Hot Water Heaters

[Todd Wilson]

I wanted to ask the panel of experts here what they think would be the most econimcal way to run a standard house hold water heater.  Its usually the rule that the hotter the water the more it costs you to heat......but heres the question.   Are you better off to run the heater on a lesser setting or on a hotter setting.   My thinking is and we will use just a standard set of #'s here  it takes 100 gallons of water to take a shower.   On a warm setting maybe 40 gallons of that water may be from the water heater and the rest from your cold pipe.   Would this be better then say running the heater hotter  and using 20 gallons of HOT water mixed with 80 gallons of cold.  Would there be a savings there as you would only be recovering 20 gallons of hot water instead of 40 gallons of warm water.  Is the savings there or are you better off running at a lower setting and ultimately heating more water?!


Todd

[Silver R/T]

We run ours on lower setting, our gas bill decreased a few bucks so it must work

[dodgecharger-fan]

There is a push around here to get the temp on the water heaters up to make sure nothing grows in the tanks.
"Legionellae Bacteria can grow in water in temperature less than 120 °F"

Then to make it safe, they put an automatic mixing valve right at the output of the tank to mix in some cold to get the water back down to a safe temperature.

It will be code here soon, if not already so.

Here's some info on the valve and the reason for it..
http://www.houseneeds.com/shop/HeatingProducts/HydronicHeating/cashacme/110dmixingvalvebuypage.asp

More info from the manufacturer: http://www.cashacme.com/prod_thermostatics.php

[Silver R/T]

all it is just a thermostat. All it does is keep water at certain temperature. Would it cost more energy to keep 60 gallons of water at 120F or 90F, makes any sense?

[4cruzin]

I guess it depends how often you use the heater.  It will cost more to keep the tank at 130* all the time than it will to keep it at 115*.  If saving money is your name of the game, then a lower setting is probably the way to go.   

[mopar_nut_440_6]

If you are that worried about it install a on demand hot water heater. It heats as you require the water but does cost a couple of grand to install. You have as much hot water as you wnt and never have to heat a tank of water not being used. I recently had to replace my tank but did not install this as my kids would be taking hour long showers every day!

[1969chargerrtse]

If you are that worried about it install a on demand hot water heater. It heats as you require the water but does cost a couple of grand to install. You have as much hot water as you want and never have to heat a tank of water not being used. I recently had to replace my tank but did not install this as my kids would be taking hour long showers every day!

This is what I have in my home, The furnace holds a small amount of water and as we use it, it runs through a coil heating up, you can run it all day and never run out.  Then there is a mixing valve after it comes out that I can adjust to cool it more or leave it hot.  I like it, It's not as consistent as a big ole water heater but it gets the job done.

[dodgecharger-fan]

all it is just a thermostat. All it does is keep water at certain temperature. Would it cost more energy to keep 60 gallons of water at 120F or 90F, makes any sense?

No. that's what the water heater does.

The idea behind this is to allow the heater to be set higher in order to avoid growing a science project in the tank BUT blend some cold water into the line when there is a call for hot water so as to reduce the temperature of the water going out to the fixture.

It has nothing to do with saving money - in fact, it actually uses more energy.

The point is that a lot of municipalities are moving toward a code that will require the higher temperature in the tanks and these valves for safety.

So, the idea of lowering heater temperature to save money may become a moot point in the future.
If you buy in to the reasoning behind all of this - preventing legionnaire's disease - then it's already a moot point and you'll want to crank up the temp on your heater and install one of these.
If you don't buy into it right now, the government might come along and tell you to change your mind.

I don't want to get into an argument as to whether it's right or wrong. I'm just offering up the info so you can make your own call.
There's a reason that water heaters can be set to such high temperatures - too high to use directly. It's to kill the cooties inside the tank that can grow in warm, moist environment.