Frequently asked questions

An Energy Performance Certificate (EPC) is the UK government's modelled energy-performance rating for a dwelling, shown as A (highest) to G (lowest). It is a model, not a meter — not a bill promise and not issued by Evolving Home. Look it up on GOV.UK Find an energy certificate.

A is the highest modelled efficiency and G the lowest. SAP maps a typical 1–100 energy-efficiency score into bands: A 92+, B 81–91, C 69–80, D 55–68, E 39–54, F 21–38, G 1–20. Band A is 92 and above, not capped at 100 (ONS, Energy efficiency of housing in England and Wales: 2024). Assessment method: GOV.UK SAP guidance. Many UK homes sit around D. For covered private lets, current MEES is generally E or better with exemptions — Band C as a 2030 PRS standard is not today's law. See rental energy standards and EPC Band C planning.

No. The certificate is modelled, not metered. Bills follow occupancy, tariffs, and how you run the heating system. Lowering boiler flow temperature or improving habits can cut costs without updating the stored EPC until you reassess.

Ten years in England and Wales. Install a heat pump or insulation and the official register will not change until you book a new accredited assessment.

Not reliably. The A–G band is still a cost-based SAP/RdSAP score. Electricity is expensive in that model versus gas, so a heat pump can leave the band flat or drop it even when kWh and carbon fall. In 2024, UK EPCs recommended a new fossil boiler in 120,000+ homes and a heat pump in none (Rosenow / RAP).

The recs list is the certificate's buy list, not ours. Use the EPC for fabric and heating facts. Do not buy a boiler or a heat pump because that page said so. A band change is not your bill. We are not an EPC. See our heat pump guide for cost and planning context.

No. Score, then claim the home, then Confirm facts. The Health Score is an indicative estimate for planning. It is not an Energy Performance Certificate, not a MEES certificate, and not a replacement for the official A–G rating. Start at Health Score.

NatHERS is Australia's Nationwide House Energy Rating Scheme. Home Energy Rating is the household-facing brand. DCCEEW is the Administrator. It produces a thermal star rating (0–10) for heating and cooling need, plus a separate Whole of Home score out of 100. See the official nathers.gov.au site.

No. Never collapse them. Stars (0–10) are thermal performance — heating and cooling need. Whole of Home (/100, and it can exceed 100) covers major appliances and onsite solar/batteries. Appliance efficiency is not in the star rating. Official Whole of Home guidance is on nathers.gov.au/whole-of-home.

It is a fair cousin, not a legal twin. Both are official modelled ratings. A UK EPC is required to sell or let most homes in England and Wales; NatHERS is the usual NCC (and often NSW BASIX) pathway for new homes and major renovations. Australia does not have a nationwide private-rented MEES twin on this page. Compare with our EPC rating guide.

No. There is no star ↔ Health Score 0–100 map. The Health Score is an Evolving Home estimate, not a NatHERS certificate. You can claim a Passport for an address anywhere. The Health Score needs a UK address. Confirm does not mint NatHERS stars.

No. Evolving Home is not NatHERS-accredited and does not claim an AU NatHERS adapter. For new-home assessments, accredited certificates show the scheme logo, colour formatting, and a QR code; non-accredited raters produce black-and-white certificates without the logo. Only NatHERS-accredited assessors can issue official existing-home certificates. Training certificates are not official assessments. Official existing-home certificate guidance covers that distinction. Check the live accredited-software list for tools (AccuRate Home, FirstRate5, BERS Pro, Hero, and Chenath versions).

Not as a nationwide sale/let mandate equivalent to a UK EPC. New homes and major renovations often need a NatHERS pathway rating for NCC compliance; NSW generally uses BASIX, which often includes the NatHERS star as an input. Existing-home ratings are information for buyers, renters, and upgrade planning. Re-verify after fabric or kit changes. Check current state rules — do not assume a 10-year UK EPC validity.

It can reduce heating demand, but the pound saving depends on your home type, existing fabric, occupancy, and tariff. Loft and cavity upgrades often help older UK homes; verify against your meter readings rather than assuming a fixed annual figure.

Not the same thing. Bills follow occupancy, tariff, and how you run the system. The A–G band is a cost-based SAP score and only updates after a new assessment. Insulation and controls can raise SAP; a cheaper bill or a heat pump can leave the band flat or drop it. Do not treat a lower bill as a higher EPC, or the certificate recs as a buy list. See our EPC rating guide for how bands map to scores.

The temperature of water leaving your boiler to heat radiators. Lowering it where safe can improve condensing-boiler efficiency—a low-cost step highlighted in Nesta's House Without Bills work alongside deeper retrofits.

Sometimes. Replacing oil, LPG, or direct electric heating is more likely to reduce costs than swapping a modern gas boiler, unless you have solar or a favourable electricity tariff. Read our UK heat pump guide for an honest cost comparison.

Plan from a full pre-grant whole-system quote, not a unit price. Editorial air-source planning ranges often sit around £8,000–£12,000 before a quote; ground-source work is commonly higher once groundworks are included. Emitters, hot water, electrical work and access can move the total. These are not Evolving Home prices and not a quote for your home.

