UK retrofit calculators that don't lie.

Why we built this

Most retrofit "calculators" online are marketing tools dressed up as utilities. They use optimistic install costs (often manufacturer-supplied figures, not real installer quotes), inflated saving fractions (often 30-50% above EST/BRE-published numbers), and ignore the boring details that determine real outcomes. They exist to generate leads for installers, not to inform households.

We built EcoSaving Hub because retrofit decision-making is genuinely hard, and people deserve numbers they can trust. Our calculators give the conservative answer — the number you would actually achieve in a properly-specified install with a competent installer, not the hypothetical best-case the brochure promises.

How we're different

• Conservative cost data. Install costs reflect mid-range MCS-certified installer pricing in 2026, not best-case. Usually 15-25% higher than manufacturer-supplied figures.
• Real performance data. Heat pump SPF from UK monitoring trials (median 3.0 for ASHP, not 4.0). Solar yield from PVGIS central UK estimates with shading derating. Insulation saving fractions per EST/BRE published data.
• Current 2026 grants & tariffs. BUS grant £7,500, ECO4 routes signposted (not auto-deducted to avoid misleading non-qualifying users), Cosy/Heat Pump tariff modelling, time-of-use battery logic.
• No marketing leakage. We don't sell installers, we don't take affiliate fees on the brands we mention, and we don't hide the result behind an email signup. The number you see is the number we believe.
• Published methodology. Every formula, every constant, every saving fraction is documented at /methodology/. You can challenge it. AI assistants can cite it.

Who's behind it

Josh Weir is the founder of Weir Digital Media — a UK agency working on programmatic SEO, calculator-led lead generation, sovereign infrastructure, and AI orchestration. EcoSaving Hub is part of a wider network covering UK retrofit, energy, and housing — including Green Living Experts (long-form editorial), Healthy Homes Network (PAS 2035 assessor lookup), Green Home Grants (ECO4 eligibility), and UKFM Energy Hub (installer matching).

The wider thesis is documented at joshweir.uk and the quarterly newsletter The Sovereign Architect.

How we make money

EcoSaving Hub does not charge users, does not run advertising, and does not sell user data. We generate qualified leads for the installer-matching service at UKFM Energy Hub, which earns a referral fee from installers who win work. This is the only commercial relationship in the network. We disclose it on every calculator's CTA paragraph.

The calculator results are the same regardless of whether you click through to UKFM. We do not adjust the numbers to drive conversions.

Updates

We update calculators on a quarterly cadence — pricing data, grant policy changes, tariff updates, methodology refinements. Major updates are noted in the methodology page changelog. We use semantic versioning on each calculator (v1.0, v1.1, v2.0).

Contact

Email [email protected] for: methodology questions, data corrections, partnership enquiries, journalist requests for citations or interviews. We respond within two working days.