Water heater timer - what's better

[roperman]

Here's my setup: a 12 year old forced hot water oil boiler, with a gas conversion burner, and connected to that is a 40 gallon indirect fired water heater. We've been heating our house with a wood stove for the last two years, so all the boiler does is heat our hot water and serve as a backup for our wood stove.

When the plumber installed the water heater, he turned the low point on the boiler all the way down. The boiler kicks on when the water in the boiler goes below around 65 F degrees. High point is 160. Water heater is set at 127 degrees F, which gives us 120 degree water at the faucet. The heat loss for the water heater is 1/2 degree per hour.

The water heater calls for heat when the temp goes 10 degrees below the set point. So the boiler may sit for hours without calling for heat, so the boiler temp goes down to room temperature again. So for our hot water, the boiler is heating its own 6 to 8 gallons of "boiler" water to 160 degrees in order to heat the water in the water heater. That seems like a lot of energy going in to heat the boiler up every time we draw hot water.

To remedy this, I installed a timer that turns on the water heater once a day for an hour. The 40 gallons of hot water gets us through the day (so far, but I just installed the timer last weekend). My friend says this won't save any energy, because warming up the hot water tank from a low temperature will take more energy than heating it up throughout the day, where the temp differential is lower.

A drawback is that the hot water controls will be turned on daily instead of being left on constantly, which may reduce its life somewhat. It's got a solid state control unit with a LED control panel.

I could get a device that measures the amount of time my boiler kicks on to find out which way is more efficient, but before I shell out for that, I thought I'd see if anyone had any ideas. Anyone have any guesses which way is better? Thanks!

Jay - jayroperman a t h o t mail dit c om

[hallerb]

I would install a standard water tank since you never run the boiler for heat.........

Nows here a great question that may cause you grief:)

How many hours a year do you spewnd cutting hauling stacking splitting the wood for your stove? add bought firewood if you do that.

Now compare your cost of work to the cost of fuel for your regular boiler.

even with free firewood every person I EVER asked isnt really saving much money.

So please supply your numbers:)

[trainfan1]

Don't forget maintenance & chain sharpening(+ materials for this), which I do on my ~11 chain saws, & purchase of saws, & a 20 ton wood splitter(same issues), fuel, repairs, all on top of your time.

Makes a windmill look better all the time...

Rob

[Bob F]

Your friend is wrong. It uses the same enegy to heat the water, and you lose less heat when the water tank temp is lower. It may not be a big difference though.

Bob

[Jordan]

Good point, but you could also factor in those that go through the splitting and stacking don't require a $500 per year gym membership ;-)

Then there is that whole fund>> Here's my setup: a 12 year old forced hot water oil boiler, with a gas

[roperman]

Tell me about it. It does take a lot of time, but we always do tell ourselves that the wood thing is our gym membership. We've been scavenging the wood so far, so the wood we burn just costs us our labor. I'd love a windmill, but our lot wouldn't work - too many trees, plus our kids can't curl up in front of the windmill on a cold night. They love the wood stove, and it usually usurps the TV which is almost worth all the work. The only reason I'm able to do this is because my wife helps me split, stack, and scavenge. If she wasn't into it, it never would have happened.

This spring she got a tree company to dump about 4 to 5 cords of red oak on our front lawn, big heavy 36 inch diameter stuff which we finally just finished. Good stuff, but hard to work with. Last week she got another company to dump 2 cords of sugar maple on the same spot, so we should be all set for next winter. Just have to get out there and start bucking it up and splitting it. We went in on a Troy bilt 27 ton splitter with a neighbor last spring and have been very happy with it.

I ordered a watt-hour meter that I'll install on the boiler. By running it either way (on all the time vs. on the timer) and comparing the electrical usage, I should be able to tell which is cheaper. I agree that if I'm not using the boiler, then a stand alone water heater would be better. The unit is three years old and I can't justify the $$$ for a new heater.

Jay