In his Jan. 31 guest column ”All-electric rule: Costlier homes, worse efficiency,” David Murphy discusses the wisdom of Northampton’s new fossil fuel-free construction ordinance and asks the question “Am I missing something?” The answer is yes.

First, his statements about the electricity generating resource mix are misleading. His statement “About 75% of the electricity in the grid comes from non-renewable sources, mostly natural gas” might lead one to believe that only 25% of the mix is fossil fuel-free.

Instead,consider that with the temperature in Northampton at 26 degrees at 8:06 on the morning of Jan. 31, the resource mix as reported by ISO New England included 45% natural gas with less than 1% coal and less than 1% oil. The remaining 54% was from a mix of imports (mostly hydro from Quebec and New Brunswick), nuclear and renewables. These are systemwide numbers, not specific to any one home.

More importantly, he misses the fact that heat pumps don’t heat air. They move heat from one place to another.

Heat pumps can be highly efficient; at times moving nearly 5 kWh of heat for every 1 kWh they consume, depending on the model and ambient temperature. A 2023 study of heat pump efficiency reported that tests in Finland showed that even at 0 degrees Fahrenheit, air-to-air heat pumps can move more than twice as much energy (heat) than they consume. Maybe the author would have come to a different conclusion using a more accurate set of assumptions.

Aldo Tiboni

Florence