mp246 t1_izxm2ql wrote on December 12, 2022 at 4:37 PM

Reply to comment by SynbiosVyse in Holy $#!^ Eversource by Xaphas

>They are bad in cold weather. You can't argue the physics of it. If you look at the efficiency curves the top of the line Bosch drops to 50% efficiency below freezing.

you really don't know what you're talking about. i can't find a bosh specific chart, but modern heat pumps can be ~200% efficient at 0F. and i'm talking about efficiency in the sense of units of energy in = units of energy out, not in a sense of dollars per BTU or whatever

>I'm not sure what variables you speak about, this is a fairly controlled experiment.

you really, really don't know what you're talking about.

SynbiosVyse t1_izxscp8 wrote on December 12, 2022 at 5:18 PM

The marketing of COP (coefficient of performance) being greater than 1 for heat pumps is exactly the kind of marketing they want you to believe as being important. COP is a good way to compare heat pumps to other heat pumps, since standard energy-in/energy-out doesn't make sense. If you're talking about relative efficiency, central heat pumps are going to drop to about 50% in terms of the amount of electrical power they use for the amount of heat they produce. For example, if it uses 2 KWh to raise 1 degree from 54 to 55 F, it will use 4 KWh to raise 1 degree from 10 to 11. Because of this sharp decrease in efficiency you're going to be paying up the nose in electricty compared to a furnace or boiler which efficiency curve is completely agnostic to the temperature outside.

mp246 t1_izxu5y8 wrote on December 12, 2022 at 5:30 PM

everybody already knows it takes more energy to heat something as it gets colder and colder outside dude. and you still don't understand the difference between relative efficiency and absolute efficiency, you keep mixing them up, and then on top you that you mention absolute costs when i specifically called out the difference in the previous post.

when you talk about your gas boiler vs your heat pump, what does it cost you, in terms of dollars, to get 1 degree of rise out of each? post that, along with the manual j for the respective heating zones, and then we can start to get a rough idea of what is more efficient in terms of absolute costs. until then, you're just talking out of your ass