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Old 11-24-2022, 07:02 PM   #8
SailinAway
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Quote:
Originally Posted by ITD View Post
I think heating water with oil is cheaper than using electricity. I looked at the link you provided, it looks pretty much like I'd expect. I think the default efficiency for oil list there is too low. I changed it to .85, unless you have a really old boiler yours is probably closer to 85% than 60 % too.

For 5 gallons a day, I got $65 for oil and $86 for electric.

The thing about using your boiler is that the boiler temperature needs to be kept hot enough to give hot water in a reasonable time. This uses additional oil versus what it would take to just heat the 5 gallons a day. I'm wondering if your link takes this into account. I actually think it may based on my original guess of 1 gallon a day.

"In the noise" means that if you could instantly heat 5 gallons of water with oil and not have to keep the boiler hot, it would probably take a gallon of oil a week rather than every day.

But in the end these are just estimates and the difference in cost negligible between oil and electric. It would take far too long to break even on the cost of changing over to justify it. I would just turn the electric heater back on and forget about it until the tank fails.
ITD, thank you very much for taking a look at that link and running the numbers again. My boiler was measured at 83% efficiency last year. There would not be any cost to change between oil and electric. I have both the tankless coil and a water heater installed. The aquastat on the coil is disabled.

I reread all the replies in the other thread about saving money on heating water and did some more research. I'm leaning toward putting a timer on the water heater and running it 1 hour a day. I'm thinking this might be the simplest and cheapest solution. The water heater is 4000 watts, or 4kWh per hour = 120 kWh per month x 17 cents per kWh = $20 a month.

Thoughts about that idea?

An on-demand system installed in the upstairs bathroom makes the most sense in terms of conservation of water and electricity and shortest distance to the shower, but it's the most expensive and least practical solution, involving opening the wall.
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