I have some copper pipes used for forced hot water heat that run in an unheated area behind an upstairs wall. I want to insulate the pipes because the heat they throw off cause ice dams on my roof, and also, I want to save money by keeping the heat in and prevent them from possibly freezing. I‘ve seen three types of insulation for pipes:- a styrofoam kind that is very cheap in price.- a rubber kind that is expensive but looks to be higher quality.- a fiberglass kind that is just a bit less expensive than the rubber kind.I‘m not sure what is the best type to keep the heat in the pipes and protect them from freezing as well.
The Greenish marks are flux which was used to solder the copper joints. It is harmless and usually appears about a couple of months after soldering. it can be cleaned off easily.
The fiberglass is your best bet. Styrofoam is next to worthless. The rubber kind is primarily used for cooling systems, not heating. If the pipes are in a residential home, 1 thick fiberglass will do the trick. Less than 1 will not provide the protection or savings to be worthwhile.
Insultube, made to go over the pipes is the best, sold in 5' lengths. Most comes pre-slit just slide it onto the pipe and seal off all the joints with duct tape. R value I believe is 3 so if freezing is a concern you may want to have anti-freeze added to your boiler system.
