greenhomesums
UK green-home calculators
Honest payback, running-cost and grant calculators for UK homeowners thinking about solar, heat pumps and EVs.
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Are solar panels worth it in the UK? Calculator + honest verdict
For most UK homes solar panels pay back in 7-11 years and save £15,000+ over 25 years. Enter your postcode for a personalised estimate. Powered by PVGIS satellite data.
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Solar Panel Payback Calculator UK — By Postcode
Solar panel payback calculator by UK postcode. Enter your postcode to see payback period, 25-year savings and annual generation for your region. Powered by PVGIS.
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Air source heat pump cost UK — running cost calculator + is it worth it?
Air source heat pump cost UK: £8,000–£14,000 installed, £7,500 BUS grant available. Calculate running cost vs gas boiler and 15-year total cost of ownership. Updated for 2026.
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Boiler Upgrade Scheme Grant Calculator UK
Check if you qualify for the UK Boiler Upgrade Scheme £7,500 grant for a heat pump — or £5,000 for a biomass boiler — and see your net install cost. Updated for 2026 rules.
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EV Home Charging Cost Calculator UK
Work out the real cost of charging your electric car at home vs public chargers, across UK time-of-use tariffs (Octopus Go, Intelligent Octopus, OVO Drive Anytime, E.ON Next Drive), and compare with petrol at today's prices.
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MEES Landlord Compliance Calculator UK
UK landlords: check whether your rental property meets the Minimum Energy Efficiency Standards (EPC C by 2028 / 2030), see the cheapest measure stack to close the gap, and model grants and penalty exposure.
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Octopus Agile Savings Calculator UK
Estimate how much you'd save — or lose — switching to Octopus Agile from a flat tariff, by DNO region. Models load shifting, EV charging and heat pump usage against a typical Agile hourly rate curve.
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Ofgem Price Cap Impact Calculator UK
See what the new Ofgem default-tariff price cap means for your annual and monthly energy bill. Updated every quarter — compare the current cap against the one it replaced for your electricity and gas use.
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EPC Band Upgrade Cost Calculator UK
Homeowner calculator: work out what it would cost to lift your property's EPC from its current band to C, B or A — with the cheapest measure stack, grant offsets, resale-value uplift and green-mortgage savings.
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Solar battery storage UK — cost, savings & payback calculator
Solar battery storage UK: typical cost £3,000–£6,000 added to solar. Calculate combined savings from solar panels, home battery and EV charging. 15-year net benefit with live Ofgem rates.
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Holiday-Let EPC Upgrade Calculator UK
Holiday-let operators: cost of upgrading your FHL's EPC to a target band, with grants, occupancy-weighted running-cost saving, comfort-premium revenue uplift, and FHL capital allowance notes.
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Solar Export Tariff Comparator UK
Compare UK Smart Export Guarantee (SEG) tariffs side-by-side. Enter your annual solar export and see exactly what each supplier — Octopus, E.ON, British Gas, EDF, OVO, Good Energy and more — will pay you per year.
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EV vs Petrol Running Cost Calculator UK
Compare the annual running cost of an electric car against an equivalent petrol car. UK figures with home vs public charging split, Octopus Go tariff presets, and post-2025 VED road tax.
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Heat Loss Calculator UK — Heat Pump Sizing
Estimate your home's heat loss in kilowatts — the single most important number for sizing an air source heat pump. UK fabric U-values, floor area, glazing and infiltration. Use before getting quotes.
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Loft and cavity wall insulation cost UK 2026 — savings calculator
Loft insulation costs £300–£600, cavity wall £400–£1,000. Both pay back in 1–6 years. Calculate your savings, payback and ECO4 grant eligibility for any UK home.
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Home battery storage UK without solar — cost, payback & is it worth it?
Home battery storage UK without solar: costs £2,800–£5,500, pays back in 7–10 years on Octopus Flux. Personalised payback calculator. If you have solar, see the solar battery storage calculator.
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Green Mortgage Savings Calculator UK
Lifetime saving from a UK green mortgage rate discount, given an EPC band uplift. Halifax, Nationwide, Barclays, NatWest, Santander products covered.
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Octopus Cosy vs Flux Tariff Comparator UK
Side-by-side comparison of Octopus Cosy (heat-pump-tuned), Flux (battery-tuned) and the standard variable. Annual £, peak-window share, export income.