In his recent column, Andy Staatz misses the main point of reach codes (“Reach codes: Breaking down the data reveals some surprises,” Aug. 26). Reach codes are about the future, not the present or the past. Homes built today will last 50 or more years, and it is important that they be designed to take into account the projected changes for that future.
Staatz claims that 50-60% of California’s electricity comes from fossil fuels, but this is incorrect. The California Energy Commission reports that nearly two-thirds of the state’s electric power was carbon-free in 2019. He may have confused renewable produced electricity with carbon-free electricity. Renewable power in California excludes large hydro and nuclear power. California is on a path to 100% carbon-free power by 2045.
Some of the other numbers cited by Staatz are also misleading. For example, he states that 3-10% of energy is lost in the walls of our homes, but this is not attributable to electric losses, which are probably less than 2%. Because of these and other questionable numbers, his conclusions on electric heating are not correct.
Staatz quotes some efficiency data on electric water heaters and furnaces, but he ignores the better technologies that are already available. Electric heat pump furnaces and water heaters are five to 10 times more efficient than conventional resistance heating that has typically been installed in homes. These systems are projected to be even more efficient in the future.
We installed an electric heat pump heating system in our Los Altos home a few years ago, and I have tracked the results. During the winter, we used to use approximately 450 therms of gas to heat our house, costing approximately $750. With the electric heat pump system, we use an estimated 1700 kilowatt hours, costing approximately $300. In addition, we get air conditioning, which has been a blessing with the recent smoky air and high temperatures. This system is also quieter than our gas furnace was and keeps the house at a more stable temperature. We also recently installed a heat pump water heater and are seeing a similar percentage savings.
It is also important to note that the standard Annual Fuel Utilization Efficiency (AFUE) method for measuring gas furnace efficiency was created in 1993 by the gas furnace manufacturers and only measures the efficiency of gas combustion within the furnace. Thus, gas furnace efficiency ratings are only calculated on the amount of energy in the gas that is converted to heat inside the furnace. Staatz correctly cites that the AFUE for home gas furnaces is 80-95%, but this does not include losses that occur in moving the heat from the combustion chamber through the heat exchanger to the area where it is used, or losses to the furnace’s environment, such as a cold garage. It also does not include the electric power losses to operate the furnace blowers and the controls.
California is clearly on the path to carbon-free electricity, but there is currently no viable path for gas furnaces and water heaters to become carbon-free. So, now is the time to move to electric space and water heating, as systems installed now will still be operational in 2045.
John Petro is a Los Altos resident and electrical engineer who has spent much of his career focusing on energy efficiency.