Let's clear up the big one first: QII is not a credit anymore. If your compliance strategy from the 2022 cycle started with “add QII to buy margin,” that lever is gone — the 2025 code baked Quality Insulation Installation into the standard design for new construction. Including it earns you nothing over baseline. Skipping it costs you a penalty. It is a floor now, not a bonus, and we still see spec sheets in 2026 listing it as the plan for closing a compliance gap.
So what still moves the number? Fewer things than before, which makes the survivors worth knowing well.
Compact hot water distribution
Cluster your wet rooms near the water heater and the model rewards you. The credit comes in two tiers. The basic tier is claimed from the design drawings — short plumbing runs, demonstrated geometrically, no field verification. The verified tier is worth more and requires an ECC rater to confirm the installed piping matches. On a compact single-story plan the basic tier is nearly free money; you just have to actually draw the water heater near the bathrooms instead of defaulting it to the far garage corner. This one gets decided at floor-plan time, not at compliance time.
Whole-house fans
In the Central Valley and other hot-dry zones, a whole-house fan remains one of the more reliable cooling credits — flush the house with cool night air, shorten the next day's compressor runtime. The model credits it in the climate zones where night-flushing physics actually works, which is also where the new 2025 cooling metric bites hardest. A few hundred dollars of hardware that helps on the exact metric that got harder: worth a look on most CZ8–13 designs. It needs attic venting to relieve into, so coordinate with the roof design.
The self-utilization credit: PV plus a real battery
PV alone mostly satisfies the PV requirement; it does not do much extra work in the efficiency math. The self-utilization credit is the exception, and it has a hard prerequisite: paired battery storage with at least 5 kWh of capacity. The battery lets the model assume solar generation gets shifted into the evening hours the grid cares about, and the design collects a modest EDR credit for it.
Two honest caveats. The credit is capped — a bigger battery does not scale it linearly — and a battery installed purely to harvest this credit rarely pencils on compliance value alone. If the client wants storage anyway for outage resilience or rate arbitrage, take the credit. Do not sell the battery on the credit.
What earns nothing: ground-source heat pumps
Counterintuitive but true: a ground-source (geothermal) heat pump gets no compliance credit over the standard air-source heat pump baseline. The 2025 standard design already assumes an efficient heat pump, and the ruleset does not model ground-source performance as a distinct, creditable improvement. A client who spends five figures on a ground loop expecting it to rescue a failing compliance run will be disappointed. It may be a fine comfort and operating-cost decision. It is not a compliance strategy.
One last practical note: credits interact, and the only arithmetic that counts is the software's. Before promising a client that a whole-house fan closes the gap, run the actual model with the actual geometry. Margins that look generous in a rule of thumb have a way of thinning out in CBECC.