Measure the cylinder’s height and diameter, then compare both dimensions with the jacket label.
Insulating Covers for Hot-Water Tanks
An older hot-water cylinder without enough insulation can lose heat between uses. MacBlair lists hot-water cylinder jackets marked 36 x 18 inches and 42 x 18 inches, plus separate jackets for 4-gallon and 50-gallon cold-water tanks. These are different products: check whether the task is retaining heat or protecting a cold-water store.
Measure the cylinder height and diameter before choosing a jacket, allowing for the shape of the top and any accessible controls. A cover should fit without blocking labels, valves or maintenance points. If the tank cupboard also needs plumbing repairs, check the pipe fittings separately; a jacket does not replace lagging on exposed hot-water pipes.
If the cylinder itself is being replaced, compare the available heat-source setup and consider whether a new model already has factory-fitted insulation. The wider plumbing and heating section contains related parts for the job. A jacket is a simple improvement, but it will not repair a leaking or poorly controlled cylinder.
Water Cylinder Jacket FAQs
Check the cylinder and jacket instructions. Extra insulation may not be needed or may obstruct access.
Yes, fitting insulation to an inadequately insulated hot-water cylinder can reduce standing heat loss.
No. They are shaped and sized for different vessels and purposes.
No. Keep safety devices, labels and service points accessible as required by the manufacturer.