What Should You Do First to Make a Home More Energy Efficient?

The first step is not a purchase. It is reading the home's Energy Performance Certificate, which official guidance describes as a good starting point for improving the energy efficiency of a property¹. The certificate explains how energy efficient a building is and how it could be improved², giving an assessment of the home's efficiency³ along with its heating source, estimated carbon emissions and estimated energy cost. Attached to it is a recommendation report listing cost effective measures, from low energy bulbs to upgrading insulation, each with an indication of cost and typical savings.

The second step is to see what the house actually uses, rather than what a model says it should. A smart meter measures gas and electricity use and sends the data to the supplier, and comes with an in-home display showing how much energy is being used during the day. There is no direct cost for the meter itself. The third step is the set of adjustments that cost nothing: turning a thermostat down one degree, from 22 to 21 degrees, is estimated to save around £120 a year in Great Britain, or £80 in Northern Ireland⁴.

Only after those three does spending make sense, and the reason is the size of the sums involved. In England in 2024, the estimated average cost to improve dwellings to at least energy efficiency band C was £7,480 across all tenures⁵. Against a figure like that, a £50 to £150 certificate⁶ and a free meter⁷ are cheap ways to find out which part of the £7,480 the house actually needs.

Start with the EPC: the assessment that shows where the home stands

Energy Performance Certificates are the basis of many energy efficiency policies in the domestic built environment¹¹, which is why so much else, grants, rental rules, targets, is expressed in their language. For a householder the practical value is narrower and more useful: the certificate gives information about the energy efficiency of a property, as well as its heating source, estimated carbon emissions and estimated energy cost¹².

Assessors determine the rating using the standard assessment procedure (SAP), with a reduced version, RdSAP, used for existing homes where full information may not be available¹³. That matters for expectations. A reduced procedure fills gaps with assumptions, so a certificate is a modelled standardised comparison rather than a measurement of the particular household's behaviour. It tells what the building is likely to need; the meter tells what the household actually does.

The Energy Efficiency Rating is the first rating to appear on the certificate and is required in adverts for sale or rental, showing both a current and a potential rating¹⁴. The potential figure is the one most often misread: it is what the modelling expects if the recommended measures are carried out, not a promise.

Most homes already have a certificate, because one must be provided when a building is advertised for sale or for let to a new tenant¹⁵. Prospective buyers and tenants are entitled to see it at no cost, and a buyer receives a copy from the seller that can be reused within its period of validity¹⁶. That makes the first step free for a large share of households. Reform is under way: an independent advisory letter on domestic rating metrics recommends four primary metrics in real-world units, covering total energy use intensity (kWh/m2/yr), space heating demand intensity (kWh/m2/yr), heating system type ranked in six categories, and energy cost intensity (£/m2/yr)¹⁷. A householder starting now works with the certificate as it stands while knowing the metrics are being revised.

More detail on reading the document sits in using an EPC and its recommendation report to plan improvements.

What the EPC tells you: bands, costs and the improvement report

Certificates rate how energy efficient a building is, with ratings from band A (very efficient) to band G (inefficient)¹⁷. Band C is the pivot in policy. The UK government's stated aspiration is for as many homes as possible to reach band C by 2035, where practical, affordable and cost effective¹⁸, and the same band is used as the target in later policy statements on the rented sector¹⁹.

The most useful page is not the coloured graph but the recommendation report behind it, which lists measures that could improve efficiency together with an indication of cost and typical savings for each improvement over three years¹⁴. It is also the page most people never reach: among those aware of certificates, 32 per cent recalled seeing the section recommending ways to improve energy efficiency, in the winter 2025 attitudes tracker²⁰. Each certificate comes with that report, covering measures from low energy bulbs to upgrading insulation¹⁶.

The certificate is valid for a maximum of ten years or until another is commissioned for the same building, whichever comes sooner⁸. Cost varies from one company to another depending on the size, location and age of the building⁸, and is usually in the £50 to £150 range⁶.

Insulation first: the walls and roof are where most of the heat goes

The reason assessment tends to point at fabric before machinery is arithmetic. An un-insulated dwelling loses a third of all its heat through the walls and a further quarter through the roof⁹. Independent guidance puts the same figure on walls: around a third of all the heat lost in an uninsulated home escapes through them⁴.

A building losing that much heat needs a larger heating system, burns more fuel at any given thermostat setting, and gets less from any low-carbon technology installed later. That is the whole logic of a fabric first approach, and it is also why the order of work matters: see what order home energy improvements should be done in and where a UK home loses heat.

For independence, fabric is the only measure that reduces demand outright. Insulation does not depend on a supplier, a tariff, an app or a manufacturer's servicing. Once installed it keeps working with no account attached to it. Every other measure discussed here changes how energy is bought, monitored or generated; insulation changes how much is needed in the first place. The trade-off is that it is the least visible spend and often among the more disruptive to install.

Measure before you manage: what a smart meter shows

A smart meter automatically sends electricity and gas meter readings to the supplier⁷, and readings travel over the Data Communications Company's secure network²¹. The immediate effect is administrative rather than physical: bills are based on accurate meter readings and not estimates, readings do not have to be submitted by hand, and more flexible tariffs, including dual-rate tariffs, become accessible²². In prepayment mode, credit can be added automatically or without visiting a shop²².

The part that bears on efficiency is the in-home display. Smart meters come with one so consumers can see and manage energy use²³, and it shows how much energy is being used during the day⁷. Official guidance in Wales describes the display as helping households monitor and manage consumption¹⁰. The data shared through the meter is used to bill for energy used, to offer new products and services such as new tariffs where permission has been given, and to help make the energy system more efficient by recording demand more accurately²².

