Calculating BTUs from radiator size
 

Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Thanks

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 09:00:47 +0100 someone who may be DIY-Not
wrote this:-

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Look up the catalogue for any manufacturer and you should find a
similar sized and arranged radiator. Look up the nominal output in
kW and you have a figure.

You will probably find you need a very large towel drier to provide
an equivalent output.

It is generally best to separate heating the room from drying
towels.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Calculating BTUs from radiator size
 

On 2007-09-10 09:00:47 +0100, DIY-Not said:

Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Thanks

It is better not to use BTUs at all. This is an old unit of
measurement, with Watts being the thing to use to avoid getting mixing
of units and consequent errors.


The approach is to look at radiator manufacturer web sites for
radiators that look as close as possible to yours. Most important is
to look for the number of panels and whether or not there are fins
since these make the most difference to output. You hould be able
to determine a figure in Watts.

Armed with that, you can identify a towel radiator. However, this
will be challenging, since this is quite a large radiator that you
have. Towel radiators don't have much output anyway and it will be
insulated with towels.

Calculating BTUs from radiator size
 

DIY-Not wrote:

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Not really feasible as it depends on many factors - eg a modern radiator
is likely to be much more efficient than an older but similar-sized
radiator. Better to calculate the requirements from first principles.

David

Calculating BTUs from radiator size
 

In an earlier contribution to this discussion,
DIY-Not DIY-Not wrote:

Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Thanks

I've just been through an exercise of re-calculating my heat losses and
estimating the output of my radiators in order to do a sanity check on my
system. Most of my radiators are single or double panel unfinned ones, which
are not too common these days - so not easy to find current catalogues of
similar ones for the purpose of finding the heat output. I have, however,
got some historical information from when I installed a system in my
previous house in about 1970, and have converted that from BTU/Hr into
Watts.

The rule of thumb which I have been using for single panel unfinned rads is
1280 Watts per M^2 (of projected area rather than total surface area) at a
Delta-T [1] of 60 degC. On that basis, your radiator would have an output of
about 645 Watts. You may struggle to get a towel radiator with this sort of
output because they necessarily have far less surface area than a normal
radiator size for size.

[1] Delta-T is the temperature difference between the room and the mean rad
temperature. Your system probably runs at less than 60 degC difference, in
which case the radiator output will be less. If you compare it with another
one which is also rated for a Delta-T of 60degC, it doesn't matter. If you
compare it with one specified at a lower Delta-T, you need to allow for
that. For example, your rad would be worth about 515 Watts rather than 645
at a Delta-T of 50 degC.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"
wrote:



I've just been through an exercise of re-calculating my heat losses and
estimating the output of my radiators in order to do a sanity check on my
system. Most of my radiators are single or double panel unfinned ones, which
are not too common these days - so not easy to find current catalogues of
similar ones for the purpose of finding the heat output. I have, however,
got some historical information from when I installed a system in my
previous house in about 1970, and have converted that from BTU/Hr into
Watts.

The rule of thumb which I have been using for single panel unfinned rads is
1280 Watts per M^2 (of projected area rather than total surface area) at a
Delta-T [1] of 60 degC. On that basis, your radiator would have an output of
about 645 Watts. You may struggle to get a towel radiator with this sort of
output because they necessarily have far less surface area than a normal
radiator size for size.

[1] Delta-T is the temperature difference between the room and the mean rad
temperature. Your system probably runs at less than 60 degC difference, in
which case the radiator output will be less. If you compare it with another
one which is also rated for a Delta-T of 60degC, it doesn't matter. If you
compare it with one specified at a lower Delta-T, you need to allow for
that. For example, your rad would be worth about 515 Watts rather than 645
at a Delta-T of 50 degC.

Thanks Roger, this is very useful. My rads are 20+ years old,
unfinned, so probably not as efficient as modern designs.. It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 10:39:13 +0100, wrote:

On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"
wrote:


snipped

Thanks Roger, this is very useful. My rads are 20+ years old, unfinned, so
probably not as efficient as modern designs.. It is possible to get a
towel rad with this sort of output but with adding a bit on try and
compensate a bit for the insulation of the towels I'm looking at a rad of
about 1500mm x 600mm. This is for a white one, can't find a chromed one
near big enough. At this size it's probably going to dominate the room too
much, so maybe time for a rethink on the project.

==================================
Cheap and cheerful - quite effective:

http://www.argos.co.uk/static/Produc...er/8504405.htm

Cic.

