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Replace water heater?

mike_s

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Nov 22, 2010
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132

So my garage has the standard 40 gallon 208vac/30 amp water heater that feeds a shower that a I never use and a big sink that I might use twice a month.


My question are:
1.) Should I replace it with something like an electric instant heater mounted on wall?

2.) What would my break even point be? (I pay about 8 or 9 cents per kwh)

3) what models would you recommend? (Currently have 30 amp double pole breaker to location, but can upgrade if needed)

4) any other suggestions?

Thanks Mike
 
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mires

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Columbia, MO
Is there anything wrong with the heater that is in there or are you just thinking from a future money saving standpoint?
 

KDXSR5

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The first question I would ask myself is how much money do I want to spend right now? The next question I would ask myself is what is my expected hot water usage? The last quesion I would ask myself is how much do I want to pay per month for energy use?

EDIT: A point of use unit as reccomended above is a good option, and one that my father in law uses at his shop. It would be low upfront cost, low to moderate demand, and low to moderate energy costs. This is a good option if it fits your application.

If I wanted to spend little up front (low), my usage was low to moderate, and I wasn't super concerned about energy costs, I would install a smaller electric unit, possibly one for a mobile home.

If I was ok spending a bit more upfront (low-moderate to moderate), my usage was going to be moderate, and I didn't care about energy costs, I would replace it with another 40 gal electric heater.

If I wanted to spend even more upfront (moderate to moderate high), my usage was moderate to moderate-high, and I wanted lower energy costs, I would put in a 40-50 gal natural gas unit. (I did this about 2 months ago, total cost was $800, but I was replacing a gas unit with another gas unit. Your costs would be higher because you are currently electric.)

If I was ok with moderate high to very high initial costs, moderate to high hot water demand, and low energy costs, I would use an on demand tankless natural gas unit.

Different strokes for different folks. I wanted to do the on demand tankless gas unit, but I didn't have $3-4k laying around to put in a unit like that. What I did have was $1000 laying around, so I went with a higher end 50 gal natural gas unit. Best of luck with your upgrade. Let us know what you decide and why you chose it.
 
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Norcal

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Even a 10 gallon water heater could be used for a shower if your quick, but since it's not being used, there are small electric instant water heaters that would be perfect for a sink, heating 40 gallons of water for occasionally washing hands is a waste of money, could leave the existing water heater in place & shut it off, just having a instant for the sink.
 

captain14

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Near College Park Maryland 20740
Even a 10 gallon water heater could be used for a shower if your quick, but since it's not being used, there are small electric instant water heaters that would be perfect for a sink, heating 40 gallons of water for occasionally washing hands is a waste of money, could leave the existing water heater in place & shut it off, just having a instant for the sink.

Could this be accomplished with a couple of 1/4 v valves to isolate one or the other?
 

kbs2244

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The standard 10 gal type are cheap and do not use much power since they are not heating much water.
Your water usage is too low to justify an instant heater price.
But the cheapest of all would be an insulating kit for your current heater until it dies.
 

lynnbilodeau

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Do you have Natural Gas available?

If so, you might check with your natural gas provider to see if there are rebates available. If so, the "break even" or "payback" period can be drastically shortened.

ONG here in Oklahoma just approved our $850 rebate for converting from a 50 gal electric to a tankless natural gas.

Nice tankless NG units can be pricey, but you have time to shop around for a deal, which is what I did.

This Jacuzzi brand is simply a relabeled Rinnai. It is what I have and we are very happy with it. http://www.ebay.com/itm/BRAND-NEW-J...Natural-Gas-/121761149666?hash=item1c5987b2e2

Venting can be a pain, and another expense, but again, you can shop around. I had to cut a 8" round hole through a 19" thick brick wall. Everything else was easy.
 
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JamesW84

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Springfield, MO
I would either get the smallest tank elec heater or just do without hot water in the garage. If you need hot water, go in the house twice a month...
 

Norcal

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Put the POU water heater under the sink & get the cold water supply for it from the sink CW supply, with the existing HW water shut off, the 40 gallon WH can have the power shut off, if it was desired to use it later, flush the tank, refill & turn it back on.
 

Tucko

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So, a shower you never use, and a sink you use twice a month. Why do you even NEED hot water? :dunno:
 

nadogail

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Coronado, CA
My Garage/Workshop uses a 120 volt Bosch water heater I purchased from Zoro.
I don't have a shower, just a repurposed kitchen sink for hand washing and general cleanup.
I strongly encourage their use.
 
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Richard Cranium

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I used one of the little 1/2 gallon instant water heater like people put on their kitchen sink for a hot cup of coffee or tea. I plumbed it into the regular hot water side of my faucet. But see what the cobbler posted up that looks like the ticket to me. Rich
 

404

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Turn water heater CB off. Turn back on half hour before using sink the 2 times a month. Turn off when done. Cost zero.
 
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mike_s

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Is there anything wrong with the heater that is in there or are you just thinking from a future money saving standpoint?

Nothing wrong with existing 40 gallon water heater.
It's just a
1.) space issue (would rather use that closet for air compressor)
2.) saving money keeping heating it.



Even a 10 gallon water heater could be used for a shower if your quick, but since it's not being used, there are small electric instant water heaters that would be perfect for a sink, heating 40 gallons of water for occasionally washing hands is a waste of money, could leave the existing water heater in place & shut it off, just having a instant for the sink.


That might be one option to keep from heating it all the time.
 
