Thanks for the link! I have Fujitsu which I run when outside air is above 40F. Looks like it gets an amazing COP of 5 to 6, far exceeding the spec. I have tankl

Thanks for the link! I have Fujitsu which I run when outside air is above 40F. Looks like it gets an amazing COP of 5 to 6, far exceeding the spec. I have tankless hydronic heating using natural gas for most of the winter, but it couldn’t quite heat my house when temps dropped to 5F.