Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation. Of course, the many pipe entries meant it was not easy to
line up the edges of the bags, and I had to cut a hole for the cylinder
thermostat, as the instructions say it should not be covered.

After fiddling around and making sure it wasn't covered, I wondered why
it shouldn't be covered. Surely it doesn't make any difference if it's
covered of not if it's on contact with the metal of the tank.

Oh, and the cylinder insulation doesn't seem to be designed for
top-entry immersion heaters (which we have) as much of the insulating
action seems to rely on the top of the tank being covered completely
with overlapping edges. I had to ensure the immersion heater and
connecting cable wasn't covered.

--

Jeff

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation. Of course, the many pipe entries meant it was not easy to
line up the edges of the bags, and I had to cut a hole for the cylinder
thermostat, as the instructions say it should not be covered.

Mine is an old bi-metal type with a knob on the front to set the
temperature (in deg F)

--

Graham.
%Profound_observation%

Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

"Chris J Dixon" wrote in message
...
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Not really possible to do the maths in isolation.

You'd have to actually measure how quickly it cools
with the electricity turned off, with and without the
extra insulation, to see how long it would take to
pay for itself and if it actually would.

On Tuesday, 25 September 2018 19:38:58 UTC+1, Chris J Dixon wrote:
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Chris

results depend heavily on what airgaps are left, and those are hard to control.


nt

On Wed, 26 Sep 2018 04:49:13 +1000, 543dsa, better known as cantankerous
trolling senile geezer Rot Speed, wrote:


With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Not

LOL

Have you EVER wondered why almost EVERY single post of yours starts either
with "not" or "nope", you abnormal senile "argumentative asshole"?

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On 25/09/2018 19:49, 543dsa wrote:


"Chris J Dixon" wrote in message
...
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)

over a hot water cylinder which already had about 25mm ofÂ* foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Not really possible to do the maths in isolation.

You'd have to actually measure how quickly it cools
with the electricity turned off, with and without the
extra insulation, to see how long it would take to
pay for itself and if it actually would.

wrong as usual

its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

"dennis@home" wrote in message
...
On 25/09/2018 19:49, 543dsa wrote:


"Chris J Dixon" wrote in message
...
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

I might well try to do the same, if there is any significant
benefit.

Not really possible to do the maths in isolation.

You'd have to actually measure how quickly it cools
with the electricity turned off, with and without the
extra insulation, to see how long it would take to
pay for itself and if it actually would.

wrong as usual

We'll see...

its quite easy to do the maths.

Not when you dont have the numbers to use.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

Pity that that doesnt tell you the actual u value
of the original tank, or the added blanket given
the impossibility of allowing for how well it is
fitted around the pipes and thermostat etc.

dennis@home wrote:
its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
+25mm of polyurethane: U=0.85
+80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306 kWh/year
+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
+80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

- adding the jacket saves 321 kWh/year of gas, at 4p/unit about GBP12.84.
(+combustion losses)

So it'll payback in 9 months - assuming you keep the water hot all day.

Theo

On Wed, 26 Sep 2018 06:53:07 +1000, 543dsa, better known as cantankerous
trolling senile geezer Rot Speed, wrote:


wrong as usual

We'll see...

Everyone will see again what a self-opinionated, pathological, senile
asshole you are, Rot!

--
Bill Wright addressing senile Ozzie cretin Rot Speed:
"Well you make up a lot of stuff and it's total ******** most of it."
MID:

"Theo" wrote in message
...
dennis@home wrote:
its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
+25mm of polyurethane: U=0.85
+80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306 kWh/year
+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
+80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

The problem is getting a real figure for the added insulation.
That number is plucked out of the air, its not the real figure.

- adding the jacket saves 321 kWh/year of gas, at 4p/unit about GBP12.84.
(+combustion losses)

So it'll payback in 9 months - assuming you keep the water hot all day.

Don’t buy that with real commercial storage hot water
tanks and its never 20C outside all year round anyway.

