Oil-to-heat-pump conversion in Alderley Edge
12kW Daikin Altherma 3 replacing a tired 1990s oil boiler. Worst-case winter sized properly, BUS grant paperwork ready.
The Whittakers' 1970s detached house in Alderley Edge was running on an oil boiler approaching its third decade. Service costs were creeping, fuel deliveries were becoming a logistical pain, and the BUS grant made the maths work. They asked us to quote a heat-pump conversion alongside two other firms.
The full EN 12831 heat-loss calculation came in at 11.4kW for the worst-case winter day — well-insulated loft, decent cavity fill, but single-glazed Crittall windows on the north elevation pulling heat. We specified the Daikin Altherma 3 H HT 12kW unit, with a 250-litre integrated cylinder.
The other two quotes had specified 16kW units — comfortably oversized. An oversized heat pump short-cycles in mild weather, runs less efficiently, and costs more to buy. We talked the Whittakers through the heat-loss spreadsheet line by line so they could see why 12kW was the right answer.
Five-day install: oil tank decommissioned and removed, hot-water cylinder swapped, two of the radiators upgraded to handle the lower flow temperature, condenser sited behind the garage on a ground frame. The MCS-format paperwork went off with the BUS grant application the following week.
What went in.
The bill of materials, in mono. We publish this on every install — it's the same document the customer gets in their commissioning pack.
- Outdoor unit
- Daikin Altherma 3 H HT EPRA12DV3 · 12kW
- Cylinder
- Daikin EHSXB08P50D · 250L integrated
- SCOP @ 35°C
- 5.05
- SCOP @ 55°C
- 3.45
- Refrigerant
- R32, 4.2kg factory charge
- Radiators upgraded
- 2 × kitchen, 1 × landing
Replaced our oil boiler with a heat pump. Two other quotes were 16kW; David specified 12kW and walked me through the heat-loss spreadsheet line by line. The 12kW unit handles the worst weather we've had this winter without breaking a sweat, and the running costs are roughly half the oil bill. BUS grant paperwork was filed cleanly. No drama, just careful work.
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