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SynbiosVyse t1_j09tw0m wrote

Reply to comment by modernhomeowner in Is it more efficient for me to heat my home with my ductless mini split or my old boiler? by CatoFriedman

I think 65% efficiency for an old boiler is even a very low estimate. Boilers have been at least 80% for a very long time.

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modernhomeowner t1_j09uy5g wrote

Well, a higher efficiency makes oil an even cheaper proposition over electricity. The boiler itself may be rates at 80% but other system inefficiencies also take place, it only operates at maximum efficiency right after cleaning and gradually gets worse. I've pretty much calculated my system at 72% and that's with a 12 year old boiler. But if this person gets 72% or 80%, you can recalculate the math and it's going to result in higher equivalent oil prices, meaning you'd want to use oil even more often then electricity.

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SynbiosVyse t1_j09zlt1 wrote

Yeah I agree. I made a similar post a few days ago saying my gas boiler seemed more economical to run than my heat pump after some anecdotal testing and I got eaten alive.

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modernhomeowner t1_j0a09jp wrote

Gas as in Natural Gas? Yes, that's much cheaper if you have the same electric rate as the OP. Much cheaper! Assuming again a bad efficiency of 80%, a 2.6COP, natural gas would need to be under $4.35 a therm, which Eversource is $2.51. if you have a 92% efficiency, you'd be at $5 equivalent, so natural gas would be half the cost of the heat pump.

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Kspoonie t1_j0batjr wrote

OP has a System 2000 which is the only high efficiency oil boiler I know off. I’ve seen them upwards of 90%, even old ones. He’s probably better off getting a System 2000 Qualified technician to tune it up and run that. Pricey unit for sure.

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