G
reenhouse Gas Reductions by Vintage of Home
Metric Tons P ercentage
Approach Pre-
1978
1978-
1991
1992-
2010
Pre-
1978
1978-
1991
1992-
2010
Heat pump & new air handler (no furnace) 1.30 0.97 0.84 37% 32% 30% Heat pump with existing furnace as backup 0.94 0.69 0.63 26% 22% 22% Attachment 4
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