric bathroom floor you can just switch off would not have been a
deal-killer. But when the whole place is designed for it, changing to
another heating system can be awkward.)

Weir-Mitchell disease

It remains my favourite heating system of all time. Hot air second


--
€œSome people like to travel by train because it combines the slowness of
a car with the cramped public exposure of €¨an airplane.€�

Dennis Miller

On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating. The thought of it becoming more
widespread is not pleasant.

I have never experienced even vaguely satisfactory warmed air heating.

--
Rod

On 26/05/2016 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating. The thought of it becoming more
widespread is not pleasant.


In what way does your partner (and other users) suffer with underfloor
heating?


--
Cheers, Rob

On 26/05/2016 19:22, RJH wrote:
On 26/05/2016 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating. The thought of it becoming more
widespread is not pleasant.


In what way does your partner (and other users) suffer with underfloor
heating?


Severe pain in feet and legs. Seems to be moving up and also affecting
hands a bit. There are quite a number of videos - mostly poorly
presented/filmed or very individual. This is better than many:

https://www.youtube.com/watch?v=m7CTUjoHnOU

--
Rod

On 26/05/16 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating.

Why?

The thought of it becoming more
widespread is not pleasant.


I am at a loss to understand your bigotry

I have never experienced even vaguely satisfactory warmed air heating.

Never been to a supermarket?


--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On 26/05/16 19:56, polygonum wrote:
On 26/05/2016 19:22, RJH wrote:
On 26/05/2016 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating. The thought of it becoming more
widespread is not pleasant.


In what way does your partner (and other users) suffer with underfloor
heating?


Severe pain in feet and legs. Seems to be moving up and also affecting
hands a bit. There are quite a number of videos - mostly poorly
presented/filmed or very individual. This is better than many:

https://www.youtube.com/watch?v=m7CTUjoHnOU

WTF has that to do with underfloor heating?


--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell

On 26/05/2016 20:13, The Natural Philosopher wrote:

WTF has that to do with underfloor heating?

Because warm floors cause the flares which are so painful. I have
witnessed it many times in seemingly trivial situations such as where a
hot water pipe runs under a floor. Or walking on paving that has warmed
up in the sun. Not talking about barefoot on scorched ground - just
spring or autumn slight warmth.

The best floor for it is probably cool ceramic.

--
Rod

On 26/05/16 20:39, polygonum wrote:
On 26/05/2016 20:13, The Natural Philosopher wrote:

WTF has that to do with underfloor heating?

Because warm floors cause the flares which are so painful. I have
witnessed it many times in seemingly trivial situations such as where a
hot water pipe runs under a floor. Or walking on paving that has warmed
up in the sun. Not talking about barefoot on scorched ground - just
spring or autumn slight warmth.

The best floor for it is probably cool ceramic.

Perhaps you had better install underfloor refrigeration then

And forget about heating the house.



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On 26/05/2016 19:56, polygonum wrote:
On 26/05/2016 19:22, RJH wrote:
On 26/05/2016 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating. The thought of it becoming more
widespread is not pleasant.


In what way does your partner (and other users) suffer with underfloor
heating?


Severe pain in feet and legs. Seems to be moving up and also affecting
hands a bit. There are quite a number of videos - mostly poorly
presented/filmed or very individual. This is better than many:

https://www.youtube.com/watch?v=m7CTUjoHnOU


Ah I see, thanks for the explanation. Seems to be quite a small but
significant number of people affected.

I did come across UF heating as a potential issue when I used to be
involved with sheltered housing, but we could never identify any
tangible association, and from what little I understood at the time,
likely problems could be avoided/designed out in most (but obviously not
all) cases.

--
Cheers, Rob

On 26/05/2016 21:04, The Natural Philosopher wrote:
On 26/05/16 20:39, polygonum wrote:
On 26/05/2016 20:13, The Natural Philosopher wrote:

WTF has that to do with underfloor heating?

