Instant Hot Water

[Robert Neville]

I've stayed at hotels like that, including the Disneyland Hotel. Extremely annoying.

[Bob F]

[Bob F]

Which introduces a big waste of energy all the time. The push button pump system wastes none. It only warms the pipes when you are going to use the hot water anyway.

[Bob F]

That brings up another issue for the recirc pumps. They are unlikely to work with on-demand water heaters.

[Bob F]

All you need is the button and a time delay relay to replace the timer you already have. Your pump should work fine with the new switch.

[Robert Neville]

Yes, it's the time delay relay I was interested in locating...

[Not]

I think pumping the tepid water into the cold water supply line means you won't have cold water, assuming the pump is in working order.

I like keeping the cold and hot water supply lines separate. When I was remodeling the bathroom, and had easy access to the lines, I added a return line from the far end of the hot water supply line back to the water heater, forming a supply loop. I put a check valve in the return line so when flow is high, the return line is disabled. I insulated the original supply line, and left the return line uninsulated. Through the magic of gravity (more reliable than a pump, and cheaper) there is a constant flow of hot water through the loop, so when we crack the faucet, we get instant hot water. There is no cost for electricity, and no pump to break. I do use a little more gas for the heater, as there is a heat loss from the return line, but that is welcome heat into the house during the cold months.

[clare]

Have you ever checked to see how much power is required to keep a well insulated 5 gallon water heater hot?????? Likely about as much as to run a circulating pump. And it's a lot easier to retrofit to an existing house. You can also put a SWITCH on it, or a TIMER so you only have hot water in reserve when you are likely to want it.

[clare]

Tankless on demand water heaters are a cruel hoax.

[Art Todesco]

I think putting hot water into the cold pipe is not good. Just think, you get up at 3AM and want a drink of water. You get warm water or you then must run the cold to purge out the warm. I would prefer a real loop.

In my new house, everything seems to be connected with 3/4" PEX. The faucets are all lower flow than I'm used to. But, they have made up for the flow with better aerators. Anyway, my kitchen sink it right above the water heater (in the basement). Low flow, coupled with larger pipes and a kitchen faucet that has a pull out hose end, makes for a long wait for hot water. Also, the bathrooms take forever. Unfortunately, they are at opposite ends from the water heater. I was thinking of gravity loops, but I know they don't always work well. I might need 2 pumps to accomplish this ... or one, with some flow adjustments.

[Stormin Mormon]

I keep looking at the subject line and remembering the spoof ad for Instant Hot Water: Just add water and heat.

[Bob F]

I seriously doubt that. A pump using less than an amp, running for 20 seconds a couple time a day will use very little power, compared to ANY tank water heater.

[clare]

But most of the systems are NOT push-button on-demand circulators. And the non-push-button-on-demand systems not only draw constant power running the circulating pump, they also lose heat from the entire circulation loop constantly, meaning the water heater needs to run more.

They are definitely a convenience, but they most certainly are NOT an energy saver.

The push button type? Yes. But the complexity of the required plumbing for a retrofit is significant. The aditional small volume heater is a simple install, and NOT a huge energy waste. - and CAN be set up to run on a timer so you have hot water at , say, bath time.