That last point is worth naming plainly: the meter serves the supplier and the system as well as the household. Data flows outward. The household's gain is visibility, and visibility only turns into savings if something changes as a result. Guidance puts it no more strongly than that a household could find ways to save money using up-to-date information on its energy use⁷.

Working out consumption is covered further in working out how much energy your home uses before you spend.

Smart meters are free, but they do not save money on their own

There is no direct cost for a smart meter; any expenses are recouped through energy bills over time, and installation, typically about 90 minutes, is free of charge¹⁰. Suppliers provide them free on request⁷. The installation should cause minimal disruption, key safety checks should be carried out during the appointment, and an in-home display should be offered and demonstrated²³.

The limits are equally concrete.

• A meter may stop recording the energy used, or may continue recording but stop sending readings to the supplier²². Since accurate readings are what displace estimates, a transmission fault means billing can fall back on estimates until readings are supplied.
• On a change of supplier, a second-generation meter keeps all its smart functions with no interruption; a first-generation meter may lose some smart functionality²⁴.
• Where a supplier ceases trading, the meter may not work in smart mode with the new supplier, and readings may have to be taken and submitted manually; it may return to smart mode after a later change of tariff or supplier²⁵.
• Households with solar panels or other renewable generation can still have a meter installed, but some suppliers are not yet ready to supply smart meters to those customers²⁴.

Thermostat and habits: the adjustments that cost nothing

Turning a room thermostat down by one degree, from 22 to 21, is estimated to save around £120 a year in Great Britain or £80 in Northern Ireland⁴. The gap between the two figures reflects different energy prices and heating fuels rather than different physics, and it is a useful reminder that saving figures are tied to the tariff and fuel behind them.

Adjustments of this kind belong at the start for three reasons: they carry no capital cost, they can be reversed if the house becomes uncomfortable, and they establish what the household is prepared to live with before money is committed to equipment sized for a different set of habits. Free advice services in Wales publish consumer-body tips on cutting bills alongside the certificate guidance⁶, and Northern Ireland publishes its own energy efficiency tips²⁶.

Further no-cost and low-cost measures are collected in no-cost and low-cost ways to cut energy use first and how much changing habits can save.

Grants and free advice across the four nations

Free, impartial advice exists in every nation, and in most cases it is the correct second call after reading the certificate, because it is the route to funding as well as guidance.

Independent guidance on room-by-room green renovation is also published by the Energy Saving Trust²⁸. Nation-specific detail is set out in free home energy advice in Scotland, in Wales, in Northern Ireland and in England, and the sequencing question is covered in checking what grant help you can get before you start work.

Renting or selling: the rules that change the starting point

A certificate must be provided when a building is advertised for sale or for let to a new tenant¹⁵. For landlords there is more than a disclosure duty. Guidance for landlords of domestic private rented property refers to the 2018 Minimum Level of Energy Efficiency standard, set at band E³⁷: no property without at least a rating of E or above can be rented out unless an exemption applies³⁸.

That floor is under revision, and the documents describe the change at different stages. The UK government has proposed raising the minimum standard required of privately rented homes in England and Wales to the equivalent of band C by 2030³⁹, with a 2025 consultation setting out the same target and proposing that properties with a current band C be recognised as compliant under the future standard until that certificate expires⁴⁰. A later government response describes preventing landlords from renting out homes below a rating of C or equivalent¹⁹. A 2026 roadmap update states the requirement as a minimum score of band C against the fabric performance metric and either the heating system or smart readiness metric, from 1 October 2030⁴¹. In Scotland, the intention stated in earlier policy was to require private rented properties to reach a standard equivalent to band C where technically feasible and cost effective at change of tenancy⁴².

Tenants have a narrower but real starting point. A private renter can choose to have a smart meter if the energy bills are in their name or they prepay for energy, after checking the tenancy agreement and letting the landlord know⁴³. More generally, any household that pays for energy, owner or renter, should be able to book an installation where a meter is expected to work at the property²³. Further detail is in where to start if you rent your home, and sellers may want is it worth improving a home's energy efficiency before selling.

After the first steps: building a plan rather than buying a product

Once the certificate has been read, the meter is showing daily use and the free adjustments are made, the question becomes sequence and budget. The Northern Ireland tool is explicit that its output is an action plan rather than a quotation³³, and referral services in England work the same way, passing households on to insulation or heating measures rather than selling them³⁴. Independent guidance on green renovation approaches a house room by room, putting efficiency first²⁸.

Two figures should shape that plan. The average estimated cost of improving a dwelling in England to at least band C was £7,480 across all tenures in 2024⁵, and the national aspiration is band C by 2035 where cost-effective, practical and affordable¹⁸. Those caveats are load-bearing: the target is conditional on cost-effectiveness for a reason, and a plan for a particular house has to test each measure against that house rather than against the average.

For independence, the honest summary is that these first steps improve information and reduce waste, but they do not remove dependence. The certificate is a modelled document produced under a government procedure. The smart meter reports to a supplier over a network operated by a third party, and can drop out of smart mode when a supplier changes or fails²⁵. Grants come with eligibility rules set by government. Only the fabric measures those first steps point towards, walls, roof, draughts, cut the amount of energy the house needs at all. The assessment stage is the cheapest way to find out which of those is worth doing, and in what order.

Next steps are set out in whole house plans and who writes one, payback periods for home energy measures compared and the overview in Getting Started with Home Energy.