In England and Wales the published standard BUS category for air-to-water and ground-source heat pumps is £7,500 (illustrative; eligibility is not assessed here). Residential air-to-air is £2,500. Eligible off-gas oil/LPG properties may receive £9,000 for air-to-water or ground-source heat pumps (time-limited; confirm on GOV.UK). Confirm the current category on GOV.UK and with an MCS-certified installer before subtracting anything.

A correctly designed heat pump can replace a fossil boiler where it meets the home's space-heating and hot-water demand. That is a design and quote question, not an automatic yes. BUS public guidance currently excludes hybrid heat-pump-plus-boiler packages and replacing an existing low-carbon system. EPC band C is not a universal BUS prerequisite.

Not guaranteed. Running cost depends on measured heat demand, delivered seasonal performance, standing charges and the electricity tariff you can actually take. Replacing oil, LPG or direct electric heating is more often favourable than swapping a modern gas boiler. Model time-of-use or heat-pump tariffs only if they are available to this property — we do not publish a universal saving versus gas.

There is no national payback year. Start from the full itemised install price, subtract only a BUS category confirmed by an MCS installer, then compare dated tariffs against measured fuel use. Finance, maintenance and performance sensitivity change the answer. Treat single-year payback claims as marketing until you have that calculation.

Yes, when they are correctly sized and commissioned for the property and local design conditions. Seasonal performance varies with weather, flow temperature, controls and use, so check the design assumptions rather than relying on a national average.

A government-supported loan, not a grant, for able-to-pay owner-occupiers and private landlords financing eligible low-carbon measures. DESNZ Scheme Rules (September 2026) describe an initial consumer launch from September 2026. It is distinct from Warm Homes: Local Grant, ECO4, and BUS. Apply is lender-led: the first lender participation window has closed, there is no single GOV.UK consumer apply form, and this page does not name live lenders or invent rates.

Scheme Rules say WHLS is intended to complement BUS (and the Home Energy Scotland Scheme). For example, an applicant in England or Wales installing a heat pump and applying for BUS can apply for a WHLS loan from a participating lender to cover eligible installation costs above the BUS grant received. Heat-pump and biomass loan caps are stated prior to BUS deduction. BUS eligibility is separate and is not assessed here — stacking is not automatic.

DESNZ Scheme Rules (September 2026) list loan caps of £15,000 for solar PV and for electrical storage batteries; £20,000 for air-to-water heat pumps (prior to BUS); £10,000 for air-to-air heat pumps (prior to BUS; Scheme Rules currently say air-to-air is not eligible until MCS certification exists); £35,000 for ground-source heat pumps (prior to BUS); £20,000 for biomass boilers (prior to BUS); £7,500 for heat-network connections; and £20,000 for micro-renewable systems. Caps are not a quote or an interest rate. This hub is the place we publish those official figures.

Not always free. ECO4 may fully fund some measures for some eligible households (income, tenure, and property criteria apply), but many households receive partial support or none — verify with scheme administrators. For BUS, if you are eligible the voucher typically covers part of a heat-pump install; you still pay any remaining cost and related upgrades. We do not determine eligibility or final customer contribution here.

There is no reliable cross-scheme approval time. GOV.UK says a council will usually contact a Warm Homes: Local Grant applicant within 10 working days for more information and a survey; that is not an installation or funding deadline. Ask the relevant administrator for the current evidence, approval and delivery timetable.

Some routes include private rented homes, including BUS and Warm Homes: Local Grant, but property, household, landlord-contribution and consent rules differ. Scheme inclusion does not mean a particular landlord or property qualifies.

Check the scheme's ownership rules, the lease, freeholder consent, planning and who owns communal fabric or heating before applying. Do not instruct external or communal work until the required permissions and funding approval are documented.

For most remaining halogen or incandescent fittings, yes — LEDs usually cost little upfront and use far less electricity for the same light. Payback depends on hours of use and your unit rate; high-use rooms recover cost fastest.

Modern LEDs with appropriate colour temperature and CRI can look excellent. Buy reputable lamps matched to the fitting; avoid the cheapest no-name bulbs if flicker or colour rendering matters to you.

Lighting upgrades can contribute in SAP-based modelling, but they rarely dominate a band change compared with fabric or heating. Treat LEDs as a low-regret efficiency and comfort upgrade, not a band guarantee.

Savings are highly home-specific. Well-used heating controls and tariff-aware scheduling often matter more than gadgets. Treat any single percentage claim as a planning range until you compare your own before/after meter data.

Usually no. A programmer, room thermostat, TRVs, and a usable smart meter or in-home display often deliver more value than multi-room lighting scenes. Buy systems you will actually configure and maintain.

Some heating-control packages can influence SAP-based EPC modelling when present and correctly specified. Bill savings and EPC movement are not the same thing — verify both with an assessor if the certificate is your goal.

Yes — panels produce from daylight, including cloudy conditions. Output depends on location, orientation, shading, system size, and inverter behaviour. Use site-specific estimates (installer PV modelling or PVGIS-style tools), not a single national kWh figure.

Evidence is mixed and market-dependent. A better EPC or lower running costs can support value in some sales, but there is no guaranteed percentage uplift. Treat value claims as marketing until you have local comparables and a surveyor view.

South is often best in the UK, but east/west can still be viable. Shading, pitch, and usable area often matter more than a perfect compass bearing. Ask for generation estimates for your actual roof planes.