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docs(pashub): Elmhurst input sheets for the Varsity Rise cluster

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The 12 Varsity Rise (Louth) homes are the only community-heated dwellings in
the LRHA WAVE 3 cohort and the only residual over-rate cluster (~+1 SAP). Two
candidate causes cannot be adjudicated from PasHub's `pre_sap` alone and need
accredited Elmhurst worksheets: (A) an electric-immersion DHW fuel-code
collision that bills immersion as community biomass (code 42), and (B) a
suspected community-DHW solar over-credit (the parser drops solar-collector
geometry, so the engine takes Table-29 defaults).

Add page-by-page Elmhurst RdSAP input sheets for one cert of each type
(461386632388 group A, 497671579889 group B) with a "what to read back" list
of the worksheet lines needed to diff term-by-term. Also correct the immersion
single → dual note on the 497655371974 build sheet (the cert lodges Dual).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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@ -113,7 +113,8 @@ Party-wall length: 0 (detached).
### Water heating
- **Electric immersion** cylinder (SAP WHC **903**), fuel electricity
- Immersion: **single** · on the Economy-7 (off-peak) meter
- Immersion: **dual** · on the Economy-7 (off-peak) meter
(the cert lodges "Immersion: Dual" and the engine models dual, `immersion_heating_type=1` — a dual immersion bills part of DHW at the off-peak rate, so build it as **Dual** in Elmhurst or the comparison will not be faithful)
- Cylinder size: **Small band ≈110 L** (RdSAP Table 28 code 2)
- Insulation: **factory-fitted foam, 50 mm** · Cylinder thermostat: **No**
- Electric shower ×1 · Bath ×1 · Mixer shower ×0

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# Elmhurst RdSAP input sheet — PasHub cert 461386632388 (11 Varsity Rise, Louth)
Purpose: reproduce PasHub LRHA WAVE 3 cert **461386632388** (11 Varsity Rise,
Louth, LN11 8UY) in the Elmhurst RdSAP 10 entry tool, download its **Input
Summary + SAP Worksheets**, and read back the **§12 fuel-cost / community-hot-
water / Appendix-H solar-HW lines**. This adjudicates **Group A** of the Varsity
Rise community-heating over-rating: a suspected **mapper fuel-code collision that
bills the electric-immersion DHW as community biomass**.
This is a PasHub *site-notes* cert (surveyor's Record of Inspection), **not** a
gov-API cert, so the `epc-to-elmhurst-rdsap-inputs` skill (UPRN / cert-number /
`epc.json` only) does not apply — every value below is derived directly from the
parsed dwelling (`parse_site_notes_pdf(...)`) and the raw survey PDF text.
## What this cert is (and why it matters)
A 2-storey timber-frame semi (age band **K**, 2007–2011) on the Varsity Rise
**community-heating network — biomass boilers only, no CHP**. Space heating is
100% community biomass. **Hot water is a separate electric-immersion cylinder
(180 L)** — it is *not* taken from the community main. There is **solar water
heating** (water-heating only). This is the immersion-DHW member of the pair;
cert 497671579889 (9 Varsity Rise) is the from-community-main DHW member.
**The Group A hypothesis, confirmed in our engine's inputs:** the electric
immersion (RdSAP water-heating code **903**, fuel should be grid electricity) is
being priced/carbon-accounted as **hot-water fuel code 42** — a community/biomass-
family code — with **CO₂ 0.015 kg/kWh, primary factor 0.063, cost 4.24 p/kWh**.
Grid electricity would be ≈0.136 kg/kWh, PE ≈1.5, ≈30 p/kWh. So the immersion DHW
is being credited as near-zero-carbon biomass heat → this over-credits DHW and
over-rates SAP (matches PasHub `pre_sap` **D61** and the cohort's +~1 over-rating).
Elmhurst's accredited §12 / community-HW lines are needed to prove the correct
DHW fuel and settle this.