On Tuesday, 25 September 2018 22:37:30 UTC+1, Theo wrote:
dennis@home wrote:
its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
+25mm of polyurethane: U=0.85
+80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306 kWh/year
+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
+80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

- adding the jacket saves 321 kWh/year of gas, at 4p/unit about GBP12.84.
(+combustion losses)

So it'll payback in 9 months - assuming you keep the water hot all day.

Theo

last time I looked at a jacketed cylinder there were gaps all over the place. ROI is thus much worse, but by how much I couldn't say.


NT

On Wednesday, 26 September 2018 03:51:17 UTC+1, wrote:
last time I looked at a jacketed cylinder there were gaps all over
the place. ROI is thus much worse, but by how much I couldn't say.

For under a tenner, and with bank interest rates so low, it's hardly a big decision.

Owain

On 26/09/2018 01:11, 543dsa wrote:


"Theo" wrote in message
...
dennis@home wrote:
its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
*+25mm of polyurethane: U=0.85
** +80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306 kWh/year
*+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
** +80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

The problem is getting a real figure for the added insulation.
That number is plucked out of the air, its not the real figure.


It is based on a set of reasonable assumptions so far as I can see. It's
called modelling . . .

- adding the jacket saves 321 kWh/year of gas, at 4p/unit about GBP12.84.
(+combustion losses)

So it'll payback in 9 months - assuming you keep the water hot all day.


A lot quicker if the immersion is used regularly.

Don’t buy that with real commercial storage hot water
tanks and its never 20C outside all year round anyway.

I think the context here is domestic tanks indoors.

A business that stores hot water outside in an uninsulated tank isn't
going to last long enough to even begin to discuss insulation.

--
Cheers, Rob

"RJH" wrote in message
news
On 26/09/2018 01:11, 543dsa wrote:


"Theo" wrote in message
...
dennis@home wrote:
its quite easy to do the maths.

its done the same as electrical resistance.

however its easier to use something like

www.vesma.com/tutorial/uvalue01/uvalue01.htm

OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
+25mm of polyurethane: U=0.85
+80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306
kWh/year
+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
+80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

The problem is getting a real figure for the added insulation.
That number is plucked out of the air, its not the real figure.


It is based on a set of reasonable assumptions so far as I can see. It's
called modelling . . .

Not possible to model the real life U value of the
added insulation given that it has to have the
pipes and overflow relief valve going through it.

Sure, you can certainly use worst case numbers
but even with the external temperature, it isnt
really that easy to actually measure what that
is over the whole of an average year etc.

As I said initially, it makes a lot more sense to
actually measure the reduced loss with the
heater turned off, with and without the extra
insulation, but you do have to buy it to test it.

- adding the jacket saves 321 kWh/year of gas, at 4p/unit about
GBP12.84.
(+combustion losses)

So it'll payback in 9 months - assuming you keep the water hot all day.


A lot quicker if the immersion is used regularly.

How often it is used has no effect on the payback period.
What is being calculated is the loss from the cylinder that
is saved with the extra insulation and how long it takes
to pay for the extra insulation.

Don’t buy that with real commercial storage hot water
tanks and its never 20C outside all year round anyway.

I think the context here is domestic tanks indoors.

Yes, but that doesn’t make it any easier to calculate.

A business that stores hot water outside in an uninsulated tank isn't
going to last long enough to even begin to discuss insulation.

Sure. But we arent talking about uninsulated tanks, we
are talking about insulated tanks and whether EXTRA
insulation like the one in the url will pay for themselves.

And plenty of domestic tanks are outdoors,
because that doesn’t waste space indoors.

On 25/09/2018 20:22, wrote:


results depend heavily on what airgaps are left, and those are hard to control.


On jackets I've fitted here have been minimal air gaps especially none
at the top of the cylinder where the panels overlap giving a thicker layer.

There is a table at
https://www.thegreenage.co.uk/insula...r-tank-jacket/

which suggests payback of less than 1 year in the OPs case were he had
25mm of existing foam insulation. The table figures assume the jacket
cost £25 but the OP paid £10 so their 2 year figure needs to be reduced.