Because warm floors cause the flares which are so painful. I have
witnessed it many times in seemingly trivial situations such as where a
hot water pipe runs under a floor. Or walking on paving that has warmed
up in the sun. Not talking about barefoot on scorched ground - just
spring or autumn slight warmth.

The best floor for it is probably cool ceramic.

Perhaps you had better install underfloor refrigeration then

And forget about heating the house.



Which is what I said. But that can be problematical with respect to
condensation, etc.

--
Rod

On 26/05/2016 21:18, RJH wrote:
Ah I see, thanks for the explanation. Seems to be quite a small but
significant number of people affected.

I did come across UF heating as a potential issue when I used to be
involved with sheltered housing, but we could never identify any
tangible association, and from what little I understood at the time,
likely problems could be avoided/designed out in most (but obviously not
all) cases.

Official figures seem to be around 1:400,000 - sometimes I think it is
much higher, but often not diagnosed. Partner was only diagnosed after
telling her GP that was what it was. Followed by appointments with
several specialists who were of no help whatsoever. Eventually being
diagnosed by a dermatologist. (Actually, about 30 of them. She was asked
to attend a training session where they all came in prodded, looked,
asked questions and went off for a discussion. Unanimous.) Dermatology
is the specialty that diagnoses - but they have no idea whatsoever about
treatment.

--
Rod

Surely that would need it to be very much hotter so any flooring material
would need to be ok with this as would peoples bare feet!
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Bert Coules" wrote in message
...
Apologies for raising this venerable topic again but I do have a specific
question which I can't find answered elsewhere.

As I understand it, underfloor heating is a slow-response approach: good
for maintaining an even temperature over a long time but poor at rapidly
heating up a cold environment. But I've read in a couple of places that
recent developments in design have made it much more responsive much more
quickly.

Is that actually the case?

Many thanks.

On 27/05/16 07:46, Brian Gaff wrote:
Surely that would need it to be very much hotter so any flooring material
would need to be ok with this as would peoples bare feet!
Brian

No br8ian. Its a big area so fundamentally it doesn't have to get that
hot. Mine ran at round 25C in the open: bits covered in
carpets/dogs/settees got up towards body heat. In fact the dogs learnt
this...


--
Microsoft : the best reason to go to Linux that ever existed.

The Natural Philosopher wrote:
On 26/05/16 19:06, polygonum wrote:
On 26/05/2016 18:49, The Natural Philosopher wrote:
It remains my favourite heating system of all time. Hot air second

I have experienced underfloor heating in a few places. For myself,
maybe, but with a partner who suffers, then absolutely no way.

We now see "disabled" facilities everywhere, such as flat access, WCs
large enough for wheelchairs, etc. Some people are effectively barred
from places with underfloor heating.

Why?

The thought of it becoming more
widespread is not pleasant.


I am at a loss to understand your bigotry

I have never experienced even vaguely satisfactory warmed air heating.

Never been to a supermarket?


Our supermarkets resemble the arctic IME!

Jeff Layman wrote:

Why does the temperature fall so rapidly in the evenings in your bungalow?
With decent cavity-wall insulation and good insulation in the loft the
temperature shouldn't fall that rapidly...

The property has cavity wall insulation (installed just a few years ago) but
the loft insulation isn't good. And below the T&G floorboards and laminate
flooring there's a three foot void with the usual airbricks which must
surely be a factor.

The renovation work includes a loft conversion, so better insulation will be
incorporated there; and, whatever heating system I decide on, I plan to add
insulation under the ground floor. New ground patio doors at the rear of
the house will also presumably have better specs than the fifteen-year-old
ones they're replacing.

The present heating arrangement (whatever its setting) can't combat a very
cold zone by those rear patio doors. The new design will have such doors
across almost the whole of the back of the building: if I go for a
conventional system again I've been considering putting trench radiators
along their length. Possibly UFH (together with increased insulation) would
have the same effect, but there's no way of finding out until it's installed
and if it doesn't work it'll be a bit late to change it.

