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Home Energy Optimiser

Find the cheapest way to run
your home’s heating — right now

Most UK homes have a mix of heating equipment added over the years — a gas boiler here, an air-to-air heat pump there, maybe a Sunamp or a battery. This tool works out the optimal way to run your specific combination, identifies which tariff you should be on, and ranks every possible upgrade by payback period. The model is calibrated to your building using the De Podesta heat-loss method.

Identifies your best available tariff — often a free switch worth £200+/year
Calibrates heat loss to your home using annual energy data
Ranks every upgrade by real payback period for your setup
Update as you add equipment — the merit order recalculates
Your heating merit order — cheapest source first
Answer the questions below to build your merit order
Step 1 of 6 — electricity access
Do you have a smart meter?
This determines which tariffs are available to you. Smart meters unlock time-of-use tariffs that can halve electricity costs versus a standard variable rate.
Step 2 of 6 — tariff unlocks
Which of these do you have?
Each asset unlocks additional tariff options. An EV alone can unlock Octopus Intelligent — the best available UK overnight rate at around 7p/kWh.
Step 3 of 6 — space heating
How do you heat your home?
Select all that apply. Hybrid setups are fully supported — the tool builds a dispatch order for your combination, running the cheapest source first.
Step 4 of 6 — hot water
How is your hot water heated?
Hot water accounts for 20–30% of total home heat spend. The optimal strategy depends heavily on whether you have thermal storage and what type.
Step 5 of 6 — building calibration
Let’s calibrate your heat loss
Your annual energy data plus postcode gives us your building’s heat loss coefficient — the number that makes every cost estimate specific to your home rather than a national average.
Find these figures on your annual energy statement or supplier app. Gas and electricity unit rates appear on the first page of any bill.
Postcode
Annual gas use
kWh/yr
Annual electricity
kWh/yr
Electricity rate
p/kWh
Gas unit rate
p/kWh
Home type
Your results
Your home energy profile
Recommended actions — ranked by return on investment

How the model works

The heat-loss calibration uses the De Podesta method, developed by National Physical Laboratory physicist Michael de Podesta. Your annual gas consumption divided by local heating degree days (from Open-Meteo historical data for your postcode) gives your building’s effective UA value — the rate at which it loses heat per degree of temperature difference. This is the same physical parameter a heat loss survey measures, derived from your actual behaviour rather than theoretical U-values.

The dispatch merit order assigns a cost-per-kWh of useful heat to each of your heating assets at current energy prices, and sequences them cheapest-first. Upgrade payback periods use the delta between your current dispatch cost and the projected cost with the new asset.

De Podesta heat-loss method Open-Meteo HDD data Octopus Agile / Intelligent Carnot COP modelling Merit order dispatch