Aug 12 2020

OPINION: To Help the Climate, Support the Proposed Reach Codes

Electric heat pump, water heater, and furnace make sense from a state-wide CO2 accounting viewpoint.

First, let us be clear that the proposed codes address only new constructions or large renovations. Of course, once adopted they will set the direction for future expansions of their applicability.
The CO2 emission impact of installing electric heat pumps in place of natural gas heaters (whether for new structures or as replacement for existing natural gas installations) is positive. Note that I am addressing only CO2 emission, not capital or gas/electricity costs.
At the State of California level, the sources of electrical energy fluctuates during the day as shown in the figure below for May 24, 2018. Note the large drop in available renewable energy (wind and solar) at night, in the morning, and in the evening.

Today there is a lack of storage facility for electricity generated by renewable energy to enable shifting that energy from the time it is produced during the day to the time it is needed that same day in homes. So potentially an electric heat pump will be fed by electricity generated by a natural gas power plant because of the unavailability of any of the other sources at the time the pump is running. However as a first approximation, the amount of CO2 emitted by the plant is the same as from burning natural gas at the home to generate the same amount of heat. This is because an electric heat pump furnace has a coefficient of performance (COP) of 3 in our Bay Area climate (meaning one watt hour of electrical energy generates three watt hours of heat) and natural gas power plants have an efficiency between 30% and 38% in generating electricity.

The proposed Reach Codes may want to favor the installation of heat pump water heaters over heat pump furnaces because the hot water in the tank can be a store for renewable energy, provided that the heater is well insulated and equipped to draw electricity mainly during daytime. Such policy has the added advantage of soaking up the excess renewable electricity that is curtailed many days during the year, as documented by the California Independent System Operator (CAISO).
The COP of a heat pump may drop below 3 during cold winter nights, but this is compensated on average by better performance in the summer. Utilities charge about three times more per unit of energy for electricity than for natural gas, because electrical energy can be put to work without increasing entropy (disorder). This rate ensures the same operating cost for both heat pump and natural gas furnaces in the Bay Area climate. The capital cost on new installations is higher but can be mitigated when combined with solar panels.
Bernard Pech, Piedmont Resident

7 Responses to “OPINION: To Help the Climate, Support the Proposed Reach Codes”

  1. The proposed new “Reach Codes” treat renovations in the amount of $25,000 as large renovations.

    Our homes are very valuable assets…I encourage every homeowner to read the proposed ordinances for yourselves at:

    My concerns related to these ordinances are not due to opposition to energy conservation or opposition to reducing GHG (Green House Gasses).

    Here are some of my concerns with proposed ordinance 750.N.S

    I find the seven “Energy Efficient Measures” (EEM) described in Section D of Ordinance No. 750 N.S. are too broad, and they lack dollar amounts limits.

    Section D specifies that the EEM must meet specific criteria of the 2019 California Energy Code Sections (155.2(b)1E, 150.0(d), 110.9(b)4,150.2(b)C, 150.2Hiii(b) or 150.2Hii(c), and the Green Building Standards Code 403.3, Having read these proposed regulations at: and I feel that the honorable citizens of Piedmont deserve the time to become fully informed on these changes. I think most people will agree that these EEM’s are excessively burdensome for renovations of $25,000, and in many cases too burdensome for $100,000 renovations.

    And why in the name of reducing GNG, should legislation requiring all household toilets to be 1.28gpf (gallons per flush) and faucets at 1.2 gpm (gallons per minute)

    In online discussions at the “Nextdoor” social site for Piedmont, it has been reported that the Piedmont Planning Commission had NO FORMAL PARTICIPATION in developing these codes.

    Section 4 of this ordinance makes changes to household electrical provisions that are not even associated with renovations…this section clearly needs clarification and input from Piedmont’s Planning Commission.

    Section 5 mandates that all new construction shall be “All Electric”. Some concerned citizens perceive this would apply to detached ADU’s (aka “in-law units”). Given how little new construction is likely in Piedmont, it seems this provision would make an inconsequential reduction in GHG or net energy reduction. Is the result really worth the burden?

