Our new (to us) house has a system boiler and a vented tank, miles apart. With the heating not on yet, the room that the tank in is considerably warmer, even though the cylinder is fairly modern and has a good jacket on. And I can’t help but think there’s heat pissing out between the boiler in the uninsulated lean-to and the rest of the heating system. So lagging is needed. Which type to use? Cheap foam? Cloth type wrap? Foil backed wrap? I’m fancying the wrap types to help go round the various pipe bends and joins around the cylinder.

Cheap foam.

Polyethylene. Cheap and fairly easy. It does degrade though.

Armaflex pipe lagging and glue to match or tape