## Our engine's output (to compare against Elmhurst)
| Quantity | Our engine |
|---|---|
| SAP score (continuous / band) | **62.50** (D) |
| Space-heating demand | 5 923 kWh/yr |
| Main heating fuel (community biomass, code 43) | 8 884 kWh/yr |
| Hot-water demand | 1 988 kWh/yr |
| **Hot-water fuel code applied** | **42** (community/biomass family — the suspected collision) |
| HW cost / CO₂ / PE factors | **4.24 p/kWh · 0.015 kg/kWh · 0.063** |
| CO₂ | 643 kg/yr |
| Total fuel cost | £835/yr |
PasHub `pre_sap` for this dwelling: **D61**. If Elmhurst prices the immersion DHW
at an *electricity* tariff (Table 12 code 29/30, not the community/biomass rate),
that is the confirmation the mapper is mis-billing DHW — and the fix would pull
our SAP down toward PasHub.
---
## Page-by-page inputs
### Property / general
- Address: **11 Varsity Rise, Louth, Lincolnshire, LN11 8UY**
- Property type: **House** · Built form: **Semi-Detached**
- Tenure: **Rented (social)** · Transaction type: **Rental**
- Inspection date: **2025-08-05** · Measurements: **Internal** · Terrain: **Suburban**
- Age band: **K** (England & Wales **2007–2011**)
- Storeys: **2** · Habitable rooms: **3** · Heated habitable rooms: 3 (none unheated)
- Extensions: **1** · Rooms in roof: **No**
- Total floor area: **85.44 m²** (ground 39.76 + first 39.76 + extension 5.92)
- Country: England
- Mains gas: **No** (all community-heat + electric dwelling)
### Dimensions
Give Elmhurst the **RAW surveyed storey height** — Elmhurst adds the RdSAP +0.25 m
upper-storey (joist-void) allowance itself. (Our mapper already applied +0.25 to
the first floor internally: it stores 3.79, the survey recorded 3.54.)
| Level | Storey height (m, raw survey) | Floor area (m²) | Heat-loss perimeter (m) | Party-wall length (m) |
|---|---|---|---|---|
| Ground (main) | 2.32 | 39.76 | 20.06 | 3.47 |
| First (main) | 3.54 | 39.76 | 22.57 | 3.47 |
| Extension 1 (ground) | 3.71 | 5.92 | 7.23 | 0 |
### Walls
- Construction: **Timber frame** (survey: "window frames set back from wall face")
- Insulation: **As built** · thermal conductivity **Unknown** · U-value **Not known**
- Thickness: **270 mm** (measured) — both main + extension
- Same construction on the extension.
- Party wall: survey "**Unable to determine**" → parsed as code 0. Enter Elmhurst
party-wall as **Timber-frame party wall / Unable to determine** (see Fields-to-clear note).
### Roof
- Main + extension: **Pitched roof, sloping ceiling** · insulation **at sloping
ceiling** · thickness **As built** · U-value **Not known** · no rooms in roof.
### Floor
- **Solid** ground floor (main + extension) · insulation **As built** · U **Not known**.
### Windows / doors
- **12 windows**, all **double glazing installed 2002–2021**, frame **Wooden or
PVC**, all **draught-proofed**, no shutters. Dated by property build date.
- Per-window survey geometry (H × W m, orientation):
| # | Location | H (m) | W (m) | Orientation |
|---|---|---|---|---|
| 1 | Extension 1 | 0.94 | 0.41 | SW |
| 2 | Main | 0.55 | 1.55 | NW |
| 3 | Main | 2.05 | 1.78 | SE |
| 4 | Main | 1.28 | 0.43 | SE |
| 5 | Main | 2.05 | 1.78 | SE |
| 6 | Main | 1.24 | 0.43 | SW |
| 7 | Main | 0.89 | 0.55 | NW |
| 8 | Main | 1.05 | 1.79 | SE |
| 9 | Main | 0.93 | 0.55 | SE |
| 10 | Main | 0.95 | 0.55 | NE |
| 11 | Main | 1.05 | 1.17 | SE |
| 12 | Main | 0.95 | 0.41 | NW |
(Our engine's total window heat loss = **27.11 W/K**; enter the geometry above so
Elmhurst derives its own glazed area rather than a band default.)
