Hot water heater question

Sport45 wrote:

ZOSO wrote:

Sport45 wrote:

ZOSO wrote:

Sport45 wrote:

csamayfield55 wrote:
I don't have any exact numbers here but from someone who works around commercial AC and heating systems here is my thoughts. You can either take it or leave it.

It takes WAY more BTU's (British thermal unit's) to heat water from ambient temperature to say 120 deg. than it does to maintain that temperature for a period of time. The water heater may cycle 4 or 5 times a day for short periods but it is not nearly as much heat energy than letting it cool and then reheat even 2 times a day.

Same for your AC unit's. If you let your rig heat soak till it is too hot to bear inside then turn on your AC it will take much more energy to remove that heat than if you set your stat at a comfortable level and maintain that level.

Chris

Sounds good on the surface, but I ain't buying it.

The heat loss from the hot water tank is to the atmosphere through the insulation on the tank. Heat loss is a function of the temperature difference so the colder the water is the less btu's per hour are being lost. Keeping it hot 24 hrs/day means you are radiating the most heat to the atmosphere and that has to be replenished with propane or electricity. Allowing it to cool between uses radiates less heat and uses less energy in the long run. (Even if it seems like it's firing longer).

Well, I'm going to agree to disagree with you on this Sport45. I'm definitely buying what Chris is selling!

As you wish.

But unlike speed limits, it's hard to break the laws of thermodynamics. :)

One would have to know how much heat is radiated to the atmosphere with the heater firing however many time a day, to maintain temperature VS. how much heat is radiated to the atmosphere with the heater firing however many times a day to heat water from air temperature to usable hot temperature. Obviously the heat source would run longer to take water up from air temperature.

Throw in all the variables and personal use habits...Well, it's not just as simple as a science lab law. A control experiment doesn't really indicate how things would pan out on a personal use level.

I wonder if anyone flips there HW heater on and off in their house?

As it's been mentioned before we're not talking gobs of money so I'll agree to disagree. It's not worth the effort to explain the science.

And no, I don't turn off the water heater in my house. I'm happy to pay the extra to have hot water on demand. I just wish the builder hadn't put the thing in the attic and run the line three times around the house before feeding the master bath... It's a long wait for hot water where we would really like it the quickest.

I'm in complete agreement with you there Sport45! Certainly not enough saving or loss to bother monitoring or worry about or flip the HW on and off ad nauseam. Unless that's an interest for a person, then they should do so.

You definitely don't need to take the time to explain any science to me. I follow the principles of thermodynamics. I'm saying in the real world, there are just too many variables to give a decisive, sweeping answer to the OP's question. Way too many variables. For my personal situation, I'll turn on the HW or heat or AC and leave it do it's job.

You are probably already aware, you can get a recirculating pump for your hot water issue at home. Last I checked them out, they were pretty hard on electricity. Could flip it on and off though.....:hHmmmmmm.....I wonder......Er nevermind.

Nice chatting with you about something neither one of us could really care less about Sport45 ;) All the best!