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Ok, so I took a few weekends and totally insulated all hot water pipes I could get access to from the water heater. Now, I still wait approx 90 seconds for hot water to reach the farthest faucet from the water heater.

So my question, does anyone find insulating pipes useful? I feel like I wasted time and money. The insulation I used was both fiber and foam.

I'm now looking at water circulation pumps but the wife is skeptical of my projects to have hot water fast at that farthest faucet.

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up vote 6 down vote accepted

Insulating water pipes reduces the speed that they lose their temperature with the ambient air. This can reduce the risk of the pipes freezing in an outdoor location. For the indoors, it keeps the pipes warmer for longer, which may help for frequent tasks that don't require hot water, like hand washing.

But once the pipes have cooled off it doesn't increase the speed that water takes to travel from the hot water heater to your fixtures. If you need to reduce that time, you may want to consider adding a hot water recirculating pump that ensures the water is always hot at your fixture.

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Thanks, I think I agree on needing a hot water recirculating. Is there such a thing as a good one? Meaning, money aside, which would be ideal to have? So far I've searched and Grundfos Alpha 2 seems to be it since it can regulate itself to use little electricity based on usage. – Jose Leon Dec 26 '12 at 13:56
@user706837 I don't have any brand specific advice, but there are two different styles – BMitch Dec 27 '12 at 12:13
If the long wait is primarily at only one or two faucets, it would be more energy efficient to install instantaneous heaters instead of circulating pumps. There are many factors to consider to determine of this is a feasible solution, but certainly worth considering. – bcworkz Dec 27 '12 at 18:35

I did the same last year and noticed the same: time to get hot water at the extremities seems the same because the pipes are cold after a long period of time no matter what.

What I haven't got a feeling for is whether it's quicker to get hot water after the pipe has been heated recently. We just don't have water usage that would benefit from that, yet. I think/hope that in that use case the performance will be a bit better.

The alternative that I view is having some kind of recirculation system, but I don't know how to calculate the benefits of that. It seems like a lot of energy could be wasted if things don't exactly fit the schedule of the recirculation system.

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Cost of city water vs electrical power consumption would be a good analysis. With the pipes properly insulated, will the electric bill go up more than the water bill will be reduced by lessened water waste. – Fiasco Labs Dec 27 '12 at 2:22

Insulating the pipes will of course make the water in the pipes cool down slower, but once it's too cool for your shower (or whatever), you'll still have to wait the same time for hot water to arrive from the tank. To eliminate the wait, you can add a second pipe back to the tank (connecting to the cold water intake pipe, or thereabouts) and a circulator pump. The pump could be small. There may be smart systems that shut it off late at night or while you're on vacation. You would definitely want all those pipes insulated.

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There are also ones that don't need a loop and instead push the water back over the cold supply line – Steven Dec 26 '12 at 17:14

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