#### Transmission Heat Loss through Building Elements

The heat transmission through a building wall or similar construction can be expressed as H t = U A dt 1 where H t = heat flow Btu/hr W J/s U = overall heat transfer coefficient U value Btu/hr ft 2 o F W/m 2 K A = wall area ft 2 m 2 dt = temperature difference o F K The overall heat transfer coefficient the U value describes how well a building element conducts