Thanks to everyone for the thoughts and suggestions.

In message , Bert
Coules writes
Jeff Layman wrote:

Why does the temperature fall so rapidly in the evenings in your
bungalow? With decent cavity-wall insulation and good insulation in
the loft the temperature shouldn't fall that rapidly...

The property has cavity wall insulation (installed just a few years
ago) but the loft insulation isn't good. And below the T&G floorboards
and laminate flooring there's a three foot void with the usual
airbricks which must surely be a factor.

Have a look at the Speedfit videos. Rigid insulation should be laid
supported by battens along the joists. Aluminium spreader plates are
secured to the joist tops and the pipes run in pre-formed grooves. Not
cheap and will still suffer from slow thermal response mentioned by
others.

Wet underfloor heating best suits 24 hour occupation.



--
Tim Lamb

Tim Lamb wrote:

Wet underfloor heating best suits 24 hour occupation.

I work from home so I suppose I fit that category. During the day I leave
the thermostat at around 20 degrees so the system doesn't kick in. If
there's a sudden drop in the temperature outside (and hence inside) I adjust
the thermostat upwards until the boiler fires.



--
Tim Lamb

Sorry, I sent that by mistake. Trying again...

Tim Lamb wrote:

Wet underfloor heating best suits 24 hour occupation.

I work from home so I suppose I fit that category, but given that I tend to
use the thermostat more like a simple on/off switch, the rapid response time
does seem to be central to want I need. Which does perhaps rule out UFH.

On 5/27/2016 8:28 AM, The Natural Philosopher wrote:
On 27/05/16 07:46, Brian Gaff wrote:
Surely that would need it to be very much hotter so any flooring material
would need to be ok with this as would peoples bare feet!
Brian

No br8ian. Its a big area so fundamentally it doesn't have to get that
hot. Mine ran at round 25C in the open: bits covered in
carpets/dogs/settees got up towards body heat. In fact the dogs learnt
this...


The underfloor heating in St Catherine's used to get quite uncomfortable
after you had been sitting on it for half an hour.

On 27/05/16 12:38, Tim Lamb wrote:
In message , Bert
Coules writes
Jeff Layman wrote:

Why does the temperature fall so rapidly in the evenings in your
bungalow? With decent cavity-wall insulation and good insulation in
the loft the temperature shouldn't fall that rapidly...

The property has cavity wall insulation (installed just a few years
ago) but the loft insulation isn't good. And below the T&G
floorboards and laminate flooring there's a three foot void with the
usual airbricks which must surely be a factor.

Have a look at the Speedfit videos. Rigid insulation should be laid
supported by battens along the joists. Aluminium spreader plates are
secured to the joist tops and the pipes run in pre-formed grooves. Not
cheap and will still suffer from slow thermal response mentioned by others.

Wet underfloor heating best suits 24 hour occupation.



*If and only if it's in-screed*

The OP mentions a suspended timber floor. If he lifts that, puts celotex
between floor joists and lays pipes between, that's a very fast response
UFH.

And will make the house a whole lot warmer anyway just from the
insulation...



--
If I had all the money I've spent on drink...
...I'd spend it on drink.

Sir Henry (at Rawlinson's End)

On 27/05/16 13:19, Bert Coules wrote:
Sorry, I sent that by mistake. Trying again...

Tim Lamb wrote:

Wet underfloor heating best suits 24 hour occupation.

I work from home so I suppose I fit that category, but given that I tend
to use the thermostat more like a simple on/off switch, the rapid
response time does seem to be central to want I need. Which does
perhaps rule out UFH.


You only need rapid response because your house is poorly insulated

Houses do not 'suddenly drop in temperature when they are well insulated


--
No Apple devices were knowingly used in the preparation of this post.

