Page 60 - Green Builder Nov-Dec 2021 Issue
P. 60
BUILDING SCIENCE
Innovative solutions for high-performance homes.
Electric
VS
Gas
CREDIT: ISTOCK/OLIVIER VERRIEST
WATER HEATING BY THE NUMBERS
Innovation, plus the BY SHERRY LISTGARTEN about 60 percent efficient. On top of that,
With colder weather coming, it’s a the grid suffers from transmission and
growing menace from good time to think about reducing our distribution losses. While the grid does
heating emissions. When we burn gas have some clean energy, solar power is
Climate Change, and oil to heat the air and water in our least available when we most need the
buildings, we generate about 10 percent heat (e.g., nights and winters). Given all
support conversion of our emissions in California and an of that, can it really be true that electric
even larger share in less-temperate heat has lower emissions?
from gas to electric states (for example, 25 percent in New Let me tackle that question by
York). How can we reduce our heating focusing on California, which relies
technology for emissions? One good approach is to use heavily on solar energy. There are two
electric heat pumps rather than gas- parts to the question. The first is, how
domestic hot water. based heaters. In fact, beginning in 2022 much pollution is produced in order to
the updated California building code get energy for heating (gas or electricity)
specifies these as the default option for delivered to the building? And the
space or water heating in each of its 16 second is, for each unit of electric or
climate zones. gas energy that gets to the building, how
Many building owners and contractors much heat can it produce? (That is, how
are skeptical about this. After all, they efficient is the heater?) The answers,
reason, modern gas furnaces are based on what is currently known, are
90 percent or even 95 percent efficient, largely inspired by a few presentations
while even the best combined-cycle gas by Martha Brook, a policy advisor to the
turbines used to generate electricity are California Energy Commission (CEC).
58 GREEN BUILDER November/December 2021 www.greenbuildermedia.com