--
===================================
Using Ubuntu Linux
Windows shown the door
===================================

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 09:48:57 GMT, Cicero
wrote:

On Mon, 10 Sep 2007 10:39:13 +0100, wrote:

On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"
wrote:


snipped

Thanks Roger, this is very useful. My rads are 20+ years old, unfinned, so
probably not as efficient as modern designs.. It is possible to get a
towel rad with this sort of output but with adding a bit on try and
compensate a bit for the insulation of the towels I'm looking at a rad of
about 1500mm x 600mm. This is for a white one, can't find a chromed one
near big enough. At this size it's probably going to dominate the room too
much, so maybe time for a rethink on the project.

==================================
Cheap and cheerful - quite effective:

http://www.argos.co.uk/static/Produc...er/8504405.htm

Cic.

It doesn't appear to be available in designer chrome ??

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 11:04:53 +0100, wrote:

On Mon, 10 Sep 2007 09:48:57 GMT, Cicero wrote:

On Mon, 10 Sep 2007 10:39:13 +0100, wrote:

On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"
wrote:


snipped

Thanks Roger, this is very useful. My rads are 20+ years old, unfinned,
so probably not as efficient as modern designs.. It is possible to get
a towel rad with this sort of output but with adding a bit on try and
compensate a bit for the insulation of the towels I'm looking at a rad
of about 1500mm x 600mm. This is for a white one, can't find a chromed
one near big enough. At this size it's probably going to dominate the
room too much, so maybe time for a rethink on the project.

==================================
Cheap and cheerful - quite effective:

http://www.argos.co.uk/static/Produc...er/8504405.htm

Cic.

It doesn't appear to be available in designer chrome ??

===================================
Try 'googling'. They are available in (designer)chrome - I've got three,
but I've had them quite a long time so can't give you a source.

Cic.

--
===================================
Using Ubuntu Linux
Windows shown the door
===================================

Calculating BTUs from radiator size
 

On 10 Sep, 10:39, DIY-Not wrote:
On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"



wrote:

I've just been through an exercise of re-calculating my heat losses and
estimating the output of my radiators in order to do a sanity check on my
system. Most of my radiators are single or double panel unfinned ones, which
are not too common these days - so not easy to find current catalogues of
similar ones for the purpose of finding the heat output. I have, however,
got some historical information from when I installed a system in my
previous house in about 1970, and have converted that from BTU/Hr into
Watts.

The rule of thumb which I have been using for single panel unfinned rads is
1280 Watts per M^2 (of projected area rather than total surface area) at a
Delta-T [1] of 60 degC. On that basis, your radiator would have an output of
about 645 Watts. You may struggle to get a towel radiator with this sort of
output because they necessarily have far less surface area than a normal
radiator size for size.

[1] Delta-T is the temperature difference between the room and the mean rad
temperature. Your system probably runs at less than 60 degC difference, in
which case the radiator output will be less. If you compare it with another
one which is also rated for a Delta-T of 60degC, it doesn't matter. If you
compare it with one specified at a lower Delta-T, you need to allow for
that. For example, your rad would be worth about 515 Watts rather than 645
at a Delta-T of 50 degC.

Thanks Roger, this is very useful. My rads are 20+ years old,
unfinned, so probably not as efficient as modern designs.. It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

You don't state the size of the bathroom/showerroom you've got which
would help us. My bathroom is near enough 2m x 4 and is heated by one
10 plate heater a bit like this from Screwfix but 75mm wide plates.

http://www.screwfix.com/app/sfd/cat/...79837&ts=22101

I don't know what it's heat output is but it acts well as a towel
drier and room warmer. To back it up there's a pull cord fan heater -
viz

http://www.tlc-direct.co.uk/Main_Ind...Fan_Heaters_3/

which was put in for my wife's benefit only !

Rob

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 04:10:30 -0700, robgraham
wrote:

On 10 Sep, 10:39, DIY-Not wrote:
On Mon, 10 Sep 2007 10:23:17 +0100, "Roger Mills"



wrote:

I've just been through an exercise of re-calculating my heat losses and
estimating the output of my radiators in order to do a sanity check on my
system. Most of my radiators are single or double panel unfinned ones, which
are not too common these days - so not easy to find current catalogues of
similar ones for the purpose of finding the heat output. I have, however,
got some historical information from when I installed a system in my
previous house in about 1970, and have converted that from BTU/Hr into
Watts.

