WattWorks by Forged Renewables LTD

Configuration

Welcome to the WattWorks Calculator ⚡

Use this tool to see how solar PV and battery systems can impact your energy bills.

Simply enter your electricity usage and tariff details, add your proposed solar or battery setup, and click "Calculate Economics."

You'll see your estimated savings, ROI, and payback period based on your inputs.

(Tariffs and results may vary depending on your energy provider and location.)

1. Baseline Usage & Current Tariff ▶

Annual Electricity Consumption (kWh/year)

Standing Charge (£/day)

Unit Rate (£/kWh)

Export Rate / SEG (£/kWh)

2. Solar PV ▶

Include Solar PV

3. Battery ▶

Include Battery Storage

Usable Capacity (kWh)

Round-Trip Efficiency

Max Charge Power (kW)

Allow battery to top up from cheap grid windows

Inverter Operating Mode ?

4. Installation Costs ▶

Proposed Installation Cost (£) *

Total cost including battery, inverter, installation, and VAT (if applicable).

Grants or Rebates (£)

Any grants, rebates, or incentives that reduce your out-of-pocket cost.

Cost includes VAT

5. Post-Installation Tariff & SEG ▶

Tariff Preset

Standing Charge (£/day)

SEG Export Rate (£/kWh)

Cheap Window Start (HH:MM)

Cheap Window End (HH:MM)

Cheap Rate (£/kWh)

Standard Rate (£/kWh)

6. Heating ▶

Include Heating Analysis

My annual electricity usage already includes heating

Check this if you already have a heat pump or all-electric heating and your baseline electricity consumption already includes heating loads.

Heating Type

Annual Heat Demand (kWh)

Find this on your EPC certificate or annual gas bill (kWh used for heating). If unsure, use the estimator below.

Estimate from house size:

Typical UK homes: 50-100 kWh/m² for good insulation, 100-150 kWh/m² average, 150-200+ kWh/m² poor

Gas Price (existing boiler) — £/kWh

Your current gas unit price from your bill. Used to compare existing boiler running cost against a heat pump or electric heating.

Boiler Efficiency (%)

COP (Coefficient of Performance)

Load shifting

Shiftable Percentage (%)

Heating Installation Cost (£)

Cost for any new heating system installation (can be added to CAPEX).

7. Optional: Home Value Impact ▶

Include an estimate of how solar, battery storage and a heat pump might affect your property's resale value. This section is optional and not required for payback / ROI calculations.

Include property value uplift in results

Results

Configure your system and click "Calculate Economics" to see results.

WattWorks

Configuration

Results

Payback Over Time

Results

Information