A positive addition to this design might be trees between houses to shade east and west walls during summer. These could be located to avoid shade on the collectors. In temperate climates, deciduous shade trees are best for any location on the south side of a house. However, because the most effective shade will be by trees close to the house, safety and growth rate are of paramount importance in selecting a shade tree species. In warm climates with little heat energy demand, the main requirement for a shade tree is high crown density and a tree that can be pruned to allow airflow around the house.
Wind also carries heat to or from outside building surfaces by convection.
In winter, convection is generally less important than air infiltration, and is less important for walls than for windows. However, especially in summer, surfaces heated by the sun become warmer when wind speed is low. Hence, wind reductions in summer can lead to increased energy use for air conditioning. With wind direction perpendicular to a long windbreak, reductions of 30 percent have been measured as far as 15 times the height of the windbreak downwind. Because even single rows of dense conifers can cause large reductions in wind speed, effective windbreaks can be planted on relatively small house lots.