- Doors: **1** external, **draught-proofed**, **0** insulated.
- Draught-proofing: **100%**.
### Ventilation
- **MV with Heat Recovery (MVHR)** · **not** in the PCDF database → Elmhurst uses
the **RdSAP default MVHR** in-use efficiency. No air-pressure test.
- Draught lobby: **No**.
- Open/closed/boiler/other flues: **0/0/0/0** · Extract fans: **0** · Passive
vents: **0** · Flueless gas fires: **0**.
- Open chimneys: **0** · Blocked chimneys: **0**.
- Sheltered sides: **1** (mapper default for semi-detached — survey does not record).
### Lighting
- Fixed low-energy: **11 of 11 → 100%** (1 LED + 10 CFL, 0 incandescent).
### Electricity meter / tariff
- Meter type: **Single** (survey; no smart meter) → our engine `is_off_peak_meter =
False`. **Enter Single, not Economy-7.** (The immersion is *not* on an off-peak
meter here, so the usual off-peak fuel-cost gotcha does **not** apply.)
- Export-capable: **No** · PV / wind / battery / hydro: **none**.
### Main heating system 1 (community)
- **Community heating system** (RdSAP main-heating code **301**, main fuel type **43**)
- Community heat source / fuel: **Heat from boilers — biomass** · "**Community
heating — boilers only**" (no CHP).
- Community distribution type: **Unknown** → distribution-loss factor is a default
(read back Elmhurst's applied value).
- CHP fraction: **none recorded** (boilers only).
- Controls: "**Charging system linked to use of community heating, room thermostat
and TRVs**" (parsed control **2314**).
- Fraction: **100%**.
### Secondary heating
- **None** (survey: "No Secondary Heating").
### Water heating ← Group A load-bearing page
- **Electric immersion** cylinder (RdSAP water-heating code **903**), fuel
**electricity** (survey water-heating fuel).
- Immersion: **Single** (parsed `immersion_heating_type = 2`).
- Cylinder: **exact volume 180 L** · insulation **factory-fitted foam, 50 mm** ·
measured heat loss **Not known** · **cylinder thermostat: Yes**.
- **Solar water heating: Yes** (service provision **water-heating only**):
- Survey: **pitch 30°**, **orientation South-East**, **overshading None or very
little**, **non-electric showers only**, **solar-panel details NOT known**,
circulating pump **electrically powered**.
- ⚠️ The PasHub parser **dropped the collector geometry** —
`solar_hw_collector_orientation`, `solar_hw_collector_pitch_deg` and
`solar_hw_overshading` all parse to **None**. Our engine therefore falls back
to **RdSAP Table 29 defaults**: aperture **3.0 m²**, η₀ **0.8**, **South / 30°**,
overshading **"Modest"**, combined-cylinder pre-heat = **⅓ of 180 L = 60 L**.
So enter the **surveyed** values in Elmhurst (**SE / 30° / overshading none-or-
very-little / details unknown**) and note the divergence from our defaults.
- Electric shower: **0** · Mixer shower: **1** · Bath: **1** · WWHRS: **None**.
