On demand water heaters

[bgosh]

Has anyone switched from a tank water heater to a on demand water heater? Does it work as expected? Any pros and cons about these would certainty be appreciated. For now just thinking and looking for comments . Thanks Stan

[jamesglenn]

I switched from an oil fired water tank heater to an LPG tankless heater. Works better than expected. The key is to have a recirculation pump and a return line from the farthest point possible, this provides ready hot water at the tap when you need it. Otherwise I have to wait 45 or more seconds before hot water comes out.

Mine has a control panel with a timer for the built-in recirc. pump and the unit only heats for a few hours in the morning and night since the family is not in the house all day.

Venting is important for the NG and LPG models. I am not too familiar with the electric models.

[fixtureman]

jamesglenn said:

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I switched from an oil fired water tank heater to an LPG tankless heater. Works better than expected. The key is to have a recirculation pump and a return line from the farthest point possible, this provides ready hot water at the tap when you need it. Otherwise I have to wait 45 or more seconds before hot water comes out.

Mine has a control panel with a timer for the built-in recirc. pump and the unit only heats for a few hours in the morning and night since the family is not in the house all day.

Venting is important for the NG and LPG models. I am not too familiar with the electric models.

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Doesn't that defeat the idea of the on demand heater as it would be heating all the time the timer is on

[K. L. McReynolds]

Still less expensive, since the volume of water being heated is much smaller than an entire conventional water tank. And even less expensive than having the same set up on a conventional heater.

[blackhat]

Yes I switched. I have switched a bunch of customers and didn't switch some as well. Many pros and cons. What do you hope to gain from a switch?

[dlorenz]

I checked into electric on-demand water heaters in '08 when we built our last house. As I recall, they required an 80 amp circuit, were quite expensive, and only had a 1 year warranty - I was not impressed, so I went with a regular water heater.

I suspect a gas model would be a better choice for on-demand.

[bgosh]

Nothing real specific just thinking.One thing ,what would be the life expectancy,another would be auto venting (fan assisted) not sure if I got that right.From what little I have found out is the actual price seems to be about the same. Do you feel that lag to get warm water is bothersome? Stan

[jteneyck]

Run the numbers and I'll bet you'll find an on-demand heater will never pay for itself in energy savings over a conventional tank water heater. There may be special circumstances where you would choose one, but I don't think those are typical.

I don't understand why the lag time would be any different between an on-demand and a conventional tank. Both give you hot water immediately. It's the distance the water has to travel to the tap that matters.

John

[blackhat]

Your numbers might be different if you compare cost to a 150 gal water heater that could fill my big jet tub in one shot. Different needs. The time lag issue was more prevalent with early models. They took 10 to 12 seconds to start the burner and come to temp once flow was established. Add that to the 20 seconds it used to take and you have a customer that bitchs it takes twice as long and wastes 3 times as much water. New units typically store a little bit of warm water internally and are running in 2 to 3 seconds.

[MKepke]

There have been a bunch of threads on this topic in the last several months..recommend you start with those via the Search function.

-Mark