Dining Room, Table, Chair, Pendant Lighting, and Concrete Floor The downstairs area is floored in polished concrete, and flanked on the north side by huge full-height windows through which passive heat is gathered. The majority of the winter heating, however, is from a ground source heat pump that uses the latent energy in the earth — a relatively new solution in New Zealand.  Photo 3 of 9 in This Kid-Friendly Home is Full of Surprises