How often does your auxiliary heat run? (I'm guessing heat strips because if your NG service is shut off, it can't be dual fuel unless you have a propane tank)
Our variable speed central air-ducted heat pump lets us watch in real time equipment operating status including at what variable percent the compressor is working. We have never gotten close to needing auxiliary heat. Last year (2021) of the 1874 kWh we used for heat pump home air heating, only 7kWh was used from electric resistance heat. However, all of that 7 kWh was to defrost the coils on the coldest winter pre-dawn mornings.
Ashamed to concur (and provided the guess-o-meter on our heat pump unit is fairly accurate).
I have long considered a wifi valve device put inline with the hot water heater that could be controlled via an app on a parent’s phone. When triggered, it would gradually turn the hot water off. Maybe over a 3 minute period, signaling to the teen in the shower that it’s TIME TO GET OUT.
Did you go with electric auxiliary heat instead of a gas furnace to avoid minimum bill charges on gas? Currently I am looking at installing a dual fuel system and my water heater still runs on gas. And I probably won't get a heat pump water heater until they do the sensible thing and put the evaporator and compressor unit outside the house so it doesn't make so much noise inside. You can easily hear a compressor running in the garage but not one that's outside.
thats basically how it works now in CA. Once you hit net zero, you get compensated at the wholesale rate
I missed that comment, and I concur. I'm on such a plan now, and any excess beyond offset usage is paid at a pittance compared to the actual generation.
We had NG turned off at the meter a few years ago but that was not the main reason. We did hope to avoid minimum NG bill charges, but that was mostly a wash as California perversely gives one of the clean energy rebates through having NG service which mostly erased the benefits of losing that charge.
Your sig says SF bay area. Your winters likely are even more mild than ours (we don’t get more than a very brief light snow every few years and freezing temps are not particularly common nor have I seen if colder than 25°F and only below freezing temp some winter days for a few hours before dawn). I would recommend you consider not going the dual fuel route.
This would certainly help with noise inside, but you would lose efficiency by moving it outside and it would also be more prone to rusting. We run our heat pump water heater only during off-peak hours. That also means running it sometimes when it is quite chilly outside, but invariably it is much warmer in the garage then.
No, it's 12 month rolling average which was like $0.04/kWh on my latest statement and calculated at your annual true-up statement.
I'm a net producer and get compensated at ~$0.03-$0.04/kWh for my excess production no matter what the wholesale prices are. I adjusted my thermostat down to 76F this summer since it is worth the small amount I loose in compensation.
I have an existing gas furnace. The gas hookup is already there. And the quote I got for the 80 AFUE furnace is cheaper than the quote for an air handler plus heat strips, which would be a few hundred dollars more, believe it or not. I'm not sure if that's because they'd have to install 240V power to the air handler and heat strips or if gas furnaces are just that cheap, but that's the quote I got. Dual fuel is more flexible and has a lower carbon footprint too, assuming the electricity is being generated by fossil gas at the power plant. Is that a good assumption on the coldest nights (no sun, calm wind)? I think so, until we start using nuclear breeder reactors, but those should kick in after we have plenty of storage because they can't ramp up and down quickly like fossil gas plants can. So anyway, my conclusion is that dual fuel is probably better for the environment, regardless of what the people at CARB just said about gas furnaces.
Well ideally, compressor and one evaporator outside, and another evaporator either in the garage or in the house (for times you want the house cooled). There are reasons to take heat from the house or garage but doing it when you need the house heated is counterproductive.
Agree, you might be able to take advantage of current and future price arbitrage with a dual fuel system if economics are the primary driver and continue to pencil out.
We were concerned about that possibility but in our case (PG&E) + home solar PV that proved to be far from the case:
Yes, Diablo Canyon is the only nuclear plant in California and PG&E owns it and takes (it appears full) accounting credit for it.
It was set to close in 2025 but within recent months legislature has been pushing to keep it open five years longer. Diablo Canyon produces 2,250MW, nearly 9% of California's electricity last year and ~15% of the state's clean energy production.
