Tricky loft header tank insulation job

[benawhile]

The open vented header tanks in my loft are arranged one on top of the other. The main feed to the HWC is mounted on the joists, and the central heating header is mounted via a combination of a horizontal roof strut and a batten secured to the brick chimney wall, so that there is about 2 feet clear space between the top of the main and the bottom of the ch header.

I don’t like this arrangement and would prefer the ch header mounted on the floor next to the main tank but I am stuck with it for now.

There is no loft floor insulation directly underneath the main tank, as common practice, but this is no benefit to the ch header.

Is there a recommended way of enclosing this arrangement so that the rising heat utilised to keep the main tank warm can also be used to warm the ch header?

 

[Doghouse Riley]

Why not make a box out of Kingspan or whatever, to cover the lot? You could tape the four sides and top together with duct tape. If at some time in the future you decided to move the tanks you could still re-use it.

 

[benawhile]

Good idea but stared making a frame now, which I'll cover with bubble wrap or similar, (or maybe even Kingspan!)
But I would need occasional access, also to consider

 

[Doghouse Riley]

If you just used Kingspan the accesswould be easier and it has better insulating prperties than bubblewrap.