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Last seen: May 10, 2026
About Me
Solar since 2011 4kW peak output; 19kWh Growatt Battery; BMWi3 EV and access to Octopus Intelligent Go 7p/kWh off-peak; 1905 detached house which has been thoroughly insulated to EPC B. Blower test showed 0.49 ACH. Heat Loss calculated 7.1kW.
Sept 2025 installed a new Vaillant aroTHERM 7kW heat pump, 300L Vaillant Unistor tank, 26m2 underfloor heating downstairs and upgraded radiators to cope with design calculated to meet 8kW heat loss. Combined heating and water SCOPs ranging between 3.5 and 5 between November and January.
Also added Daikin aircon in 30m2 Granny flat for summer cooling and winter heating SCOP >4.
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Slowly built up 4kW peak PV, 19.5kWh battery system, BMW i3 got us Octopus Intelligent Go low price off-peak supply, thorough insulation to EPC B in detached 1905 home, underfloor heating 26m2 of total 160m2. Vaillant 7kW pump, Unistor 300L cylinder. All working well and saving £1,500 / year versus gas central heating.
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