Insulating outdoor pipes? (Phoenix: house, water heater, plumber)

[Voebe]

I have some pipes that were re-routed over the roof. At the time, they didn't bother to tell me that they might freeze and burst in the winter. For Phoenix, with the comparatively warm weather, this didn't even cross my mind. So after a couple of years of this, someone told me I should insulate them with foam tubes, which I did. But they didn't bother to tell me that the foam breaks down fairly quickly, and this has to be re-done every couple of years.

Now a handyman just told me that I should instead use a kind of insulating tape that gets wound around the pipes. He said it would much longer. (Actually, he said "forever," which I doubt.) But a plumber told me that's not true at all.

Now, with Phoenix weather hitting freezing more than I ever realized - if you have outdoor pipes, do you have any personal opinions as to whether the tape is better? I assume it's messier and more time-consuming, so I wasn't going to switch unless it's an improvement.

[Ponderosa]

I think everyone has the service pipes near the front of the house above ground and uninsulated. We do hear stories of some freezing every winter. But, since they are low to the ground that is pretty rare and easily prevented by just covering them on the nights that it is predicted to get very cold. But on the roof is a whole different ball of wax. It can get much colder up there than down near the ground where the heat radiated from the soil keeps things in line. I remember the day when there were solar water heaters everywhere around here. Many of them conked out in short order when they froze up. I would do something to insulate any pipes not near the ground. That foam stuff from Home Depot will do the job, but it probably will not last one summer in the sun as you have learned. I don't know what your handyman is offering, but get a warranty from him!