- 120% rule
- An electrical code rule that limits how large a solar breaker a panel can accept.
- AFUE
- The efficiency rating for furnaces: the share of fuel that becomes useful heat. An 80% AFUE furnace turns 80% of its gas into heat.
- Backup heat strips
- Electric resistance heaters inside some heat pump systems for very cold weather. Effective but expensive to run. More
- Base Services Charge
- A fixed monthly PG&E charge, about $24 for most residential customers since March 2026. Solar credits can't offset it. More
- CARE and FERA
- PG&E income-qualified discount programs.
- Community choice aggregator (CCA)
- A local agency that buys electricity for a community while PG&E delivers it: MCE in Marin and Napa, Sonoma Clean Power in Sonoma.
- COP
- Coefficient of performance: units of heat delivered per unit of electricity used. A COP of 3 means three times more heat than the electricity it takes.
- E-ELEC
- A PG&E rate plan designed for homes with electric equipment like heat pumps, EVs or batteries.
- EV2-A
- A PG&E rate plan designed for homes with an electric vehicle.
- Export credit
- What PG&E credits you for solar sent to the grid. Under the current Solar Billing Plan, it's usually far less than the price you pay for electricity. More
- HSPF2
- A heat pump's heating efficiency over a typical winter. Higher is better.
- kW (kilowatt)
- A measure of power: how much electricity something uses, or produces, at one moment.
- kWh (kilowatt-hour)
- A measure of energy: power used over time. Your electric bill is measured in kWh. A 1 kW heater running for one hour uses 1 kWh.
- Level 1 / Level 2 charging
- EV charging from a standard 120V outlet (Level 1) or a 240V charger (Level 2). More
- Load calculation
- A code-based method electricians use to decide whether a panel can handle new equipment. More
- Load management
- Equipment that automatically limits a large load, like EV charging, so the panel is never overloaded.
- Main breaker derate
- Replacing a panel's main breaker with a smaller one so a larger solar system can connect safely.
- Manual J
- A room-by-room heating and cooling load calculation used to size HVAC equipment correctly.
- Peak hours
- On PG&E time-of-use plans, 4 to 9 p.m. every day, when electricity costs the most.
- PSPS
- Public Safety Power Shutoff: when PG&E turns off power during high fire-risk weather.
- Round-trip efficiency
- The share of energy you get back out of a battery after storing it, typically around 90%.
- SEER2
- An air conditioner's or heat pump's cooling efficiency over a typical summer. Higher is better.
- Solar Billing Plan
- PG&E's current billing plan for new solar customers, also called net billing or NEM 3.0. More
- Therm
- The unit natural gas is billed in, equal to 100,000 BTU of heat energy.
- Time-of-use (TOU)
- A rate plan where the price of electricity depends on the time of day. More
- True-up
- The once-a-year settlement for solar customers, when a year of charges and credits is added together.
- UEF
- Uniform Energy Factor: the efficiency rating for water heaters. Heat pump models are rated roughly 3 to 4. More
Missing a term? Ask Robert and it may show up here.