    Here are some of my concerns with proposed Ordinance 751 N.S.

    I feel that some dollar limit on the “Home Energy Audit” requirement should be stipulated. In my research of nearby Home Energy Auditors, I found only 3 companies. I don’t know these companies, but it seems intrusive to me to require citizens to have an unknown company inspect one’s entire home for an energy audit… Especially when the biggest culprits of wasted energy are commonly known: single-pane windows, poor attic insulation, leaky HVAC ducts, and poorly insulated hot water appliances.

    I’m aware that a certain dedicated population of Piedmont’s residents have been working on reducing Piedmont’s GNG and energy consumption for many years. Their goals have merit, but the effect of these ordinances are far too broad to enact without a more comprehensive understanding and acceptance of the impacts by a much larger portion of Piedmont’s residents.

    In summary, the proposed “Reach Codes” need review by the Piedmont Planning Commission and more citizens before they are implemented.

    Dai Meagher, Piedmont Resident

  2. Social Security single home owners cannot afford this expense especially if they need to change bathroom and kitchen to handicap access. Too expensive to convert water heater and stove. Elderly homeowners should be exempt.

  3. I think Planning used to waive setback rules when wheel chair ramps and other accommodations were being added. Perhaps that would apply here as well.

    There is no requirement in the reach codes to convert your stove or water heater.

  4. Unfortunately, the reasoning in my post might be flawed. I forgot to take into account two facts: the high efficiency of modern natural gas home furnaces (up to 90% with regard to generating heat) and the so-called cogeneration technology. I need to think this through again and will correct my initial post if needed later.
    Refer to

  5. Well, my reasoning is correct! Taking into account the inefficiency of home natural gas furnaces as well as the loss of energy in transporting electricity (10% to 18% depending on the distance) does not change the conclusion.
    The use of micro-cogeneration technology in the home with natural gas as a source may be worth considering in the proposed Reach Codes. The reason is that the heat thrown away in a utility natural gas power plant (that cannot be utilized to make more electricity due to Carnot principle – law of thermodynamics) can be used in home through a heat exchanger for example to heat a pool.

  6. Thank you Bernard. You clearly know a great deal on this topic. I’m going to try and read more about micro-cogeneration…and the “Carnot principle”

    I maintain that if Piedmont residents reduce their overall carbon production (e.g. energy efficient windows, improved insulation, less travel to Tahoe, less recreational air travel, cessation of gasoline powered leaf blowers) that will provide the same or greater benefit of removing natural gas energy in Piedmont.

  7. I believe the climate change issue is real. I am concerned for the future of my four grandchildren. At the same time it seems to me that many decision makers do not know what they are talking about on energy generation and consumption as they are driven by political considerations and “politically correct thinking”. Being retired I feel the need to think the issue through myself.

    Any proposed local and state level regulation should first be looked at from the point of view of what I will call “CO2 accountability”. It would not make sense to change the code in our City for new constructions or renovations in order to reduce that city CO2 footprint, for example by replacing the use of natural gas for heating water and the home with heat pump technologies, if the same amount of natural gas or even more were burned by State Utilities to generate the electricity to run these heat pumps. So “CO2 accountability” for our City is about making sure that new policies do not shift the “CO2 pollution” to the State level.

    I consider cost to the homeowners of any new local code as a secondary issue. The cost has two components: capital and operational. Both are affected by policy decisions taken by the Public Utility Commission regulating PG&E and as well as laws passed at the State level. I leave the consideration of cost to our elected Piedmont officials as it is clearly a political issue.

    I do not mind discovering that I am wrong and correcting my position. I was pleased to see that at the beginning of his term our Governor decided to reconsider whether to keep on building the electrical high speed train between San Francisco and Los Angeles. As far as I know, we are building a regional train service in the Central Valley, and hopefully will remove all the crossings between San Francisco and Palo Alto to make that CalTrans service what it should be in our 21st Century.

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