---
## Fields to clear in Elmhurst (do NOT map)
| Elmhurst page · field | Set to | Why absent |
|---|---|---|
| Property Description · Room-in-Roof age band | (blank) | no rooms in roof |
| Dimensions · Room(s)-in-Roof area | (blank) | ditto — leave empty, not 0 |
| Dimensions · Extensions 2–4 | (blank) | one extension only |
| Ventilation · flues / fans / vents / chimneys | 0 | none recorded |
| Space Heating · Main Heating 2 | none | single (community) main system |
| Space Heating · Secondary heating | none | "No Secondary Heating" |
| Water Heating · WWHRS / FGHRS | none | WWHRS "None"; no FGHRS lodged |
| New Technologies · PV / Wind / Hydro / battery | none | none lodged |
| Conservatory | none | "No conservatory" |
| Meters · Economy-7 / dual-rate | **Single** | survey meter type Single (do not set off-peak) |
---
## What to read back (accredited Elmhurst worksheet lines)
To adjudicate the Group A residual, capture from the **SAP Worksheet** PDF:
1. **SAP score** (continuous + band) from the Input Summary — compare to our **62.50 (D)** and PasHub `pre_sap` **D61**.
2. **§12 / water-heating fuel-cost line for the immersion DHW** — the **p/kWh, CO₂
factor and primary-energy factor Elmhurst applies to the hot water**. This is
the load-bearing number: our engine applies a **community/biomass** set
(**4.24 p/kWh · 0.015 kg/kWh · 0.063 PE**, fuel code 42). If Elmhurst applies an
**electricity** tariff instead, the fuel-code collision is confirmed.
3. **Community-heating worksheet lines** (space-heating side): the community
**biomass** unit cost/CO₂/PE, the **distribution-loss factor** applied, and
confirmation of **no CHP** — so we can check the space-heating side is correct
even while the DHW side is not.
4. **Appendix-H / solar-water-heating lines (H1–H24, esp. (H24)/line 64m)** — the
annual **solar input kWh** deducted from the DHW demand, plus the **collector
aperture, η₀, orientation, pitch and overshading** Elmhurst used. Compare to our
Table-29 defaults (3.0 m², 0.8, S/30°, Modest) since the parser dropped the
surveyed SE/30°/low-overshading geometry.
5. (Nice to have) per-end-use kWh (space heating, water heating, solar contribution)
to pin alongside the score.
## Inputs I was unsure about / had to infer
- **Party wall** "Unable to determine" (survey) → parsed code 0; Elmhurst party-
wall category is a judgement call (timber-frame party wall, U≈0).
- **Solar collector geometry** — surveyed (SE/30°/low overshading, details unknown)
but **dropped by the PasHub parser**; our engine used Table-29 defaults. Enter the
surveyed values in Elmhurst; expect a small divergence from our number here.
- **Sheltered sides = 1** is a mapper default (not surveyed).
- **MVHR efficiency** — not in PCDF, so RdSAP default; not surveyed explicitly.
- **First-floor storey height 3.54 m raw** (mapper stores 3.79 after the +0.25
allowance) — transcribed as recorded even though it is taller than the ground
floor; worth a sanity check on the survey.

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# Elmhurst RdSAP input sheet — PasHub cert 497671579889 (9 Varsity Rise, Louth)
Purpose: reproduce PasHub LRHA WAVE 3 cert **497671579889** (9 Varsity Rise,
Louth, LN11 8UY) in the Elmhurst RdSAP 10 entry tool, download its **Input
Summary + SAP Worksheets**, and read back the **community-hot-water and
Appendix-H solar-water-heating lines**. This adjudicates **Group B** of the
Varsity Rise community-heating over-rating: **community DHW "from main heating 1"
with a suspected solar-water-heating over-credit** interacting with the
community-DHW Appendix-H path.
This is a PasHub *site-notes* cert (surveyor's Record of Inspection), **not** a
gov-API cert, so the `epc-to-elmhurst-rdsap-inputs` skill (UPRN / cert-number /
`epc.json` only) does not apply — every value below is derived directly from the
parsed dwelling (`parse_site_notes_pdf(...)`) and the raw survey PDF text.
