Electric water heater: OK to turn it off?

[LikeLakes]

Originally Posted by SailinAway

It's August 1, the day the new electric rates begin. This month I'm going to experiment with ways to reduce water and electricity usage.

Electric water heater: I need very little hot water. In the summer cold showers would be OK. For washing dishes I can heat water on the stove. Laundry doesn't really require hot water. So I'm paying a lot to keep the water hot in the tank, but I get little return on that investment.

I believe my water heater is set at 120 degrees. I can't set it lower due to the risk of Legionnaire's disease (in fact on study found that the bacteria can grow at 136 degrees). Plan B: Turn off the hot water heater altogether so that cold water is drawn directly from the town water supply. Questions:

(1) How exactly would I do that?

(2) Will the standing water in the water heater cause any damage to the heater or other problems?

(3) When (if) I turn the water heater on in the winter, how would I ensure the safety of the water in the tank?

1) Electric breaker in the fuse box. Possibly a service switch right next to it.
2) No. Full of water, hot or cold, no difference.
3) I'm not sure on that one. I'm of the opinion that you use cold water for potable water, meaning drinking and cooking and brushing teeth. Use hot for showers and dishwashing etc. Keep in mind your cold water may not be great to start with, never know until you test it.

Having said all this, I don't recommend what you are thinking of trying. Warming a few pots of water on the stove will use more energy than full days of the hot water heater. A good quality, well insulated hot water heater doesn't use much energy to keep water up to temp, the energy use is when you use hot water and it has to bring cold up to temp. So if it were me, I'd minimize hot water use with cooler showers etc. but leave the hot water heater on.

[SailinAway]

Originally Posted by LikeLakes

(1) Electric breaker in the fuse box. Possibly a service switch right next to it. . . . Warming a few pots of water on the stove will use more energy than full days of the hot water heater. A good quality, well insulated hot water heater doesn't use much energy to keep water up to temp, the energy use is when you use hot water and it has to bring cold up to temp. So if it were me, I'd minimize hot water use with cooler showers etc. but leave the hot water heater on.

I think you forgot to mention the valves on the water heater?

I'm one person, so washing the dishes takes at most a small kettle of hot water mixed with cold. Literally two minutes on the stove for the whole day's dishes. That's really the only hot water I need in the summer.

[LikeLakes]

Originally Posted by SailinAway

I think you forgot to mention the valves on the water heater?

I'm one person, so washing the dishes takes at most a small kettle of hot water mixed with cold. Literally two minutes on the stove for the whole day's dishes. That's really the only hot water I need in the summer.

No need to shut the valves. IMO you are better off from a health standpoint with full pipes, not pipes partially full and partially with air. By leaving valves open, when you open a hot water faucet cold water will flow through the heater, keeping air out.

I hear what you are saying about not using much water. I'd still leave it on.

[John Mercier]

Many people place them on timers, so that they only heat up about an hour before they need the water and then shut off for the day.

Shutting it off is as simple as flipping the breaker.

[pondguy]

Originally Posted by John Mercier

Many people place them on timers, so that they only heat up about an hour before they need the water and then shut off for the day.

Shutting it off is as simple as flipping the breaker.

My water heater is on a timer and runs 1 hour a day my bill went way down and there is more than enough water for my needs. I have been doing this for many years and always have at least warm water for dishes at the end of the day.

[SailinAway]

Originally Posted by pondguy

My water heater is on a timer and runs 1 hour a day my bill went way down and there is more than enough water for my needs. I have been doing this for many years and always have at least warm water for dishes at the end of the day.

How does that 1 hour work? Is it one continuous hour at a particular time of day? What do you estimate is your monthly electricity cost for hot water?

[pondguy]

It runs as long as it takes within 5 to 6 am to reach 120 degrees. My whole house electric runs around 60.00 in the summer and 80.00 in the winter. Also included is an electric stove and a clothes dryer I use twice a week or so and all lights are LED.

[pondguy]

I'm with the NH Electric Coop and I expect with the new rates my bill will go to 80.00 in the summer and 100.00 in the winter.

[SailinAway]

Originally Posted by pondguy

It runs as long as it takes within 5 to 6 am to reach 120 degrees. My whole house electric runs around 60.00 in the summer and 80.00 in the winter. Also included is an electric stove and a clothes dryer I use twice a week or so and all lights are LED.

That's impressive! No air conditioning or dehumidifier?

[pondguy]

I run an energy star window AC maybe a half dozen times a summer, my house is in the shade so it gets in the 90s only a few times a summer. I like the heat I'm old......lol

[SailinAway]

Originally Posted by LikeLakes

No need to shut the valves. IMO you are better off from a health standpoint with full pipes, not pipes partially full and partially with air. By leaving valves open, when you open a hot water faucet cold water will flow through the heater, keeping air out.

I hear what you are saying about not using much water. I'd still leave it on.

If I don't shut the valves, doesn't that mean the water is coming from the water heater, with the risk of bacteria??

If the valves are closed, why would there be air in the pipes? The pipes would be under pressure from the town water main, no?

[LikeLakes]

Originally Posted by SailinAway

If I don't shut the valves, doesn't that mean the water is coming from the water heater, with the risk of bacteria??

If the valves are closed, why would there be air in the pipes? The pipes would be under pressure from the town water main, no?

To answer your question, with valves open you only get water from the tank if you open a hot water faucet, or push a mixing valve (kitchen sink for example) toward hot. You're right, close both valves and you've "trapped" the water in the tank. I'd still rather leave them open and pressurized, just from my experience with house piping and winterizing, etc.

[SailinAway]

Originally Posted by LikeLakes

To answer your question, with valves open you only get water from the tank if you open a hot water faucet, or push a mixing valve (kitchen sink for example) toward hot. You're right, close both valves and you've "trapped" the water in the tank. I'd still rather leave them open and pressurized, just from my experience with house piping and winterizing, etc.

In my house there are unavoidable mixing valves for the washing machine and shower.

You can't (shouldn't) draw water from the tank unless it's heated to minimum 120 degrees to avoid Legionnaire's bacteria. Thus water should not be drawn from a cold tank. Thus the tank would need to be completely closed off from the household pipes, no?

The presence of Legionnaire's bacteria in rain barrels would also limit the use of that water. Apparently even flushing the toilet with those bacteria present is unsafe. This is all new to me. Sounds important.

[John Mercier]

You would a need a 140F temperature.

https://www.cdc.gov/legionella/wmp/c...r-systems.html

[Bear Islander]

I think a water heater blanket would be a better idea. They are cheap and will reduce heat loss to a negligible amount.

If you also insulate your pipes then the standby loss will be low, and you are only paying to heat the water you use.

As fuel prices go up the sensible answer is more insulation, including walls, windows and attic.

[TheTimeTraveler]

Why not just convert to an "on demand tankless hot water system" which will run only when the hot water is actually called for?

[John Mercier]

An electric version may need a panel and service upgrade.