--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 25/09/2018 19:38, Chris J Dixon wrote:
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)
over a hot water cylinder which already had about 25mm of foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

Depends how much you have already but as a rough rule of thumb if you
doubled the thickness using the same material then the rate of heat loss
through it would he halved. However, conduction along pipes in and out
of the hot zone make it somewhat less effective than that.

I might well try to do the same, if there is any significant
benefit.

£30 spent on better insulation round the hot water tank pays for itself
with the fuel savings in the first year. It also means that your hot
water stays warmer for longer when the heating isn't on.

--
Regards,
Martin Brown

On Wed, 26 Sep 2018 10:11:00 +1000, 543dsa, better known as cantankerous
trolling senile geezer Rot Speed, wrote:


OK, let's try:

Hot water cylinder 450mm dia, 1.2m tall (first one on Screwfix)
pi*d*l = 3.14*0.45*1.2 = 1.7 sqm

According to the calculator, a 'wall' with 60C inside and 20C outside:

Uninsulated (1mm of steel): U=5.55 W/m^2 K
+25mm of polyurethane: U=0.85
+80mm of glassfib U=0.31

deltaT = 60-20 = 40
Uninsulated, power transfer ('loss') = 1.7*5.55*40 = 377W = 3306 kWh/year
+25mm PU = 1.7*0.85*40 = 57.8W = 506 kWh/year
+80mm GF = 1.7*0.31*40 = 21.1W = 185 kWh/year

The problem is getting a real figure for the added insulation.
That number is plucked out of the air, its not the real figure.

LOL Senile Rot knows it BETTER ...AGAIN!

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On Wed, 26 Sep 2018 17:49:36 +1000, 543dsa, better known as cantankerous
trolling senile geezer Rot Speed, wrote:




It is based on a set of reasonable assumptions so far as I can see. It's
called modelling . . .

Not

LOL! He said it again, the notorious "argumentative asshole"!

--
Bill Wright to Rot Speed:
"That confirms my opinion that you are a despicable little ****."
MID:

"543dsa" Wrote in message:


And plenty of domestic tanks are outdoors,
because that doesn?t waste space indoors.


Um, in the UK? Seen it plenty of times in Spain and other warm
countries, never in the UK.

Tim


--

On 26/09/2018 09:50, Martin Brown wrote:
On 25/09/2018 19:38, Chris J Dixon wrote:
Jeff Layman wrote:

Just fitted some insulation
(https://www.screwfix.com/p/hot-water-cylinder-jacket-18-x-80mm-x-1219mm/43483)

over a hot water cylinder which already had about 25mm ofÂ* foam
insulation.

With existing tank insulation, can anybody do the maths to work
out how much difference the extra lagging will make?

Depends how much you have already but as a rough rule of thumb if you
doubled the thickness using the same material then the rate of heat loss
through it would he halved. However, conduction along pipes in and out
of the hot zone make it somewhat less effective than that.

I might well try to do the same, if there is any significant
benefit.

£30 spent on better insulation round the hot water tank pays for itself
with the fuel savings in the first year. It also means that your hot
water stays warmer for longer when the heating isn't on.

Worth keeping in mind that if you have the cylinder in an airing
cupboard, you may actually want some heat loss to heat the cupboard.


--
Cheers,

John.

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

On 26/09/2018 11:24, John Rumm wrote:
On 26/09/2018 09:50, Martin Brown wrote:
On 25/09/2018 19:38, Chris J Dixon wrote:

I might well try to do the same, if there is any significant
benefit.

£30 spent on better insulation round the hot water tank pays for
itself with the fuel savings in the first year. It also means that
your hot water stays warmer for longer when the heating isn't on.

Worth keeping in mind that if you have the cylinder in an airing
cupboard, you may actually want some heat loss to heat the cupboard.

Fair point but I doubt if you could insulate a tank in such a cupboard
well enough to cause a problem. Not a lot of room in the ones I've seen.

--
Regards,
Martin Brown