Which Energy Improvements Can You Do Yourself?

The dividing line between a do-it-yourself energy improvement and one that needs a registered trade is not about difficulty. It is about notification. Draught-proofing, loft insulation and secondary glazing sit at the low-risk end, where the work is benign and reversible and no building control body needs to know. Electrical work sits on a different footing entirely: most repairs, replacements and maintenance jobs, and alterations or additions to existing circuits outside special locations, are non-notifiable, but extra power points or lighting points in a kitchen or bathroom, or outdoors, must be reported unless a registered competent person does them¹.

Solar panels and heat pumps are rarely householder jobs, and the reason is usually the electrical connection rather than the panel or the pump. Installing solar panels may require approval under the Building Regulations, and the associated electrical works are the trigger³. For Boiler Upgrade Scheme work, installers must be MCS certified and certified to install heat pumps or biomass boilers, so the grant route closes to a self-installer regardless of competence⁴.

The consequence of getting the boundary wrong falls on the owner, not the tradesperson. If you own the building, it is ultimately you who may be served with an enforcement notice if the work does not comply with the regulations¹. That single sentence shapes every decision on this page.

What counts as a DIY energy improvement, and what never should be

The measures that a householder can reasonably take on are the ones that change how a building loses heat without changing how it is serviced. Properly installed insulation, energy efficient windows and doors and reducing draughts can significantly reduce energy use, and reduce your energy bills⁶. Draught stripping for windows and doors is named in legislation as an energy-saving material, which places it firmly in the ordinary maintenance category rather than the regulated one⁷.

The measures that should never be treated as DIY are those that create, alter or extend a service. The Building Regulations will probably apply if you want to provide services and/or fittings in a building such as washing and sanitary facilities, hot water cylinders, foul water and rainwater drainage, replacement windows, and fuel burning appliances of any type¹. They may also apply to certain changes of use of an existing building¹. Replacement windows appear on that list, which surprises many householders who assume a like-for-like swap is exempt.

There is a second category that is not about competence at all: buildings where the fabric itself is the constraint. The energy efficiency of historic and traditional dwellings should be improved only if doing so will not cause long-term deterioration of the building's fabric or fittings⁸. For listed buildings, Listed Building Consent will be required for most energy efficiency works, including internal works such as internal wall insulation⁹. In conservation areas, energy efficiency will primarily be promoted using benign, reversible measures such as draught exclusion and secondary glazing⁹.

Draught-proofing, insulation and glazing: the low-risk end of DIY

This is where a householder's own labour is most defensible, and the reason is that the measures are reversible. Draught exclusion and secondary glazing are the two named as preferred in conservation areas precisely because they can be undone⁹. Draught stripping for windows and doors is listed as an energy-saving material in its own right⁷.

Loft insulation and cavity wall insulation are the measures most often asked about, and the honest answer is that the material is not the hard part. The Building Regulations set energy efficiency requirements that apply to building work, and Part 6 of the Building Regulations imposes additional specific requirements for energy efficiency¹⁰. Where insulation is installed as part of a wider alteration, that requirement bites. Where it is a straightforward top-up in an accessible loft, it generally does not.

The evidence on what actually prompts households to act is worth knowing before starting. Potential triggers for the installation of energy efficiency improvements were other building work (14%) or the heating system¹¹. In other words, most people do this work when something else has already opened up the building, which is also when the notification questions become live.

Glazing is the awkward one. Replacement windows appear in the list of work where the regulations will probably apply¹, so a window swap is not the same category as draught-proofing the window you already have. Secondary glazing, by contrast, is additive and reversible.

Electrical work: what Part P allows you to do yourself

The Building Regulations allow certain works, known as non-notifiable or minor work, to be carried out without having to notify building control or use a registered electrician². The scope is narrower than many householders assume. You do not need to tell them about repairs, replacements and maintenance work or extra power points or lighting points or other alterations to existing circuits, except in a kitchen or bathroom, or outdoors².

Where the work is notifiable, it must be reported to the local building control body unless completed by someone registered on the competent person scheme¹². The electrician must be registered by an organisation authorised by the Secretary of State and able to certify the work as safe without notifying Building Control². That is the whole point of the scheme: the certification travels with the trade, not with the householder.

There is a limit to what the regulations cover. The Building Regulations do not set standards for the safety of electrical appliances but they do require that fixed connections of appliances are safe². So the appliance itself is a product safety matter; the connection to the installation is a building regulations matter.

Safety can be checked in either of two ways: by using an electrician registered with a competent person scheme, or by notifying the building control section of the local authority². Both routes end in the same place, a certificate that the work is safe. Only one of them lets a householder do the work.

