From 7b50e5b7f5c50732fe42a19fb63caaa2911a6cb5 Mon Sep 17 00:00:00 2001 From: Khalim Conn-Kowlessar Date: Tue, 28 Jul 2026 09:23:11 +0000 Subject: [PATCH] docs(pashub): Elmhurst input sheets for the Varsity Rise cluster MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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) --- ...DOVER_1684_ELMHURST_INPUTS_497655371974.md | 3 +- ...ER_VARSITY_ELMHURST_INPUTS_461386632388.md | 217 +++++++++++++++++ ...ER_VARSITY_ELMHURST_INPUTS_497671579889.md | 221 ++++++++++++++++++ 3 files changed, 440 insertions(+), 1 deletion(-) create mode 100644 docs/HANDOVER_VARSITY_ELMHURST_INPUTS_461386632388.md create mode 100644 docs/HANDOVER_VARSITY_ELMHURST_INPUTS_497671579889.md diff --git a/docs/HANDOVER_1684_ELMHURST_INPUTS_497655371974.md b/docs/HANDOVER_1684_ELMHURST_INPUTS_497655371974.md index e8c2c165d..34ee4852a 100644 --- a/docs/HANDOVER_1684_ELMHURST_INPUTS_497655371974.md +++ b/docs/HANDOVER_1684_ELMHURST_INPUTS_497655371974.md @@ -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 diff --git a/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_461386632388.md b/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_461386632388.md new file mode 100644 index 000000000..aa519e7aa --- /dev/null +++ b/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_461386632388.md @@ -0,0 +1,217 @@ +# 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. diff --git a/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_497671579889.md b/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_497671579889.md new file mode 100644 index 000000000..2f95a10d7 --- /dev/null +++ b/docs/HANDOVER_VARSITY_ELMHURST_INPUTS_497671579889.md @@ -0,0 +1,221 @@ +# 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.