Ex.: During a cold winter day, wind at 55 km/h is blowing parallel to a 4-m-high and 10-m-long wall of a house. If the air outside is at 5C and the surface temperature of the wall is 12C, determine the rate of heat loss from that wall by convection. What would your answer be if the wind velocity was doubled? Attic space Air 5C 55 km/h 4 m 10 m 12C