## What this cert is (and why it matters)
A 2-storey timber-frame semi (age band **K**, 2007–2011) on the Varsity Rise
**community-heating network — biomass boilers only, no CHP** — the same network
and near-identical fabric as 11 Varsity Rise (cert 461386632388). Here both space
heating **and hot water** come from the community main: **Water Heating System =
"From main heating 1"** (RdSAP water-heating code **901**). There is also **solar
water heating** (water-heating only). This is the from-community-main DHW member
of the pair; cert 461386632388 (11 Varsity Rise) is the electric-immersion member.
**The Group B hypothesis:** because DHW is drawn from the community main *and* a
solar collector is present, the Appendix-H solar pre-heat credit is applied on top
of the community-heat DHW. With the collector geometry unknown, our engine defaults
to a **Table-29 3.0 m² collector** and deducts a solar input from DHW demand — a
possible over-credit that, combined with the near-zero-carbon community-biomass DHW
factors, would over-rate SAP (PasHub `pre_sap` **D58**). Elmhurst's accredited
community-HW + Appendix-H (H)-series lines are needed to size the solar credit and
the community DHW factors correctly.
## Our engine's output (to compare against Elmhurst)
| Quantity | Our engine |
|---|---|
| SAP score (continuous / band) | **59.42** (D) |
| Space-heating demand | (main, code 43) 8 845 kWh/yr |
| Hot-water demand | 3 353 kWh/yr |
| **Hot-water fuel code applied** | **43** (community biomass — DHW from main, as expected) |
| HW cost / CO₂ / PE factors | 4.24 p/kWh · 0.03625 kg/kWh · 1.296 |
| CO₂ | 738 kg/yr |
PasHub `pre_sap` for this dwelling: **D58**. Note the DHW here is correctly coded
**43 (community biomass)** — unlike the immersion cert 461386632388 which mis-codes
DHW to 42 — so Group B's residual is expected to sit in the **solar-HW credit
size**, not a fuel-code collision.
---
## Page-by-page inputs
### Property / general
- Address: **9 Varsity Rise, Louth, Lincolnshire, LN11 8UY**
- Property type: **House** · Built form: **Semi-Detached**
- Tenure: **Rented (social)** · Transaction type: **Grant-Scheme (ECO, RHI, etc.)**
- Inspection date: **2025-10-22** · Measurements: **Internal** · Terrain: **Suburban**
- Age band: **K** (England & Wales **2007–2011**)
- Storeys: **2** · Habitable rooms: **3** · Heated habitable rooms: 3 (none unheated)
- Extensions: **1** · Rooms in roof: **No**
- Total floor area: **84.28 m²** (ground 39.25 + first 39.25 + extension 5.78)
- Country: England
- Mains gas: **No**
### Dimensions
Give Elmhurst the **RAW surveyed storey height** — Elmhurst adds the RdSAP +0.25 m
upper-storey (joist-void) allowance itself. (Our mapper already applied +0.25 to
the first floor internally: it stores 4.00, the survey recorded 3.75.)
| Level | Storey height (m, raw survey) | Floor area (m²) | Heat-loss perimeter (m) | Party-wall length (m) |
|---|---|---|---|---|
| Ground (main) | 2.33 | 39.25 | 19.72 | 3.64 |
| First (main) | 3.75 | 39.25 | 22.22 | 3.64 |
| Extension 1 (ground) | 3.82 | 5.78 | 7.12 | 0 |
### Walls
- Construction: **Timber frame** (survey: "window frames set back from wall face")
- Insulation: **As built** · thermal conductivity **Unknown** · U-value **Not known**
- Thickness: **300 mm** (measured) — both main + extension
- Party wall: survey "**Unable to determine**" → parsed as code 0. Enter Elmhurst
party-wall as **Timber-frame party wall / Unable to determine**.
### Roof
- Main + extension: **Pitched roof, sloping ceiling** · insulation **at sloping
ceiling** · thickness **As built** · U-value **Not known** · no rooms in roof.
### Floor
- **Solid** ground floor (main + extension) · insulation **As built** · U **Not known**.
