Insulating your pipes can save you money. Every year many people have frozen pipes in the winter and if the pipes are not thawed in time they may burst. Once the pipe thaws and the water starts flowing again tremendous damage can result. Even if you don’t have pipes that freeze your hot water flowing through the pipes can lose much of its heat forcing you to use more hot water. Insulating can keep your hot water from losing as much of its heat and save you money as well. In fact your hot water could easily be 3-4 degrees hotter with insulated pipes.
There are many types of insulation for pipes but as far as bang for the buck the six-foot long polyethylene foam insulation is a great choice and is easy to install. It is available under a variety of names such as Armacell Turbolit, and Thermwell Frost-King just to name a couple. The insulation comes in a tube shape and is made for ½”, ¾”, and 1” pipe. The usual length is 6’ and it has a slit running lengthwise the full length of the tube. On the cheaper tube the slit will not be all the way through so it can be slid over the end of a pipe being installed, but it can be opened up to slip over an existing pipe just by running your finger down the slit. After slipping it onto the pipe you just tape it with duct tape to hold it closed and secure lengths together. If you want to pay about twice as much the insulation is also available fully slit with an adhesive on the slit with a plastic sheet that peels off to expose the adhesive, but you will still need duct tape to join the sections. Prices will vary but partially slit foam pipe insulation is probably $0.80 – $1.00 per 3’ length and the fully slit adhesive foam pipe insulation is $1.60 – $1.80 per 3’ length. Personally I use the cheaper stuff I actually consider it easier to use.
In a house that does not have freezing issues I would at a minimum insulate all exposed domestic hot water pipes. In a house that has freezing issues I would insulate the cold water pipes in areas where pipes are exposed to cold temperatures and drafts. Bear in mind that insulation will only slow the rate at which the pipes can freeze and in some cases heat tape should be used. Another place where insulating cold water pipes is in damp basements and crawl spaces where cold water pipes sweat in the summer. Insulating cold water pipes will help prevent pipes from sweating.
The old tale of leaving the water running to keep pipes from freezing is something you should avoid because in many cases a small amount of water left running may cause the drain pipe to freeze. Drain pipes are considerably more difficult to thaw the a supply line due to the size and quite often they are constructed from plastic materials. If your pipes do freeze it is very important to thaw them as soon as possible. In many cases if caught fast enough the pipes may not burst. Under no circumstances when a pipe freezes should a torch be used for thawing. Using torches for thawing pipes is tha cause of many fires each year. Plumbers use a special electric pipe thawing machine that sends electricity through the pipes to warm them that is actually quite safe.