Table 5.

All-year effects of trees on energy use for heating and cooling. Energy use is for houses with vegetation compared to the same house in a large open space.

Study	HDD-CDD^a	Energy use^b
			%
Measured in mobile home
In deciduous woodlot in central Pa. (13)	+5280	−24	–
Computer modeling results Heavy deciduous shade on one-story frame house in Orlando, Fla. (5)	−2490	−15	−128
Row of trees 15 feet to south in Calif. (48)
Conventional house
Palm Springs	−2440	−7	−60
Truckee	+8170	+4	+38
Solar house
Palm Springs	−2440	+1	+5
Truckee	+8170	+25	+88

↵a Heating degree days minus cooling degree days; negative numbers indicate more energy needed for cooling than for heating.
↵b Minus signs indicate energy saving; plus signs indicate more energy use.