As commonly available in the stores, these tubes seem to be made of 2
different types of foam, one that is slightly more "rubbery" than the
other. This link says that one is used for copper, the other for
galvanized steel, but it doesn't say which type is for which kind of
Also, what size should the tube be -- just enough to fit over the pipe,
or slightly larger so that there's some sort of an "air gap" between the
tube and the pipe?
The closed cell provides more insulation value. A lot harder to find as it
is a lot more expensive. Get the size for your pipe, snug fit. Then use
plenty of duct tape to hold it on. I use only the metal tape as the other
stuff releases in a couple of years from the heat.
A good razor knife and your good to go
Everything has a law of diminshing return, but true energy efficiency
can not be acheived with out the extra cost. Payback will be evident and
real as I took out a Electric Rheem with a blanket an went fron 30 $ to
6 $. Yes electric is double the cost but my sawings exceded that.
Insulate all pipes of hot water , use closed cell foam the type that
has glue strips installed so taping is not necessary. Doubling
insulation is not a bad idea since 1/3 of gas costs can be heating
Update: I bought both to try, but ended up preferring the "rubbery" type
of insulation (it's similar to neoprene; one brand is Rubatex) rather
than standard foam. Pricing for self-sealing type: standard foam 99
cents / 6ft, rubber-type 3.49/6ft.
The rubber-type was much easier to install. It stretched around elbows
so it didn't need cutting, and could easily go around "T"s. It was much
easier to fit around multiple short-segmented areas like up to the
Thx to responders for advice.
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