Automating my gas water heater.

[steven r]

I realize this question is sort of stretching the scope of this forum but wanted to gleam a bit of knowledge anyone out there that might know something.

I had this idea of rigging some sort of device to turn down my gas water heater when I wasn't home. I figured that there was no point in running it while I wasn't there. The water heater is in my garage and I walk by it every time I go to my car. I've started turning it down when I think about it and turning it back up when I return. I haven't noticed it needing to come back on when I return so I'm beginning to think I'm wasting my time considering this idea. It could be that the thing is so d*** efficient that it isn't losing any noticeable heat when turned down for the day or could be that it's just the middle of the summer in the South.

Does anyone know or know where to find out the relative savings of setting a gas water heater to an average setting versus a full setting? Keeping in mind the higher the temperature is set the less hot water I'll use. i.e. The ratio of  ^Hot/_Cold water used is less for a given shower temperature the higher the heater is set.

Again I realize this is a bit of an unusual question for this forum but at least 1 inquiring mind wants to know.

[Mavrik]

Get a tankless water heater, best thing I ever purchased. I only pay for hot water when I'm using it, instead of heating 30+ gallons 24/7 356 days a year. Even if I had a leaking hot water tap, the flow switch will not activate for this small flow. On top of all this, I never run out of hot water.

[Dan Lawrence]

As far as X10 is concerned, nothing is available to control gas appliances, AFAIK. X10 is useful for controlling lamps and electric appliances. The only way X10 could is if the electric control valve (from the internal thermostat) is 110 volts AC (not usually) then an appliance module could be added to the circuit to turn the electric part on and off. I could not see much use for it, though.

[TakeTheActive]

Get a tankless water heater, best thing I ever purchased. I only pay for hot water when I'm using it, instead of heating 30+ gallons 24/7 356 days a year. Even if I had a leaking hot water tap, the flow switch will not activate for this small flow. On top of all this, I never run out of hot water.

• Did you do much research before purchasing?
  .
• What Brand / Model did you buy?
  .
• How does the price compare to a "Standard" 30 or 40 Gallon HW Heater?

Thanks!

[Mavrik]

No, I didn't do any research, it's a no brainier. While your not using hot water, you pay nothing. How many times a day do you hear the water heater come on when your not using hot water. Your paying for this. What goes wrong with tank heaters, the tank leaks after 8-9 years. How many times have you ran out/low of hot water.

I bought an electric Titan SCR2 for $200 shipped. $50 to install myself (copper pipe, larger breaker and larger wire). Price some tank heaters, they are more than this. A gas tankless unit may run you considerably more, but it may be worth it to convert to electric. I believe electric may be cheaper than gas.

This tankless water heater measures 11 inches high, 7 inches wide, 3 inches deep. Think of the added space.

It pays for itself with lower utility bills and you don't have to buy another tank in 8-9 years.

[sk00ter]

When I go on vacation or away for a couple days I shut off the gas valve to my hot water tank.

If you just want to keep yours down while you are away it might not be a good idea because when you come back its gonna take awhile to reheat the entire tank again using more gas than it might as opposed to not turning it down.

[steven r]

No, I didn't do any research, it's a no brainier....

Well not exactly...

I know that a tankless water heater can save money in many cases but there are other things to consider. From my research several years ago...

• In my case. I'm in a new home. (i.e. New gas water tank) I doubt it would be cost effective to remove a tank that is in excellent condition. Maybe in 10 years.
• Costwise how does using an electric tankless water heater compare with a gas water tank heater? How do gas tankless water heaters compare with the electric ones? Take into consideration unit cost and energy cost over say a 10 or 15 year time period.
• The gallons per minute for a tankless heater typically isn't as great as a water tank. i.e. You may have reduced pressure if you try to shower while the dishwasher and the washing machine are on. You need to make sure that the tankless heater you buy will meet your temperature and output needs.
• What is the life expectancy for a tankless heater. Do they last as long as the tank ones. Longer?

