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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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Latest Posts
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RE: The Changing Jet Stream Could Challenge UK Air Source Heat Pumps
... And that's being generous! I'll tell you a littl...
By SusannaSaunders , 6 hours ago
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RE: Adding data centre electricity costs to domestic energy bills?
never ceases to amaze me.. Keeping steel works going ...
By Batpred , 7 hours ago
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RE: Electricity price predictions
great session Reminds me why some politicians can be ha...
By Batpred , 7 hours ago
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RE: Boiler Upgrade Scheme funding reduced by circa £750 million in 2026 budget
Absolutely agree. The massive Hager CU my vaillant requ...
By Batpred , 7 hours ago
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RE: Why don't people choose heat pumps?
With a heatpump tariff, it should be cheaper to operate...
By Batpred , 7 hours ago
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RE: How much of your renewable and home setup would still work if the internet went down?
absolutely agree. even if many providers see that extra...
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RE: Octopussy cosy 6 experience
People who have a Cosy appear generally to be happy wit...
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I thought the cr*p came first and the biofuel came afte...
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RE: Aerotherm and weather compensation
@jamespa I replied yesterday with detailed readings whi...
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RE: Marvel Heating liquidation
@editor This is an important point. each winter, you...
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RE: Solar Power Output – Let’s Compare Generation Figures
Very nice. we’ve been super soggy here, but rather m...
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RE: DIY powerflushing tutorial
Interesting! I toyed with the idea too. But I installed...
By bobflux , 4 days ago
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RE: 15kw pump for 225m2 1990's house - over kill?
@seaviews Agree with the others on sequence: loft first...
By mk1234 , 4 days ago
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RE: Vaillant ecoTEC Plus - Flow Temp and Set Up
Heating been on for 4 weeks now, continuous. It's 6C o...
By trebor12345 , 5 days ago



