> This is borderline a tangent, but I think manufactures should be required to provide data regarding efficiency at specific temperatures. These are available,

> This is borderline a tangent, but I think manufactures should be required to provide data regarding efficiency at specific temperatures. These are available, and there are standards for EnergyStar approval and for being able to call yourself a "cold climate" air source heat pump (ccASHP): * https://ashp.neep.org/#!/ https://ashp.neep.org/#!/ * https://neep.org/heating-electrification/ccashp-specification-product-list https://neep.org/heating-electrification/ccashp-specificatio... Mitsubishi data sheet with COPs at various temperature: * https://mylinkdrive.com/viewPdf?srcUrl=http://enter.mehvac.com.s3.amazonaws.com/DAMRoot/Original/10006%5CM_SUBMITTAL_MSZ-FS12NA_MUZ-FS12NA_en.pdf https://mylinkdrive.com/viewPdf?srcUrl=http://enter.mehvac.c...