zlacker

1. No, absolutely not. Why would you settle for COP=1 when you can have COP>1?

2. The electrical to heat conversion efficiency is indeed 100% regardless of the temperature of the resistor. And if you're putting out 1000W, then all input losses are also identical. If you put a 1000W light bulb in the middle of your room, or 2 of them but run both at 500W, you'll get EXACTLY the same heat output in your room, but the single bulb is much hotter.

>>coryrc+(OP)
1. Are there not scenarios where it drops below 1? The stats for them always seem optimistic scenarios given what i hear from people during winter cold spell in houses that aren't absolutely perfectly insulated. If your water term needs to remain above 70C and it's starts freezing hard outside during winter when that COP starts to matter the most for example.