### Windows / doors
- **14 windows**, all **double glazing installed 2002–2021**, frame **Wooden or
PVC**, all **draught-proofed**, no shutters. Dated by property build date.
- Per-window survey geometry (H × W m, orientation):
| # | Location | H (m) | W (m) | Orientation |
|---|---|---|---|---|
| 1 | Main | 2.05 | 1.80 | S |
| 2 | Main | 1.35 | 0.40 | E |
| 3 | Main | 0.50 | 1.20 | N |
| 4 | Main | 0.90 | 0.50 | N |
| 5 | Main | 0.90 | 0.50 | S |
| 6 | Main | 2.05 | 2.35 | S |
| 7 | Main | 0.70 | 0.41 | N |
| 8 | Extension 1 | 1.24 | 0.30 | N |
| 9 | Main | 0.75 | 0.62 | S |
| 10 | Main | 1.04 | 1.16 | S |
| 11 | Main | 0.70 | 0.40 | N |
| 12 | Main | 0.96 | 0.59 | S |
| 13 | Main | 1.05 | 1.15 | S |
| 14 | Main | 0.70 | 0.75 | N |
(Our engine's total window heat loss = **28.63 W/K**; enter the geometry above so
Elmhurst derives its own glazed area rather than a band default.)
- Doors: **1** external, **draught-proofed**, **0** insulated.
- Draught-proofing: **100%**.
### Ventilation
- **MV with Heat Recovery (MVHR)** · **not** in the PCDF database → Elmhurst uses
the **RdSAP default MVHR** in-use efficiency. No air-pressure test.
- Draught lobby: **No**.
- Open/closed/boiler/other flues: **0/0/0/0** · Extract fans: **0** · Passive
vents: **0** · Flueless gas fires: **0**.
- Open chimneys: **0** · Blocked chimneys: **0**.
- Sheltered sides: **1** (mapper default for semi-detached — survey does not record).
### Lighting
- Fixed low-energy: **12 of 12 → 100%** (0 LED + 12 CFL, 0 incandescent).
### Electricity meter / tariff
- Meter type: **Single** (survey; smart meter present) → our engine
`is_off_peak_meter = False`. **Enter Single, not Economy-7.**
- Export-capable: **Yes** · PV / wind / battery / hydro: **none**.
### Main heating system 1 (community)
- **Community heating system** (RdSAP main-heating code **301**, main fuel type **43**)
- Community heat source / fuel: **Heat from boilers — biomass** · "**Community
heating — boilers only**" (no CHP).
- Community distribution type: **Unknown** → distribution-loss factor is a default
(read back Elmhurst's applied value).
- CHP fraction: **none recorded** (boilers only).
- Controls: "**Charging system linked to use of community heating, room thermostat
and TRVs**" (parsed control **2314**).
- Fraction: **100%**.
### Secondary heating
- **None** (survey: "No Secondary Heating").
### Water heating ← Group B load-bearing page
- **From main heating 1** (community) — RdSAP water-heating code **901** (DHW served
by the community biomass main, fuel code 43).
- Cylinder: **Medium band (131–170 L)** · insulation **factory-fitted foam, 50 mm** ·
measured heat loss **Not known** · **cylinder thermostat: Yes**.
(Exact volume not surveyed → RdSAP medium-band volume; our engine `cylinder_size = 3`.)
- **Solar water heating: Yes** (service provision **water-heating only**):
- Survey: **pitch 30°**, **orientation South**, **overshading None or very little**,
**non-electric showers only**, **solar-panel details NOT known**, circulating
pump **electrically powered**.
- ⚠️ The PasHub parser **dropped the collector geometry** —
`solar_hw_collector_orientation`, `solar_hw_collector_pitch_deg` and
`solar_hw_overshading` all parse to **None**. Our engine therefore falls back to
**RdSAP Table 29 defaults**: aperture **3.0 m²**, η₀ **0.8**, **South / 30°**,
overshading **"Modest"**, combined-cylinder pre-heat = **⅓ of the cylinder
volume**. The surveyed **South / 30° / low overshading** is close to the default,
so the **aperture (3.0 m²) and η₀ (0.8) defaults are the load-bearing
assumptions** for the suspected over-credit — enter the surveyed values and read
back Elmhurst's aperture.
