The crossover point in any grid that has significant gas presence - which is absolutely ANY "renewable" grid- is not a COP of 2. It is 3. That is, per this graph, 5 C. A temperature at which if you do things right, process heat (ovens, showers, humans) should be supplying enough of the required delta T that you really don't need to spend a lot with any energy source. And that's the marginal crossover point, not the "I need to remodel my home" crossover point.
Just... what happened to the meanest part of self-criticism that science bodies used to have? Do they think other people won't ask questions? Because I'm sorry, they do so a great deal more now than ever. Many of those "questions" are stupid. But some are not, and shouting them all down means people should distrust you.
Calculations should include not just the CO2 output per kWh of today's grid but also the CO2 output per kWh of the grid over the 20 year expected lifespan of the heat pump. Most developed countries have committed to a net-zero grid by 2035. Even if you believe that they'll break that commitment, they will likely get close.
Comment confused me a little bit (won't heat pump heat be reused too?), until I realized that you were factoring in gas-to-electricity efficiency. That makes sense.
Just... what happened to the meanest part of self-criticism that science bodies used to have? Do they think other people won't ask questions? Because I'm sorry, they do so a great deal more now than ever. Many of those "questions" are stupid. But some are not, and shouting them all down means people should distrust you.