The rule of thumb which I have been using for single panel unfinned rads is
1280 Watts per M^2 (of projected area rather than total surface area) at a
Delta-T [1] of 60 degC. On that basis, your radiator would have an output of
about 645 Watts. You may struggle to get a towel radiator with this sort of
output because they necessarily have far less surface area than a normal
radiator size for size.

[1] Delta-T is the temperature difference between the room and the mean rad
temperature. Your system probably runs at less than 60 degC difference, in
which case the radiator output will be less. If you compare it with another
one which is also rated for a Delta-T of 60degC, it doesn't matter. If you
compare it with one specified at a lower Delta-T, you need to allow for
that. For example, your rad would be worth about 515 Watts rather than 645
at a Delta-T of 50 degC.

Thanks Roger, this is very useful. My rads are 20+ years old,
unfinned, so probably not as efficient as modern designs.. It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

You don't state the size of the bathroom/showerroom you've got which
would help us. My bathroom is near enough 2m x 4 and is heated by one
10 plate heater a bit like this from Screwfix but 75mm wide plates.

http://www.screwfix.com/app/sfd/cat/...79837&ts=22101

I don't know what it's heat output is but it acts well as a towel
drier and room warmer. To back it up there's a pull cord fan heater -
viz

http://www.tlc-direct.co.uk/Main_Ind...Fan_Heaters_3/

which was put in for my wife's benefit only !

Rob

My bathroom is 2.3m x 3.2m with one outside wall, double glazed, and
plenty of roof insulation. So do you find you need to use the fan
heater much?

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 10:39:13 +0100 someone who may be DIY-Not
wrote this:-

It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

Is there space to fit a small water filled towel rail. These can be
fed off the central heating and provided with an electric element
for use when the heating is not turned on.

Alternately use solar water heating and in the summer use a little
of the hot water for the towel rail.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Calculating BTUs from radiator size
 

On Mon, 10 Sep 2007 13:09:29 +0100, David Hansen
wrote:

On Mon, 10 Sep 2007 10:39:13 +0100 someone who may be DIY-Not
wrote this:-

It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

Is there space to fit a small water filled towel rail. These can be
fed off the central heating and provided with an electric element
for use when the heating is not turned on.

Alternately use solar water heating and in the summer use a little
of the hot water for the towel rail.

Note that SS bathroom rads have a much higher output than chrome
plated ones.

If your bath is steel you could hide a radiator underneath (and
possibly in contact with) the bath.
Robert

Calculating BTUs from radiator size
 

On 2007-09-10 14:53:29 +0100, lid said:

On Mon, 10 Sep 2007 13:09:29 +0100, David Hansen
wrote:

On Mon, 10 Sep 2007 10:39:13 +0100 someone who may be DIY-Not
wrote this:-

It is
possible to get a towel rad with this sort of output but with adding a
bit on try and compensate a bit for the insulation of the towels I'm
looking at a rad of about 1500mm x 600mm. This is for a white one,
can't find a chromed one near big enough. At this size it's probably
going to dominate the room too much, so maybe time for a rethink on
the project.

Is there space to fit a small water filled towel rail. These can be
fed off the central heating and provided with an electric element
for use when the heating is not turned on.

Alternately use solar water heating and in the summer use a little
of the hot water for the towel rail.

Note that SS bathroom rads have a much higher output than chrome
plated ones.

If your bath is steel you could hide a radiator underneath (and
possibly in contact with) the bath.
Robert

They do - I recently checked this point.


However, this is still small in comparison with a panel radiator
especially if covered in towels.

Calculating BTUs from radiator size
 

In article ,
DIY-Not writes:
Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Assume the output of the towel rail is zero, which it pretty much
is when it's got towels on it. The rating published is with no
covering, which is not how towel rails are used. Thus you probably
don't want to get rid of your radiator when you add a towel rail.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Calculating BTUs from radiator size
 

On 10 Sep 2007 17:58:03 GMT, (Andrew
Gabriel) wrote:

In article ,
DIY-Not writes:
Hi

I'm replacing a single panel radiator with a towel radiator. So I can
select the correct size of towel rad I need to calculate the BTU
output from the original. The original rad is 730mm x 690mm and keeps
the room nice and toasty.

Is there an approximate calculation for this?

Assume the output of the towel rail is zero, which it pretty much
is when it's got towels on it. The rating published is with no
covering, which is not how towel rails are used. Thus you probably
don't want to get rid of your radiator when you add a towel rail.
If you've just splashed out on an expensive designer towel rad the
last thing you want to do is cover it up with towels. !
Robert