Lagging tanks and pipes will save energy and money.
This is an easy job to do and the materials are readily available at DIY stores and are fairly inexpensive.
If you have a hot water tank it should have at least a 75mm(3inch) jacket around it. They usually come in different sizes so measure the height and diameter of your tank. Common sizes are 36"x 18" and 48" x 18". The jacket comes in sections which you tie together as you wrap it around the tank. Buy one online at: