Methodology

How Home Energy Scout estimates running costs, savings, sizing and comparisons

Home Energy Scout uses practical UK household estimates. Pages are built to be useful and transparent: good enough to guide a decision, not dressed up as a survey, quotation or installer design document.

UK-focused assumptionsLast reviewed: 16 April 2026Estimates, not guarantees

Core methods Where estimates are strongest Where judgement matters Methodology FAQ

Main calculation methods in use

Most live pages fall into four patterns. The point is not to force every question into one formula, but to use the simplest honest method for the job.

Running cost tools

Used for appliances, heaters and dehumidifiers.

Base formula: watts ÷ 1000 × hours used × tariff.
Common additions: standby power, duty cycle, or usage-mode interpretation.
Best use: setting a believable cost baseline before comparing options.

Savings and payback tools

Used for measures such as loft insulation and hot-water improvements.

Base logic: annual baseline spend × estimated saving rate.
Payback: upfront cost ÷ annual saving.
Best use: deciding whether the financial case is strong, weak, or secondary to comfort.

Room-sizing tools

Used where the room itself changes the answer.

Base logic: room volume × adjusted watts-per-cubic-metre factor.
Key adjustments: insulation, exposure and use pattern.
Best use: checking whether a heater or radiator choice is mis-sized before comparing models.

Comparison tools

Used when the verdict depends on behaviour, room fit and use pattern as much as wattage.

Base logic: compare typical wattages, room fit and runtime behaviour.
Key principle: direct electric heat costs the same per kWh, so fit and runtime matter more than marketing claims.
Best use: deciding what is likely to work better in practice, not just what looks cheapest on paper.

Where the estimates are strongest

Some questions respond well to simple household maths. Others are influenced by fabric condition, comfort expectations or installation quality.

Question type	Why the estimate is useful	What can still move the answer
Short appliance cycles	Wattage, time and tariff are usually enough for a good household estimate.	Real cycle length, eco mode, and standby behaviour.
Electric room heating	The cost per kWh is simple and clear.	Duty cycle, room fit, insulation and how often full output is needed.
Low-cost savings upgrades	Simple payback can be a fair screening tool.	How much waste was really there to begin with.
High-cost fabric upgrades	Directionally useful, but broader-brush.	Home condition, installation quality, access and comfort priorities.

Where judgement is deliberate

Some pages would be less trustworthy if they pretended to be exact.

Comparison pages often judge unlike options where speed, comfort, drying performance or room suitability matter as much as electricity use.
Savings pages sometimes prioritise directional honesty over false precision, especially for glazing and comfort-led upgrades.
Replacement pages are intentionally conservative because a working appliance with light annual use may not financially justify replacement yet.

What the site is trying to do

Give an ordinary UK household enough structure to answer a practical energy question quickly, with the assumptions close to the answer and the next step clearly signposted.

Methodology FAQ

Short answers to the trust questions most readers actually have.

Are the savings figures exact?

No. They are practical estimates designed to help with household decisions. Pages are deliberately cautious where real-world variation is large.

Why do some pages focus on comfort as well as payback?

Because some upgrades are chosen for warmth, condensation control, draught reduction or noise, not just for the fastest bill saving.

Why are electric-heating comparisons not just based on heater wattage?

Because direct electric heaters cost the same per kWh. The real differences are room fit, duty cycle, comfort and how the heater is used.