Electric immersion water cylinder: jacket?

k_man

As above, as already insulated, extra insulation will add little benefit.
Most heat loss will be from the hot water pipes coming out, rather than the tank itself.

I was imagining something like this 😁:

https://www.thegreenage.co.uk/wp-content/uploads/2014/04/Hot-water-tank-not-insulated.jpg

[Deleted User]

Hi,

from HEATRAE, looks like it has this insulation,

60mm of CFC / HCFC-free injected foam for the best possible heat retention and energy efficiency

xeny

There's a thread here https://lemonfool.co.uk/viewtopic.php?f=14&t=35513 albeit discussing a foam sprayed cylinder which concludes lagging is worthwhile.

My feeling is that if the cupboard is significantly warm then enough heat is escaping that a cheap jacket is probably worthwhile, as is insulating any exposed hot water pipework associated with the cylinder. Given likely energy costs, payback on £15 or so of insulation is going to be short if it makes pretty much any difference.

k_man

Interestingly that discussion starts with the following, so not quite the same scenario:

an old, 1980s(ish) hot water cyl lagged with a foam sprayed on to it. It is about 30mm thick. A couple of showers or a bath emptied the cyl, and after 24 hours away the water was pretty much cold, compared to the previous house with a well insulated megaflo which could keep it warm for 3 days.

chris_n

Whatever you do don't insulate where the immersion heaters are.

[Deleted User]

Hi,

you could insulate pipes with some of this stuff,

littleteapot

frugalmacdugal said:

Hi,

you could insulate pipes with some of this stuff,

Yes that is the best thing to do given the OP already has a modern, well insulated cylinder.

I replaced our old foam-coated copper cylinder a few years ago with a similar type to the OP's (mine is a Gledhill Stainless Lite) and there was very little heat loss from the cylinder itself. But the  pipes remained hot for at least 3 feet from the cylinder, even if no water had been drawn off for hours, which was keeping the cupboard quite warm still. So I fitted the thick type of laggging (as per the two right samples in the above photo) to all the pipes up to the point they exit the cupboard and that made a huge difference to the temperature inside the cupboard.

In addition to that the water remains useably warm for up to 2 whole days now.

EssexHebridean

I've been reading this thread (and the one linked to) with interest as further lagging on the cylinder is something I've been considering for a while now. It's a balance though - our cylinder is literally right in the middle of the property so we absolutely DO get benefit from the heat leakage - less of an advantage at this time of year obviously, but in the winter it must make a difference. I'm still undecided - although I want to see how we go for a little while longer yet with our "just use it less" experiment. 

matelodave

The heat loss from a cylinder like that is pretty low and wrapping it in an old duvet might reduce it but not by much, however the loss from the pipework around it  can be quite high. so get some pipe insulation as @frugalmacdugal suggests.

We did have an airing cupboard in a previous house where I put a board across the doorway in front of the tank and filled the whole void with polystyrene packing granules to insulate it.

Our present tank, in the utility room, is fully insulated like yours and we've insulated both the hot and cold pipework connected to it. The hot to keep the heat in and the cold to reduce condensation. We also don't keep it everso hot, around 45 degrees which also reduces the heat loss.

sebtomato

littleteapot said:

frugalmacdugal said:

Hi,

you could insulate pipes with some of this stuff,

Yes that is the best thing to do given the OP already has a modern, well insulated cylinder.

I replaced our old foam-coated copper cylinder a few years ago with a similar type to the OP's (mine is a Gledhill Stainless Lite) and there was very little heat loss from the cylinder itself. But the  pipes remained hot for at least 3 feet from the cylinder, even if no water had been drawn off for hours, which was keeping the cupboard quite warm still. So I fitted the thick type of laggging (as per the two right samples in the above photo) to all the pipes up to the point they exit the cupboard and that made a huge difference to the temperature inside the cupboard.

In addition to that the water remains useably warm for up to 2 whole days now.

I think that's right. The cylinder is not that warm when touching it (even in the morning, after water has been heated), but the warm water pipe exiting from the top is indeed quite hot. None of the pipes are insulated, all copper.

I guess that would explain why the cupboard is quite warm.

I shall try some lagging on the pipes. Glad I asked the question here, as I would have invested in an insulation jacket otherwise! Thanks all.