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paulb · 18-09-2007, 15:59

Hi,

Does anyone know how thermally efficient pre-insulated hot water cylinders are? I have my HWC in the attic, i.e. above the insulated body of the house, the pipes leading down into the house are lagged but I was wondering if putting an extra lagging jacket on the HWC would improve the thermal efficiency, it get's cold up there!

Any advice appreciated.

Paulb

10-10-20 · 18-09-2007, 16:13

I don't have any data on that, but the insulation is known to be pretty good.
Saying that, if your attic is drafty or if the cylinder is outside the insulation envelope (i.e. sitting above the insulation on the ceiling) you are going to have somewhat higher losses than you would if the tank was in a hotpress.

Consideration could be given to creating a draft-proof enclosure around the tank and piping and lagging it, or by additionally lagging the tank and associated piping with a rockwool with a single foil/plastic layer on the exterior. This would reduce the losses from any drafts somewhat.

MartinCorcoran · 19-09-2007, 22:40

Yep, the pre-insulated tanks are excellent. Fitted one recently and the hot press is no longer the hot any more (if you know what I mean)

18-09-2007, 15:59	#1
paulb Registered User Join Date: May 2005 Posts: 31 Adverts \| Friends	Hot Water Cylinder query Hi, Does anyone know how thermally efficient pre-insulated hot water cylinders are? I have my HWC in the attic, i.e. above the insulated body of the house, the pipes leading down into the house are lagged but I was wondering if putting an extra lagging jacket on the HWC would improve the thermal efficiency, it get's cold up there! Any advice appreciated. Paulb

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18-09-2007, 16:13	#2
10-10-20 Registered User Join Date: Mar 2007 Location: South Dublin Posts: 1,718 Adverts \| Friends	I don't have any data on that, but the insulation is known to be pretty good. Saying that, if your attic is drafty or if the cylinder is outside the insulation envelope (i.e. sitting above the insulation on the ceiling) you are going to have somewhat higher losses than you would if the tank was in a hotpress. Consideration could be given to creating a draft-proof enclosure around the tank and piping and lagging it, or by additionally lagging the tank and associated piping with a rockwool with a single foil/plastic layer on the exterior. This would reduce the losses from any drafts somewhat.

19-09-2007, 22:40	#3
MartinCorcoran Registered User Join Date: Dec 2002 Location: Bray Posts: 649 Adverts \| Friends	Yep, the pre-insulated tanks are excellent. Fitted one recently and the hot press is no longer the hot any more (if you know what I mean)