Notifiable or not: when electrical work must be reported or certified

The test is location and circuit, not difficulty. Most repairs, replacements and maintenance jobs, and alterations or additions to existing circuits outside special locations, are non-notifiable¹. A kitchen or bathroom counts as a special location, and so does anything outdoors².

Solar changes the picture. All electrical work comes under Building Regulations and is notifiable to the local authority¹³. That is a broad statement, and it is the reason a self-installed array runs into trouble at the connection stage rather than at the mounting stage.

The practical sequence for notifiable work is short and unforgiving:

1. Confirm whether the work is notifiable, by location and by whether it creates a new circuit.
2. Notify the building control body or a registered third-party certifier before work starts¹.
3. Either use an electrician registered on a competent person scheme, who can self-certify, or have the local authority inspect².
4. Keep the certificate with the property paperwork.

The reason this matters beyond compliance is that a future buyer, a solicitor or an insurer may ask for it. A certificate that does not exist cannot be produced later.

Building regulations: the rules that apply even to your own home

Owner-occupation is not an exemption. The Building Regulations will probably apply if you want to put up a new building, extend or alter an existing one, or provide services and/or fittings in a building such as washing and sanitary facilities, hot water cylinders, foul water and rainwater drainage, replacement windows, and fuel burning appliances of any type¹. They may also apply to certain changes of use of an existing building¹.

Energy efficiency has its own layer. Part 6 of the Building Regulations imposes additional specific requirements for energy efficiency¹⁰. For new dwellings, the dwelling primary energy rate, dwelling emission rate and dwelling fabric energy efficiency rate must not exceed their respective target rates⁸. Those are design-stage targets for new build, but they set the standard against which alterations are judged.

Where a building is historic, the requirement is qualified rather than removed. The work should comply with standards in this approved document to the extent that it is reasonably practicable¹⁰. That is a real obligation with a reasonableness test attached, not a waiver.

The enforcement mechanism is what gives all of this teeth. If building regulations approval is not given, then the work should be changed so it meets standards¹². There is no route that ends with the work staying as it is.

Solar panels and heat pumps: why these are rarely DIY jobs

Two separate obstacles stand in the way, and neither is about whether a competent householder could physically mount a panel.

The first is building regulations. Installing solar panels may require approval under the Building Regulations³, and the associated electrical works are the reason³. Regardless of whether or not planning permission is required for the installation of your solar panels, the installation itself is still subject to standard building regulations¹³. Planning and building control are separate regimes, and clearing one does not clear the other.

The second is scheme eligibility. Installers must be MCS certified and be certified to install heat pumps and/or biomass boilers⁴. Where a grant is involved, the property owner must become the legal owner of the heat pump or biomass boiler once the installation is complete¹⁴. A self-installed system has no MCS-certified installer behind it, so the certification route that schemes rely on is absent.

Planning is the easier half. Installing solar panels and equipment on residential buildings and land may be permitted development with no need to apply to the council for planning permission¹⁵. If you believe installing solar panels would be lawful under the permitted development regulations, and you require written confirmation, you can submit an application for a lawful development certificate¹⁵. Installing solar panels may also require approval under the Building Regulations⁶.

MCS certification: what it means and when you need a certified installer

MCS is a certification scheme for microgeneration installation companies and products⁴. It is the mechanism by which a householder's installer becomes traceable to a standards body rather than to a directory listing.

Its reach is narrower than the name suggests. MCS requires installers to provide a design-stage prediction of system efficiency, not verify actual performance, and third party non-modulating controls are not prohibited¹⁶. So certification tells you the installer followed a defined process; it does not tell you the system will perform as predicted.

There is oversight beyond the installer's own paperwork. MCS also undertake their own checks on installations completed by MCS-certified installers, separate from Ofgem's audit programme¹⁷. Property owners contacted for those checks should aim to respond within seven days¹⁴.

Where something goes wrong, MCS is the contact for issues with the installation process, the installer, or the MCS certificate or product⁵. The window is finite: for MCS certified installations, it is no more than two years after the date that the system was commissioned⁵.

Scheme rules also impose deadlines on the installer rather than the householder. No later than 10 working days after commissioning, the installation shall be registered by the MCS Contractor on the MCS Installation Database, and MCS Commissioning certification is to be issued to the Employer within 14 days of commissioning¹⁸. Those are the dates to check against if certification has not arrived.