- Electric shower: **0** · Mixer shower: **1** · Bath: **1** · WWHRS: **None**.
---
## Fields to clear in Elmhurst (do NOT map)
| Elmhurst page · field | Set to | Why absent |
|---|---|---|
| Property Description · Room-in-Roof age band | (blank) | no rooms in roof |
| Dimensions · Room(s)-in-Roof area | (blank) | ditto — leave empty, not 0 |
| Dimensions · Extensions 2–4 | (blank) | one extension only |
| Ventilation · flues / fans / vents / chimneys | 0 | none recorded |
| Space Heating · Main Heating 2 | none | single (community) main system |
| Space Heating · Secondary heating | none | "No Secondary Heating" |
| Water Heating · immersion | none | DHW is **from main**, not immersion |
| Water Heating · WWHRS / FGHRS | none | WWHRS "None"; no FGHRS lodged |
| New Technologies · PV / Wind / Hydro / battery | none | none lodged |
| Conservatory | none | "No conservatory" |
| Meters · Economy-7 / dual-rate | **Single** | survey meter type Single |
---
## What to read back (accredited Elmhurst worksheet lines)
To adjudicate the Group B residual, capture from the **SAP Worksheet** PDF:
1. **SAP score** (continuous + band) from the Input Summary — compare to our **59.42
(D)** and PasHub `pre_sap` **D58**.
2. **Community hot-water worksheet lines** — the community **biomass** unit cost/CO₂/PE
applied to the DHW (our engine: 4.24 p/kWh · 0.03625 kg/kWh · 1.296 PE, code 43),
plus the **distribution-loss factor**. Confirm the DHW is priced as community heat
(code 43), i.e. that Group B does *not* share Group A's fuel-code collision.
3. **Appendix-H / solar-water-heating lines (H1–H24, esp. (H24)/line 64m)** — the
**annual solar input kWh** deducted from DHW demand and the **collector aperture,
η₀, orientation, pitch, overshading** Elmhurst used. This is the load-bearing
number for Group B: compare Elmhurst's aperture/η₀ to our **Table-29 defaults
(3.0 m², 0.8, S/30°, Modest)** since the parser dropped the surveyed geometry. An
Elmhurst solar input materially below ours confirms the over-credit.
4. **DHW demand + cylinder-loss lines** — cylinder volume band, insulation (foam
50 mm), thermostat — to check the pre-solar DHW demand (our engine: 3 353 kWh/yr)
the solar credit is applied against.
5. (Nice to have) per-end-use kWh (space heating, water heating, solar contribution)
to pin alongside the score.
## Inputs I was unsure about / had to infer
- **Solar collector geometry** — surveyed (South / 30° / low overshading, details
unknown) but **dropped by the PasHub parser**; our engine used Table-29 defaults
(**aperture 3.0 m², η₀ 0.8**). This is the primary Group-B unknown — enter the
surveyed values and read back Elmhurst's aperture/solar-input.
- **Cylinder volume** — only a **Medium (131–170 L)** band surveyed (no exact
volume); the ⅓ combined-cylinder solar pre-heat is taken off the band volume.
- **Party wall** "Unable to determine" (survey) → parsed code 0; Elmhurst category is
a judgement call (timber-frame party wall, U≈0).
- **Sheltered sides = 1** is a mapper default (not surveyed).
- **MVHR efficiency** — not in PCDF, so RdSAP default; not surveyed explicitly.
- **First-floor storey height 3.75 m raw** (mapper stores 4.00 after the +0.25
allowance) — taller than the ground floor; worth a sanity check on the survey.