Sizing selects the aroTHERM plus rung nearest PSR ~0.8 (0.8 x design heat
loss) — the Appendix-N efficiency peak, reproducing the pump a real
installer fits — rather than the MCS PSR>=1.0 capacity target, which
oversizes. Validated against the relodged Elmhurst ASHP cert (delta 0
held at the 5 kW Vaillant); the two self-snapshot pins re-pin to their
correctly-sized larger pumps, and the orchestrator/harness thread the
calculator's design heat loss so production sizes to the dwelling. Manual
SapResult test stubs carry the new design_heat_loss_kw field.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
_ashp_option threads its sized design heat loss into ashp_cost_inputs so
the cost band and the pump's efficiency record share one figure — a leaky
dwelling's larger pump is priced on the matching band.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
_ashp_option now selects the aroTHERM plus PCDB record matching the
threaded design heat loss (floor-area proxy fallback), so the overlay's
efficiency anchor is sized to the dwelling instead of a fixed 5 kW unit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
design_heat_loss_kw = annual-average HLC x 24.2 K (SAP design temperature
difference) / 1000, the quantity Appendix N's PSR divides a heat pump's
rated output by — surfaced so the ASHP recommendation can size the pump.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
The sizing ladder (Vaillant aroTHERM plus 3.5-12 kW PCDB records) picks
the smallest rung whose rated output meets the design heat loss, so SAP
10.2 Appendix N reads the heat-pump efficiency near its PSR peak instead
of collapsing on an undersized fixed unit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
ADR-0048 records why a system-replacing heating override must emit a
complete companion set — category and control archetype-forced for
coherence, fuel and meter deferred where multiple values are valid, and
an unmapped companion logged rather than silently inherited. Adds the
Heating Companion Set glossary term to CONTEXT.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
A system-replacing override whose category or control is not yet mapped
now logs an error naming the archetype and code, so the incomplete
companion set (which otherwise silently inherits the replaced system's
value) is visible for review — log-and-continue, matching flag_fuel_mismatch.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Control 2601 (SAP Table 4e Group 6 room-heater, +0.3 C conservative
default) now overlaid for electric room heaters, matching the gas/oil/
solid siblings, so a replaced storage heater's manual charge control
2401 (+0.7 C) no longer survives and over-warms the modelled dwelling.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Category 10 (SAP Table 4a Room heaters) now overlaid for electric room
heaters (691-701), so a replaced storage heater's category 7 no longer
survives onto the effective cert and mis-bills via the Table 12a resolver.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
