I have a WF7 in southeast MI in a 2250 sq ft 50 year old house. There are cathedral ceilings and a fair amount of glass. I’ve been retrofitting with new windows and better insulation, including closed cell spray foam where I can. The roof unfortunately has minimal insulation due to the home design. The Aux Heat will kick on with stat set at 70F when it’s in the mid 20F’s. Is this normal considering the above? When does your Aux Heat come on?