So far the house has been cosy warm, an early indication that having lots of north facing windows and good insulation makes a big difference. The picture shows the midday sun streaming into the family room heating the insulated floor slab.
We haven't had any really cold days yet but early indications are we will be very comfortable.
Above is the graph of the past 7 days.
Blue is the inside temp; averaging about 21, max about 24 and min about 18 deg.
Green is the floor slab, hovering around 19 to 20 deg.
Cyan in the temperature in the roof space; peaking at almost 35 deg on the sunniest day the dropping to the same as the outside temp (red) during the night.