In message , Bert
Coules writes
Sorry, I sent that by mistake. Trying again...

Tim Lamb wrote:

Wet underfloor heating best suits 24 hour occupation.

I work from home so I suppose I fit that category, but given that I
tend to use the thermostat more like a simple on/off switch, the rapid
response time does seem to be central to want I need. Which does
perhaps rule out UFH.

It is normally controlled by local roomstats for each separate heated
area. A large lounge might require 2 or more lengths of piping but
controlled from one stat.

We have a modern annexe with underfloor wet heating in screed and find
the temperature does not vary much from that set.

You can use weather compensation but I think overkill for a well
insulated installation.



--
Tim Lamb

In message ,
newshound writes
On 5/27/2016 8:28 AM, The Natural Philosopher wrote:
On 27/05/16 07:46, Brian Gaff wrote:
Surely that would need it to be very much hotter so any flooring material
would need to be ok with this as would peoples bare feet!
Brian

No br8ian. Its a big area so fundamentally it doesn't have to get that
hot. Mine ran at round 25C in the open: bits covered in
carpets/dogs/settees got up towards body heat. In fact the dogs learnt
this...


The underfloor heating in St Catherine's used to get quite
uncomfortable after you had been sitting on it for half an hour.

Mother in law had a flat in one of the London Barbican developments.
That was underfloor electric which I found very uncomfortable. I'm not
sure if they used the floor thermal mass and economy 7 or some other
arrangement. It was not in the control of the occupier:-(

--
Tim Lamb

Tim Lamb wrote:.

It is normally controlled by local roomstats for each separate heated
area. A large lounge might require 2 or more lengths of piping but
controlled from one stat.

Thanks for that. The overall footprint of the bungalow is a simple
rectangle. The ground floor - currently the only floor - is completely open
plan except for the bathroom, which cuts into one side of the space: broadly
speaking the living area is in the shape of a very thick capital letter E
with the central horizontal line missing. If it's practical, I suppose that
could constitute two zones, one for the living area, another for the
bathroom.

The new first floor will be essentially similar, so another two zones,
perhaps.

What is the absolute minimum thickness required by UFH? As planned, the
headroom on the new first floor is not generous: 2060mm on the drawings.

On 27/05/2016 09:38, Capitol wrote:

Our supermarkets resemble the arctic IME!

They do tend to have some areas which are dreadfully cold.

Many years ago, one of the supermarkets I used had a walk-through cool
room section for dairy. Seemed quite a good idea but only seen it (so
far as I remember) in two shops.

As the context is uk.d-i-y, and the topic was domestic underfloor
heating, suddenly switching to large commercial premises was quite a
jump. Still largely true - few supermarkets have good heating/cooling -
tends to be too hot, too cold, too much draught, or too noisy. Even if
it passed all those criteria, the stink from the bakery, pig cookery,
chicken burner, etc., which will often fill the entire store,
exemplifies why too much recycling of air round a building can be a bad
idea.

--
Rod

On 27/05/2016 17:35, Tim Lamb wrote:

Mother in law had a flat in one of the London Barbican developments.
That was underfloor electric which I found very uncomfortable. I'm not
sure if they used the floor thermal mass and economy 7 or some other
arrangement. It was not in the control of the occupier:-(

From a similar era, our school library had electric underfloor heating.
On some form of night tariff. Baking in the morning - windows wide open
to let that excess heat out. Cool in the middle of the day. By end of
afternoon, could be freezing.

--
Rod

On 27/05/16 18:07, Bert Coules wrote:
Tim Lamb wrote:.

It is normally controlled by local roomstats for each separate heated
area. A large lounge might require 2 or more lengths of piping but
controlled from one stat.

Thanks for that. The overall footprint of the bungalow is a simple
rectangle. The ground floor - currently the only floor - is completely
open plan except for the bathroom, which cuts into one side of the
space: broadly speaking the living area is in the shape of a very thick
capital letter E with the central horizontal line missing. If it's
practical, I suppose that could constitute two zones, one for the living
area, another for the bathroom.

