This past week, California passed future changes to the energy code for buildings, including a requirement for all new homes (built in 2020, so not tomorrow!) must be net zero energy. This is a big deal, and has a number of people asking about cost effectiveness, feasibility, and what this means for the increasing duck curve. The real question on my mind is What Can I do to My Old House to not get left in the dust?!

My prediction of the future is all electric homes, in California at least, will start to be lower cost to operate than ones with natural gas and electricity. There may need to be some combination of solar+storage to make new homes more efficient and grid citizens (shout out to NBI on GridOptimal, coming soon…). Stick with me here, if I want to keep up with the Joneses down the street building a new all electric, net zero house I have some work to do. As an engineer, I started by outlining the challenge and then made a list.

Challenge: Electrify my house to be solar and EV car ready!

My Current House

As something I already take care of and use, I have decided to start with my house and take steps to electrify the base first before adding on bells and whistles.

• City: Santa Rosa, CA
• House: 2,000 sf + 250 sf yoga room (in detached garage)
• Central furnace with AC (DX outside unit)
• Gas hot water tank
• Gas dryer
• Gas range for cooking
• (no heat) in yoga room (wife not happy)

List of Changes

• Change the stove to induction (run new high voltage line)
• Change the dryer to a heat pump dryer
• Change the DHW to a heat pump
• Change the whole furnace system
• Add a mini-split to the yoga room
• Upgrade electrical panel
• Install solar system

Confronting the Heat

After outlining my list it is becoming very real how hard this will be. The biggest challenges are finding cost-effective ways to switch my whole house to a new source of heating. So far I have thought of 3 solutions:

1. Replace my furnace AC with a single-zone heat pump, re-using most of my duct work ($$)
2. Install a new VRF system with a few zones and a central 4 ton heat pump ($$$)
3. Install radiant tubes under my house in the joists myself, and back it with insulation, and connect it to an air-to-water heat pump ($$, +++ time)
4. Retrofit in ahhm radiant panels in place of a few sheet-rock panels in each room, running pex pipe back to an air-to-water heat pump ($$$, my dream, + so much time)

Part of me really wants to rip apart my house and put in radiant while the other part of me doesn’t want to spend the rest of my life fixing my house. If anyone has any recommendations on a system they like, or a heat pump with nice features that is quiet, I would love to know more!

For now, I am going to start with the induction stove and heat pump dryer, plus the mini split in the yoga studio. They are the easy ones, yet still will require running a bunch of 220 volt lines to make it all work. Likely by the time I am done, my panel and connection to the street will need some attention. The hidden cost of retrofitting old homes to all electric is paying to replace the natural gas piping infrastructure. Though even if it costs slightly more than I save, it is a very powerful way to take action and do my part to decarbonize the grid. I think of it as starting with the part of the grid I manage and building out from there.