Energy Efficiency Calculator

Analyse your home's energy efficiency and discover key improvement areas. Get your energy rating and learn how to reduce costs whilst improving comfort.

Energy Efficiency Calculator

Analyse home energy efficiency and savings potential

Monthly energy usage

Cost per kilowatt-hour

Total living space size

Energy Rating Scale

Understanding the A-G energy efficiency rating system used across the UK and Europe

A
B
C
D
E
F
G
Most Efficient
Very Efficient
Efficient
Average
Below Average
Poor
Least Efficient

Key Improvement Areas

Focus areas that can significantly improve your home's energy efficiency

Insulation

Improve wall, loft, and floor insulation

Heating System

Upgrade to efficient boiler or heat pump

Windows

Install double or triple glazing

Smart Controls

Add programmable thermostats and zones

  1. 1

    Gather 12 Months of Energy Bills

    Collect electricity and heating fuel bills for past year. Add up total kWh, therms, litres, or cubic metres used. Calculate annual energy cost in pounds. This baseline is crucial for measuring improvement savings. Average UK household: £1,500-£2,500/year total energy.

  2. 2

    Get Home Energy Assessment

    Professional assessment (£300-£600) or DIY assessment identifies: air leaks, insulation gaps, draughts, inefficient appliances, heating system performance. Provides EPC rating (A-G scale). Many energy suppliers offer free assessments. Prioritises improvements by cost-effectiveness.

  3. 3

    Set Savings Target

    Choose realistic goal: 10-20% (low-cost upgrades - draught-proofing, loft insulation top-up, smart thermostat), 30-50% (major upgrades - heat pump, cavity wall insulation, new windows), 60-80% (deep retrofit + solar). Higher targets need larger investment but achieve better EPC rating.

  4. 4

    Plan Investment Budget

    Allocate funds by cost-effectiveness: High ROI (<3 years): Draught-proofing £200-£400, loft insulation £400-£1,000, LED lighting £100-£300, smart thermostat £200-£300. Medium ROI (3-8 years): Cavity wall insulation £1,000-£2,500, heat pump £8,000-£14,000 (after grant), double glazing £4,000-£8,000. Long ROI (8-15 years): Solar panels £5,000-£8,000, solid wall insulation £8,000-£15,000, battery storage £4,000-£8,000.

  5. 5

    Calculate Savings and Payback

    Calculator shows: annual energy reduction (kWh and %), pound savings per year, total investment cost, simple payback period, 20-year net savings. Factor in: ECO4/Great British Insulation Scheme grants (free/subsidised insulation for eligible households), Boiler Upgrade Scheme (£7,500 for heat pumps), 0% VAT on energy-saving materials, increased property value (better EPC = higher sale price), improved comfort, and reduced carbon emissions.

Pro Tip: Use Ctrl+Enter to calculate quickly, or Ctrl+R to reset the form.

Frequently Asked Questions

Rank by ROI: 1) Air sealing (£200-500, 10-20% savings, <2 year payback), 2) Loft insulation (£1,000-2,500, 15-25% savings, 3-7 years), 3) Programmable thermostat (£100-250, 10-15% savings, <1 year), 4) LED bulbs (£2-5 each, 75% lighting savings, <1 year), 5) Water heater blanket (£30, 5-10% water heating savings, <1 year).

Yes, but requires comprehensive approach: deep insulation upgrade (20-25%), heat pump installation (30-40%), LED lighting (5-8%), Energy Star appliances (5-10%), air sealing (10-15%), solar panels (offset remaining). Total investment: £20,000-40,000. Realistic timeline: 3-5 years of staged improvements. Start with highest-ROI projects first.

UK Government schemes: ECO4, Great British Insulation Scheme, Boiler Upgrade Scheme (£5,000-6,000 for heat pumps). Check eligibility for grants covering: heat pumps, insulation, windows/doors. Council and energy supplier schemes may offer additional support. Grants significantly reduce payback periods.

Staged approach is smarter financially and practically. Phase 1 (Year 1): Air sealing + loft insulation + programmable thermostat (£1,500-3,500). Phase 2 (Year 2-3): Windows or heat pump (£5,000-15,000). Phase 3 (Year 4-5): Solar panels (£15,000-30,000). Benefits: spread costs, learn from each upgrade, refinance based on savings, qualify for annual grants. Do envelope first, then systems.

Use this framework: 1) Calculate savings ÷ cost = ROI for each project, 2) Start with payback <5 years (air sealing, insulation, thermostat), 3) Address comfort issues (draughts, cold rooms) - high quality-of-life ROI, 4) Do envelope before equipment (insulation before new HVAC), 5) Stack incentives (government + council + energy supplier grants), 6) Consider lifespan - if boiler dying soon, upgrade to heat pump vs basic replacement.

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