How EnergyGuide uses data, estimates and assumptions
Energy information should be useful, honest and easy to act on. Our figures are designed to help UK households understand costs, compare options and ask better questions before spending money.
They are not promises, guarantees or personalised quotes. A home is not a spreadsheet, so we explain the assumptions, uncertainty and limitations behind the numbers wherever they matter.
The three principles behind our data
We prefer practical ranges and clear assumptions over numbers that look precise but do not reflect real homes.
Clarity
We explain what a figure means, what it includes, what it excludes and when it should be treated as only a guide.
Realism
Energy savings are affected by real homes, real weather, real behaviour and installation quality, not just laboratory assumptions.
Usefulness
Our data should help you compare options, understand trade-offs and prepare better questions for installers or advisers.
Where our information comes from
EnergyGuide uses publicly available data, recognised industry sources and market evidence to shape estimates and guidance. We give more weight to sources that are current, transparent, UK-relevant and based on real-world evidence.
Official and public data
- UK government energy statistics
- Housing and building performance data
- Fuel price and tariff information
- Emissions factors for different energy sources
- Regulations, schemes and technical standards
Market and product evidence
- Product specifications and efficiency ratings
- Installation cost data
- Installer, manufacturer and retailer information
- Industry reports and professional guidance
- Academic research, field trials and monitored studies
How we estimate energy savings
Savings depend on the measure being considered. Solar panels, insulation, heat pumps, boilers and appliances all depend on different variables, so we use typical scenarios rather than one-size-fits-all promises.
| Area | Variables we may consider | Why it matters |
|---|---|---|
| Property | Type, size, age, layout, insulation, ventilation and existing efficiency levels. | The same upgrade can perform differently across different homes. |
| Energy use | Heating habits, hot water use, appliance use, working from home and household occupancy. | Real household behaviour changes savings and payback. |
| Prices | Gas, electricity, oil, LPG, export rates, standing charges and tariff assumptions. | Fuel prices can change quickly and make old savings estimates stale. |
| Product performance | Efficiency ratings, system size, output, degradation, maintenance and real-world adjustments. | Rated performance is not always the same as real-world performance. |
| Installation | Installer quality, system design, commissioning, controls and remedial work. | A poor installation can reduce savings, comfort and reliability. |
The goal is to give a sensible indication of likely costs or savings. It is not to predict the exact outcome for every home.
Why your results may be different
Two households can install the same measure and see different results. That is not a flaw in energy data; it is the reality of homes, behaviour and changing prices.
Building differences
Age, construction, layout, insulation, ventilation and existing heating systems all affect performance.
How you use energy
Thermostat settings, hot water use, working from home and occupancy can change the outcome.
Prices change
Gas, electricity, oil, LPG, export rates and standing charges can move after an estimate is published.
Savings are not everything
Some improvements increase comfort rather than reducing bills by the full technical saving.
How we handle installation costs
Installation costs are hard to estimate accurately because prices vary between homes, regions, installers and job complexity. Our cost estimates are for early-stage planning, not a substitute for quotes.
What can change the price?
- Property size and building type
- Access requirements
- Location and labour costs
- Material costs and product specification
- Scaffolding or specialist equipment
- Electrical, plumbing or structural work
- Remedial work before or after installation
How to use our cost figures
Treat our cost estimates as guide prices unless we clearly state otherwise. They may not include surveys, repairs, upgrades, redecoration, maintenance or replacement parts.
For major work, get several quotes and check that each one covers the same scope of work.
How often we review figures
Different assumptions age at different speeds. Some data moves slowly, while energy prices, grant schemes and installer costs can change much faster.
Reviewed more often
Energy prices, standing charges, grant schemes, installation costs, solar export rates and policy-sensitive topics.
Reviewed when evidence changes
Product costs, market availability, heat pump/solar/boiler trends, appliance efficiency and installer practices.
Reviewed periodically
Typical property characteristics, building fabric assumptions and long-term technical explanations.
What our figures should and should not be used for
Useful for
- Comparing different home energy improvements
- Understanding likely costs
- Estimating possible bill or carbon savings
- Preparing questions for installers
- Understanding what affects payback
- Avoiding unrealistic claims
Not suitable for
- Guaranteed savings
- Fixed installation prices
- Property-specific assessments
- Professional surveys
- Financial, legal or investment advice
- Guaranteed grant eligibility
Simple payback can be useful, but installation cost divided by annual saving does not usually account for future fuel prices, finance costs, maintenance, inflation, lifespan or behaviour change.
Independence, commercial links and corrections
EnergyGuide is built to help people understand their options, not push one solution for every home. Commercial relationships should not decide the assumptions or technical guidance used in our content.
No single answer for every home
Solar panels, heat pumps, boilers, insulation and batteries all have strengths and limitations depending on the property.
Commercial links should be clear
If we use advertising, affiliate links or commercial partnerships, they should be clearly disclosed.
Better data should improve the page
When better evidence becomes available or an error is found, we aim to update the guidance.
How to cite EnergyGuide figures responsibly
You may reference EnergyGuide figures, but please do not present estimates as exact savings, fixed costs or property-specific advice.
When using our figures, include:
- The relevant EnergyGuide.org.uk page
- The date you accessed the information
- The publication or review date shown on the page
- Any assumptions shown alongside the figure
- A note that the figure is an estimate, not a guaranteed result
We will not pretend energy decisions are simpler than they are
Energy choices can involve large upfront costs and long-term consequences. Our job is to make the trade-offs clearer: likely ranges, main variables, useful questions and the limits of any estimate.
We may not be able to tell you exactly what a measure will save in your home, but we can help you understand what affects the outcome.