Those are a few of the questions I'd have to have answered before purchasing a tankless heater.

I found this article to be interesting.

[steven r]

...it might not be a good idea because when you come back its gonna take awhile to reheat the entire tank again using more gas than it might as opposed to not turning it down.

This is the kind of question I'd like to get a clear answer about. In my case, it appears that the only time it heats is to warm replacement water. I've turned it down for several hours and not have the heater need to come on when I've turned it back up. Of course my results my be different this winter.

[KDR]

Another thing to consider especially if the tank has some age on it is leakage. Both electric and gas, if shut off for a long period of time and allowed to cool down that may cause the tank to leak. I have seen this in both types. I have seen people get lucky and turn the tank back up and as soon as it got hot the leak stopped. Seen it go the other way and not stop. If you are trying to control it to cycle from a low range to a higher range I don't think you will see any benefit or very little in fuel savings with maybe the exception of propane which as I recall has a higher BTU output for the same volume of fuel burnt.

[Mavrik]

I'm not a salesman, I'm happy with my tankless and thought I would share. My tank water heater did spring a leak, so it was imperative to have a replacement. Made it a no brainier for me. The manufacture says it saves 60%, which is easy for me to believe since I herd my tank water heater coming on several times a day/night in summer. It was cold to the touch so it was well insulated.

Put a hour meter and counter on the control circuit to see what it is actually doing with no water demand (and with demand) and build a log. You can figure the gas usage by timing one minute on the gas meter. The label is probably inaccurate, since you may not know if your water heater has been tuned for maximum output. Imagine if your water heater was built around a holiday, you know what that is like

More reading to ponder...   http://www.titanheater.com/tankless_water_heater.php

[steven r]

...Put a hour meter and counter on the control circuit to see what it is actually doing with no water demand (and with demand) and build a log. You can figure the gas usage by timing one minute on the gas meter....

Probably the only way to really know for sure.

This link gives an overview of water heaters from the company that makes a nice hot water pump. Their hot water pump is useful in both tank or tankless situations. I'm very pleased mine.

[sk00ter]

Another thing to consider especially if the tank has some age on it is leakage. Both electric and gas, if shut off for a long period of time and allowed to cool down that may cause the tank to leak. I have seen this in both types. I have seen people get lucky and turn the tank back up and as soon as it got hot the leak stopped. Seen it go the other way and not stop. If you are trying to control it to cycle from a low range to a higher range I don't think you will see any benefit or very little in fuel savings with maybe the exception of propane which as I recall has a higher BTU output for the same volume of fuel burnt.

What would cause it to leak?  I've been doing this for many years(shutting gas off while on vacation) and never developed any leaks.   Maybe I got lucky!

Sk00ter

[sk00ter]

...it might not be a good idea because when you come back its gonna take awhile to reheat the entire tank again using more gas than it might as opposed to not turning it down.

This is the kind of question I'd like to get a clear answer about. In my case, it appears that the only time it heats is to warm replacement water. I've turned it down for several hours and not have the heater need to come on when I've turned it back up. Of course my results my be different this winter.

I think if  your water temp gets below a certain temperature the gas will come on to heat the water in the tank even if no water has been used.

sk00ter

[nlosinski]

this is more for non gas but, heres a link for a  ELK 30-Amp Appliance Relay Module

this should help you, and everyone else that wants there hot water heater to work with x-10 systems...

http://www.hnausa.com/detail.aspx?ID=31

good luck,

Nate

[gil shultz]

Automating my gas water heater
Why Bother.  With the insulation of the newer heaters the loss are minimal.  You can easily add an external insulation blanket designed for water heaters.  If you keep changing the setting, you probably will suffer a premature valve failure costing you far more then you saved.  It is not a good idea to shut the heater off completely as it cools water will condense on the outside tank and heating area causing it to corrode.  At least leave the pilot light on as the manufacturer recommends.  The best setting is the lowest that you can comfortably live with.  Typically, the cooler the tank the longer the life.

Gil Shultz