Who carries the legal responsibility: owner or builder

The answer is uncomfortable and consistent. If you are the owner of the building, it is ultimately you who may be served with an enforcement notice if the work does not comply with the regulations¹. Employing a competent trade does not transfer that exposure.

Responsibility for documentation is split differently. Where a building is under construction it is the responsibility of the person who carries out the construction to provide the energy performance certificate¹⁹. If it is being rented, then it is the responsibility of the landlord to provide the EPC to the potential tenant¹⁹. For furnished holiday lets, the occupier is responsible for meeting the energy costs for the property¹⁹.

Grant-funded work adds an ownership condition. The property owner must become the legal owner of the heat pump or biomass boiler once the installation is complete¹⁴. That is a condition of the funding, not a suggestion.

What happens if the work does not comply

The immediate consequence is remedial. If building regulations approval is not given, then the work should be changed so it meets standards¹². In practice that means reopening the work, and the cost of doing so sits with whoever commissioned it.

There is a second consequence that is easy to miss: it can affect what the property is entitled to. Where the Energy Efficiency Requirement applies to a Feed-in Tariff installation and is not satisfied, the lower tariff is to be assigned to the installation²⁰. A Display Energy Certificate will not be accepted as proof of meeting the EER²⁰. So a compliance gap can reduce a payment stream, not just trigger an inspection.

For landlords, the minimum energy efficiency regime has its own exemptions, and they are narrow. The requirement to meet the minimum level of energy efficiency (EPC E) does not apply where a landlord has made all the relevant energy efficiency improvements for the property, or there are none that can be made, and the property remains below EPC E²¹. Regulation 31 provides a further exemption where the landlord has, within the preceding five years, been unable to increase the energy performance indicator as a result of the tenant refusing consent, or third party consent being refused or granted subject to a condition with which the landlord cannot reasonably comply²².

Where a scheme funded work, the funding body may have had no role in it. We did not pay for, choose, or install the energy efficiency improvements²³. That is a statement about liability as much as about administration.

England, Scotland, Wales and Northern Ireland: where the rules differ

The building regulations regimes are separate, and the differences matter most for electrical work and for energy performance duties.

In England and Wales, if you are carrying out electrical work in your home or garden, you will have to follow new rules². Wales publishes its own building regulations guidance on electrics²⁴, and has consulted on its own Approved Document L volume for dwellings¹⁰. The Welsh energy performance picture is tracked separately, and the dashboard does not take into account properties that are exempt from the Minimum Energy Efficiency Standards²⁵.

Scotland runs a distinct system. The Building Standards Technical Handbook for domestic work sets out Section 6 Energy (EC, energy, economy and heat retention)²⁶. Scotland's housing stock performs comparatively well: the average energy efficiency ranking places it second highest, after Northern Ireland, followed by Scotland and England, with the lowest average rating in Wales²⁷. Scotland also has its own constraints on communal work: works to install communal zero emissions heating systems, and certain communal energy efficiency works not deemed maintenance, are considered improvements and require unanimous approval from owners²⁸. Certain energy efficiency measures may never be cost effective in terms of payback times for owners and will require additional support²⁸.

Northern Ireland has its own building regulations, amended by Regulation 43 of the Energy Performance of Buildings (Certificates and Inspections) Regulations (Northern Ireland) 2008²⁹. Those regulations implement Articles 7, 9 and 10 of the Energy Performance of Buildings Directive 2002/91/EC²⁹.

Where DIY stops being sensible

The pattern across the sources is consistent. Work that maintains the building, is reversible, and does not create or alter a service is generally open to a householder. Work that creates a circuit, connects a generating source, or replaces a controlled fitting is not, and the reason is the certificate rather than the competence.

There is also a limit on what certification itself delivers. Energy Performance Certificate ratings do not always capture the true efficiency of a retrofit; measures like PV panels or air-source heat pumps may improve an EPC score but fail to address fundamental building issues such as poor insulation or moisture risks³⁰. A householder who does the low-risk work well, and brings in registered trades for the notifiable work, ends up with a building that performs better than its certificate suggests rather than one that scores well and performs badly.

For a household's energy independence, the split is straightforward. Draught-proofing, loft insulation and secondary glazing reduce demand and depend on nothing outside the home. Solar and heat pumps reduce dependence on a supplier and on gas, but they introduce a new dependence: on an MCS-certified installer, on a scheme administrator, and on a certification database that has to be updated within ten working days of commissioning¹⁸. That is a real trade, and it is worth naming plainly.

If the sequence of work is the open question rather than the division of labour, what order home energy improvements should be done in sets out the logic, and the paperwork to keep from every energy improvement covers what to retain once each stage is signed off.