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mike_s

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reading the reviews of these 30amp/220-240v Instant water heaters, it doesn't look like a lot of people think that's enough of a unit to have a warm shower.

I was trying to keep from having to pull new electrical line, but it looks like it would be better if I just bit it and did it.
 

Dennis Leigh Henry

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At the painting contractor I worked for we had a slop sink (utility sink) in the paint shop area.. that had a tiny water heater under it (CNG I believe). It worked well for washing hands, etc. but for extended jobs that required hot or warm water it forced me (us) to use the hot water function sparingly as the recovery time was fairly quick but not instant.. It had insulation on it and had to have cost peanuts vs the one we had at the old shop (hooked to the old boiler system via a heat exchanger that we had there if memory serves..).
 

Brian_WK

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Also if you are in an area that has colder grounds water. Having the water heater sit there and warm up to room temp will allow you to wash your hands with 60-70 degree water (if your garage is heated) rather then ground water temp.
That doesn't solve your wanting to use the space for an air compressor but it is free. And leaves you with the option to have hot water then.

Otherwise i'd say a 120V POU heater under the sink with a low flow high pressure Aerator.

Brian
 

TAMPAGT07

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Palm Harbor, Fl
So, a shower you never use, and a sink you use twice a month. Why do you even NEED hot water? :dunno:

Bingo, this.... Op, please tell me that you do shower in the house....Just not in the garage.... I'd hate to think that you are the "Pigpen" of the GJ...:eyecrazy:
 
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mike_s

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So here is an interesting website.
http://energy.gov/eere/femp/energy-cost-calculator-electric-and-gas-water-heaters-0


So assume that the average family uses 80 gallons of hot water a day.
say 40 gallon in the morning for showers,
30 a day for clothes washer and dishwasher and sinks.
10 a day for kids bath at night.

Consider that most electric 40 gallon heaters have two elements in them, that they are .86 power efficient and .08/kwh electric cost

Per the above website. that would run you about $508/year in energy costs. (about $42/month)


So if we have a 40 gallon water heater in a garage and use it for washing hands a few times a month but no showers or other, then maybe 1 gallon a month, or say 2 gallons...
That would run $13/year. Or about $1/month.

So for $1/month, unless you need the space.... might not be worth turning off (circuit breaker) to save power or replacing.

Those numbers seem accurate ?
 

pmiranda

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I'm thinking there's a base level of power consumption to keep the tank hot even when no water flows. Maybe it's nothing worth worrying over, although I would worry more about the thermostat failing than the cost of electricity in the thing.
 

78scotts

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Minnesota
I have a friend that is a plumber/well driller and asked him about a on demand water heater for my shop. He said with well water they never last, they build up with sediment.
 

Brian_WK

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NE South Dakota
So here is an interesting website.
http://energy.gov/eere/femp/energy-cost-calculator-electric-and-gas-water-heaters-0


So assume that the average family uses 80 gallons of hot water a day.
say 40 gallon in the morning for showers,
30 a day for clothes washer and dishwasher and sinks.
10 a day for kids bath at night.

Consider that most electric 40 gallon heaters have two elements in them, that they are .86 power efficient and .08/kwh electric cost

Per the above website. that would run you about $508/year in energy costs. (about $42/month)


So if we have a 40 gallon water heater in a garage and use it for washing hands a few times a month but no showers or other, then maybe 1 gallon a month, or say 2 gallons...
That would run $13/year. Or about $1/month.

So for $1/month, unless you need the space.... might not be worth turning off (circuit breaker) to save power or replacing.

Those numbers seem accurate ?

I don't think that this takes into account heat loss of the tank. Most electric water heaters you can put your hand on it and you can feel the heat. So if that heat is going into the air in the summer time you are wasting it. In the winter time it doesn't really matter unless you heat the shop with something that is more cost efficient. The water heater keeps the tank warm no matter what water is used.

Also if the bathroom is on the other side of the shop and you have to run the water for 2 minutes to get hot water you have take into account that every time you wash your hands as you have to heat the pipes the whole way as well and lose all the heat that was stored in the pipes as it disperses.

My 40 gallon water heater (plain Jane no special insulating) when the house is unoccupied uses about $0.01 of electricity an hour on average so about $0.24 a day. This is in a conditioned space at about 70F. So take that $0.24 x 30days = $7.20 a month x 12 months = 86.40 a year. That would be a no load no use situation. I collected this data using an efergy house monitor and a Multi-meter with data logging.

So I would say it would be worth it to shut the breaker off for the 2 times a month you wash your hands. But you will still be heating up a 40 gallon water heater every time you turn the breaker back on. So 80 gallons a month.

Brian
 
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mike_s

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I don't think that this takes into account heat loss of the tank. Most electric water heaters you can put your hand on it and you can feel the heat. So if that heat is going into the air in the summer time you are wasting it. In the winter time it doesn't really matter unless you heat the shop with something that is more cost efficient. The water heater keeps the tank warm no matter what water is used.

Also if the bathroom is on the other side of the shop and you have to run the water for 2 minutes to get hot water you have take into account that every time you wash your hands as you have to heat the pipes the whole way as well and lose all the heat that was stored in the pipes as it disperses.

My 40 gallon water heater (plain Jane no special insulating) when the house is unoccupied uses about $0.01 of electricity an hour on average so about $0.24 a day. This is in a conditioned space at about 70F. So take that $0.24 x 30days = $7.20 a month x 12 months = 86.40 a year. That would be a no load no use situation. I collected this data using an efergy house monitor and a Multi-meter with data logging.


that sounds more accurate.
 
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