1 Mar 2016
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United Kingdom
Hi All ...

First ever post.

I have just bought a one bed one bathroom ground floor flat with not a lot going for it in the way of storage. Currently in the hall way there is a cupboard that houses an immersion tank, shower pump and also water tank. The place has no gas so a combi is out of the question. It also has storage heaters.

This all takes up masses of space so i'm looking to take out what I can and upgrade the whole set up to something less large and hopefully more economical.

After speaking with various plumbers/heating engineers I was told a megaflow (or another brand of unvented water cylinder) was the way to go and that this could likely fit into a double height kitchen unit which would then totally free up cupboard space in the hallway.

Does anybody have any alternative recommendations to installing an unvented cylinder?

And have people seen them small enough to fit inside a 600mm double height kitchen unit?

Any advice would be most welcome.


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I was thinking along the lines of a small instantaneous heater that can fit in a cupboard if you don't need to fill a bath, but then it appears the shower is fed from the stored hot water. Whatever you do, needs to have sufficient to supply a shower for a reasonable duration. If you go unvented you will need an installer with a G3 ticket to qualify them to fit unvented.

If the current setup if well insulated and run on Economy 7 I suspect you are unlikely to save much, and indeed the outlay of changing it all may take some years to recover. Depends how much you value extra storage really.
Last edited:
Cheers for the reply.

Yeah, whatever is fitted needs to be large enough to fill a bath. Unvented seems to be the way to go. Wanted to know if anybody had seen one that would fit in a 600mm double unit. From what I've read I think 120/125 litre would do the job.

I have a G3 installer that could do the work, I just wanted to know I'd looked into all options before making a decision!!
I suspect that you'll be pushing it to install inside a 600 unit - available width would be 560 mm inside the carcass - Megaflo diameters are 579 mm
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Yeh I've fitted one in a unit before. Just make sure you support the base as to take the weight.
You can get horizontal unvented cylinders from eg Telford, including in their slimline range (470 mm dia). I don't know if you have the ceiling height to put one overhead on a platform eg with fitted wardrobes underneath, or have it underneath a raised bed, or indeed could spare the under-worktop space in the kitchen.

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