The new first floor will be essentially similar, so another two zones,
perhaps.

What is the absolute minimum thickness required by UFH?

Thickness of what?


As planned, the
headroom on the new first floor is not generous: 2060mm on the drawings.


I found that with UFH on ground floor, first floor without extra heating
was a nice 3 degrees cooler.

20C ground in winter, 17C bedrooms..






--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin

"The Natural Philosopher" wrote:

Thickness of what?

Thickness of the whole installation. If the designed (bare chipboard) floor
to ceiling height is 2060mm, how much will that be reduced by UFH?

...20C ground in winter, 17C bedrooms.

Personally, I don't care to have a bedroom that's cooler than the rest of
the house. I find that distinctly uncomfortable.

On 27/05/16 20:37, Bert Coules wrote:
"The Natural Philosopher" wrote:

Thickness of what?

Thickness of the whole installation. If the designed (bare chipboard) floor
to ceiling height is 2060mm, how much will that be reduced by UFH?

It can be very thin for the heating elements themselves:
https://www.tlc-direct.co.uk/Main_In...ing/index.html

or a bit thicker:
https://www.tlc-direct.co.uk/Main_In...Mat/index.html

It all depends on how much insulation you have/want under the heating
elements. I hadn't noticed you mention an upper floor before, just a
single floor in a bungalow. Do you intend putting insulation under the
tiles to keep the first floor warm?

FWIW, I have the first type of UFH (for laminate flooring) in a
conservatory. It is on a screed floor over 50 mm Celotex and It can't
keep the temperature at a comfortable level on a cold day less than 5
deg C outside or a not-so-cold day when it's windy,. So if needed, a fan
heater has to be used as well. It is also bloody expensive to run.

...20C ground in winter, 17C bedrooms.

Personally, I don't care to have a bedroom that's cooler than the rest of
the house. I find that distinctly uncomfortable.

Nor do I. But with an additional floor, much of your ground-floor heat
will disappear upstairs unless there is a door between the ground and
first floor. Any bedroom up there might well be warmer than the ground
floor! With warm-air heating, it might be possible to recirculate the
warm air which collects at the top of the building, so saving on heating
and reducing temperature differences throughout the living areas. I
don't know as I have not looked into that possibility. Don't "passive"
houses use that sort of thing?

--

Jeff

In message , Bert
Coules writes
Tim Lamb wrote:.

It is normally controlled by local roomstats for each separate heated
area. A large lounge might require 2 or more lengths of piping but
controlled from one stat.

Thanks for that. The overall footprint of the bungalow is a simple
rectangle. The ground floor - currently the only floor - is completely
open plan except for the bathroom, which cuts into one side of the
space: broadly speaking the living area is in the shape of a very thick
capital letter E with the central horizontal line missing. If it's
practical, I suppose that could constitute two zones, one for the
living area, another for the bathroom.

You can run the heating water through a towel rail. I'm told!

The new first floor will be essentially similar, so another two zones,
perhaps.

What is the absolute minimum thickness required by UFH? As planned,
the headroom on the new first floor is not generous: 2060mm on the
drawings.

The laid over, pre-formed insulation is 25mm thick and is pre-grooved to
take the pipe. Your flooring goes on top 18-22mm chip?

Otherwise, the fix from top system goes between the joists prior to
laying the floor and does not raise the floor.







--
Tim Lamb

On 28/05/16 08:52, Tim Lamb wrote:
In message , Bert
Coules writes
Tim Lamb wrote:.

It is normally controlled by local roomstats for each separate heated
area. A large lounge might require 2 or more lengths of piping but
controlled from one stat.

