Hot Water Line Insulation

[John]

Greetings, I'm planning to insulate my copper hot water piping under the house as the first step to resolving some household hot water issues. My hot water piping is all copper 3/4" and 1/2" soldered piping hung in a crawlspace (house built in 1996 in South Carolina). It is all hung tightly to the bottom of the floor joists using copper-coated wire hangers. I'd like to use the closed cell foam insulation tubes that are split down one side to insulate the lines. However, this would appear to require either notching the insulation at each floor joint- piping intersection or removing the hangers and trying to move the piping away from the floor joists then replacing the hangers with some other design.

Will notching the insulation for the floor joists negate the insulation effectiveness? What kind of hangers are there for insulated pipe? Will they introduce piping noise? What is the best option?

With much respect. John, Who lives with a wife and two teenage daughters and is tired of cold showers!

[Tom]

I'd suggest notching at the hangers. If you want to get fancy, use some expandable foam to seal the notch to the joist.

Insulating the crawlspace would also help and keep the floors warmer. Another alternative is a water circulator that installs at the water heater and circulates the hot water back through the cold water line. They are about $180 at Costco.

[ransley]

I would cut it but use the pipe insulation that has 2 glued sides and a plastic tape you remove, it seals completely. Closed cell foam is extremely expensive and used for freon lines, what you normaly buy for hot water is open cell foam, I think closed cell is 5x the price, you might get a piece of open cell for 1.50$ for 5 ft

[Bob M.]

How far is the shower from the water heater?

If the idea for insulation is simply to keep the pipes warmer, then an inch or two of no insulation every few feet probably won't matter much. If it matters to you, use the spray on foam in those areas.

How about plastic pipe (yes, I know copper is already installed)?

However, perhaps the better solution is to build a heat trap at the heater. Make a loop out of copper pipe, and when no one's using hot water, it is trapped in the tank due to the laws of physics. I wouldn't buy one of those heat traps you can get at supply houses; their little rubber flapper will eventually a) get bent in the out-flowing direction (making it worthless), or b) break off & get stuck somewhere. With a copper pipe loop, none of these problems will show up.

[David Combs]

Your following paragraph: could you please explain it bit?

Like, why is it trapped in the tank do to a copper-pipe loop

*outside* (although maybe pushed up against it)?

And, what's a heat-trap? And as part of the explanation of what it is and how it works, xhat's the rubber flapper for?

THANKS!

David