This is not theoretical: my heat pump purchased in 2021 worked well for four straight days of below 0F. Kept our temp at 68 inside. We live in an old home from

This is not theoretical: my heat pump purchased in 2021 worked well for four straight days of below 0F. Kept our temp at 68 inside. We live in an old home from 1917 with poor insulation between the brick exterior walls and drywall.