Thanks for that. The overall footprint of the bungalow is a simple
rectangle. The ground floor - currently the only floor - is
completely open plan except for the bathroom, which cuts into one side
of the space: broadly speaking the living area is in the shape of a
very thick capital letter E with the central horizontal line missing.
If it's practical, I suppose that could constitute two zones, one for
the living area, another for the bathroom.

You can run the heating water through a towel rail. I'm told!

The new first floor will be essentially similar, so another two zones,
perhaps.

What is the absolute minimum thickness required by UFH? As planned,
the headroom on the new first floor is not generous: 2060mm on the
drawings.

The laid over, pre-formed insulation is 25mm thick and is pre-grooved to
take the pipe. Your flooring goes on top 18-22mm chip?

If you have just an inch of insulation underneath you will lose a LOT of
heat downwards.

You MUST insulate under the floating floor with full 60-90mm of celotex

25 mm is fine for upstairs though



Otherwise, the fix from top system goes between the joists prior to
laying the floor and does not raise the floor.









--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin

On 27/05/2016 13:11, Bert Coules wrote:
Tim Lamb wrote:

Wet underfloor heating best suits 24 hour occupation.

I work from home so I suppose I fit that category. During the day I
leave the thermostat at around 20 degrees so the system doesn't kick
in. If there's a sudden drop in the temperature outside (and hence
inside) I adjust the thermostat upwards until the boiler fires.


Underfloor heating with each room on it's own zone so each room has it's
own programmable thermostat that you can set fallback (day/night
un-occupied) temperature to depending on room usage. So office(?) set to
20 degrees and all others set to 18 degrees.

Bedrooms on a 2nd circuit but radiators with TRV's rather than UFH
So you have 2 system programmers or you could use a single programmer
and use the H/W settings for bedrooms if you don't have H/W storage.

Our living rooms have very little thermal mass as the UFH is between
floor joists with about 15cm of a sand/cement skim that I put in to
provide a degree of heat spread also cheaper than aluminium spreader
plates and I was concerned about spreader plates causing
expansion/contraction noises at the time. Be aware you might need to
re-run/re-wire at the same time as cables may be pulled through centre
of joists which in my case was about an inch too high in some places.

It doesn't have a "rapid" response but now the house never cools down
enough to cause a problem.

Having had no loft insulation for a few years after fitting UFH we had
to have a halogen heater in the front room but after insulating I was
able to drop the system temp to 50 degrees Max. and it's ample although
because the boiler has weather compensation it's constantly changing
flow temp based on outside temperature so a sudden drop in temperature
can take the house around 36 hours to balance it's self again.

Beauty of weather compensation is the heating is never switched off. The
boiler just won't run if the outside temp has reached a defined
temperature e.g. 20 degrees and if it's say... 16 degrees the water
might be circulating at less than 3 degrees which is perfect for both
the UFH and the radiators.

Most important thing is having insulation up to spec. That way the
heating will never need to heat from cold and you'll never need to worry
about switching off the heating is you go away for a week.
Or you could always lower the set-back temp to 16 degrees but for the
few £ you'll save (if that) it's not worth it.

HTH
Cheers - Pete

On 28/05/16 09:36, Pet @ www.gymratz.co.uk ;¬) wrote:
Most important thing is having insulation up to spec. That way the
heating will never need to heat from cold and you'll never need to worry
about switching off the heating is you go away for a week.

And that is the issue.

If you have poor insulation sticking the heat next to the cold hard
ground will waste huge amounts of it.

In a reasonably well insulated setup I found 50W/square meter adequate,
100W/sq meter capable of fast warm up to insane temperatures (if not
controlled).

You have to remember that a thick insulated fitted carpet is fine as an
insulator over a concrete floor slab with radiators, but its not usable
over UFH.


IN all cases you have to understand the house design in totality.

There is no 'UFH is good/bad/fast/slow' etc etc.

Id definitely use it again, but I'd be even MORE careful about
insulation design this time.




--
A lie can travel halfway around the world while the truth is putting on
its shoes.