Submitted by UEmd t3_10q02jq in DIY

Specifically, it's a Bradford White RE2H80T6-1NCWT 80 Gallon AeroTherm Heat Pump Water Heater, 240 Volt/4500 Watts. Do you need to have a clearance between where the hot-water-out pipe leaves the tank, or can you put insulation foam over the entire visible stretch of pipe?

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Ok-Apricot-3156 t1_j6n1e0f wrote

Use tube isolation and put tonzon foil around it, never insulate cold water pipes as it increases the risk of legionella

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Bott t1_j6n4vj0 wrote

Do you mean don't insulate the cold water pipes in your home, or don't insulate the cold water pipe going into the water heater?

I found that the cold water pipe (about 1 or 2 feet of it) going into the water heater was warm, and I insulated that. Should I remove that 1 or 2 feet of insulation?

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NagromYargTrebloc t1_j6njxai wrote

I have never understood the wisdom of insulating a few feet of hot water pipe from the tank to where it disappears into the inaccessible reaches of the house upstream. In my case, I have only about 4' of 1/2" copper hot water pipe below a finished ceiling. That only about 1 pint of water.

Never insulate cold water lines. The insulation will trap condensation and hold it against the pipe. Two things can happen: 1. Legionella bacteria can be formed, and 2. U.I.C. can happen causing pinhole leaks.

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magaoitin t1_j6otyi3 wrote

Yea 99% of the new tanks out there do not need any additional insulation on the tank. All of the energy efficiency requirements that have to meet put them in a much different category than even a tank that is 10 years old. It's the pre-2000 tanks that have been well maintained and are still working that can benefit from a tank wrap.

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magaoitin t1_j6ous9g wrote

I agree. I have only ever insulated hot water lines when they enter an unconditioned/vented, or uninsulated crawlspace.

That being said, there is no reason you cannot insulate from the tank to the wall. Just not sure what benefit it has.

Maybe if it was new construction and you are insulating to get a zero offset heat waste for being as "green" as possible you could insulate 100% of your hot water lines, but at that point you are probably insulating all the interior walls because you already drank the Kool-Aid™ of "perfectly" insulated and sealed home construction.

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