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Calculators

Choose a hot-water calculator

Each calculator can be opened directly. The suggested order helps when household demand is not yet known, but no step is compulsory.

Optional order

Start with demand when unsure

  1. 1. Household Usage
  2. 2. Hot Water Cost
  3. 3. Heat Pump Payback

Electric vs Gas is an optional comparison, not a required fourth step. Every calculator supports direct entry.

Estimate Your Hot Water Use

Open Household Usage
What it helps answer
Estimate how much hot water the whole household may use each day.
Information to have ready
Household size, shower and bath use, tap use, and whether connected appliances draw hot water.
Result
Whole-household litres per day with activity contributions and visible assumptions.
Continuing with existing details
A valid submitted demand can continue to Hot Water Cost. The values remain available for review before that calculation is submitted.

Calculate Your Hot Water Costs

Open Hot Water Cost
What it helps answer
Estimate what a selected hot-water system may cost to run.
Information to have ready
A supported postcode or confirmed region, household demand, system type and electricity or gas tariff information.
Result
Annual and monthly running-cost estimates with system comparisons and disclosed inputs.
Continuing with existing details
Valid submitted details can arrive from Household Usage or Electric vs Gas. A submitted result can continue to Heat Pump Payback with accepted values carried across for review.

Heat Pump Savings & Payback

Open Heat Pump Payback
What it helps answer
Estimate an annual running-cost difference and indicative heat-pump payback.
Information to have ready
Current annual cost or system details, household demand, relevant tariffs and an upfront planning amount.
Result
An annual difference, indicative payback and fixed 5, 10, 15 and 20-year positions.
Continuing with existing details
Valid submitted information can arrive from Hot Water Cost. Carried values can be reviewed and changed before calculation.
Optional

Compare Electric vs Gas

Open Electric vs Gas
What it helps answer
Optionally compare two system types using the same household demand.
Information to have ready
A supported postcode or confirmed region, household demand, system choices and relevant tariffs.
Result
A variable running-cost comparison with the selected assumptions and exclusions.
Continuing with existing details
A valid submitted comparison can continue to Hot Water Cost. This calculator can also be opened directly.