Future Homes Standard 2026: What It Means for Extensions and New Homes
The way homes are designed and built in England is changing.
The Government has now published the Future Homes and Buildings Standards, introducing updated requirements for energy efficiency, heating systems, ventilation and renewable electricity generation.
Although the principal changes do not come into force until 24 March 2027, homeowners, developers and architects designing projects during 2026 should already be considering their impact. A project designed today may not reach the Building Regulations submission or construction stage until the new standards apply.
For anyone considering a house extension, loft conversion, new build or residential development, early planning will be increasingly important.
What is the Future Homes Standard?
The Future Homes Standard is a major update to the Building Regulations in England.
Its purpose is to ensure that new homes are constructed with high levels of energy efficiency and low-carbon heating so that they will not require significant retrofitting as the electricity grid continues to decarbonise.
The changes include revised guidance under:
- Approved Document L: Energy and Greenhouse Gas Emissions
- Approved Document F: Ventilation
- The Building Regulations relating to fixed building services
- A new requirement for on-site renewable electricity generation in new dwellings
The regulations are intended to make new homes more efficient, reduce operational carbon emissions and improve the quality of information given to homeowners about their property.
When do the new regulations take effect?
The updated requirements are scheduled to come into force on 24 March 2027 for most residential projects in England.
Transitional arrangements may allow the previous standards to continue where a valid building notice, initial notice or full plans application has been submitted before that date. However, the relevant building work must then commence before 24 March 2028.
Simply obtaining planning permission will not secure the earlier Building Regulations requirements. Planning permission and Building Regulations approval are separate processes, and it is the timing of the building control submission and commencement of work that will normally determine which technical standards apply.
This makes the programme particularly important for new-build homes and residential developments that are currently at feasibility or planning stage.
Will new homes need solar panels?
One of the most significant changes is the introduction of a new functional requirement known as L3.
This will require a system of on-site renewable electricity generation when a new dwelling, or a building containing dwellings, is constructed. In most conventional residential projects, photovoltaic solar panels are likely to be the most practical way of meeting this requirement.
Solar provision should therefore be considered from the beginning of the design process rather than added to the roof as an afterthought. Roof orientation, pitch, overshadowing, rooflights, dormers, chimneys and plant locations can all influence how effectively renewable technology can be incorporated.
A coordinated architectural design can integrate solar panels more successfully while maintaining the appearance and character of the building.
Will gas boilers still be permitted in new homes?
The Future Homes Standard is centred around low-carbon heating and significantly improved energy performance.
For many new homes, heat pumps are expected to become the principal heating solution. Their successful use depends on more than selecting a piece of equipment at the end of construction.
A heat-pump system works most effectively when it is supported by:
- A well-insulated and airtight building envelope
- Appropriately sized radiators or underfloor heating
- Carefully calculated heat losses
- Suitable external plant positioning
- Effective heating controls
- Coordinated hot-water storage and services
The updated guidance also places greater emphasis on heat-pump controls, insulation to heating distribution systems, commissioning and compliance with manufacturers’ installation requirements.
These matters should be coordinated between the architect, energy assessor, mechanical designer, contractor and building control body.
What does the Future Homes Standard mean for house extensions?
The headline requirements for renewable electricity generation relate primarily to the construction of new dwellings. An ordinary extension to an existing house will not automatically be treated in the same way as a new home.
However, extensions must still comply with the applicable requirements of Approved Document L.
The 2026 edition identifies three principal ways of demonstrating compliance for an extension:
- The elemental method
- The area-weighted method
- An assessment using the Standard Assessment Procedure
New walls, floors, roofs, windows, rooflights and doors must meet the relevant thermal-performance standards. Heating, ventilation and other fixed building services installed or extended as part of the project must also satisfy the applicable requirements.
The correct compliance route will depend on the design, the amount of glazing and the condition and performance of the existing house.
Can an extension still have large areas of glazing?
Large sliding doors, bi-fold doors and rooflights remain popular features of contemporary extensions. However, extensive glazing can increase heat loss during winter and the risk of overheating during summer.
Under the elemental approach, the total area of windows, roof windows, rooflights and doors in an extension should generally not exceed:
- 25% of the extension’s floor area; plus
- The area of existing doors and windows that are removed or enclosed because of the extension
This does not mean that larger areas of glazing are prohibited. Alternative calculations can demonstrate that enhanced insulation or improved performance elsewhere compensates for the additional glazing. A Standard Assessment Procedure calculation may also be used to compare the completed house and extension against a compliant notional design.
This is one reason why glazing decisions should be tested during the design stage rather than after planning permission has been granted.
Ventilation and overheating must be considered together
Increasing insulation and airtightness can reduce heat loss, but it also makes ventilation strategy more important.
A successful low-energy home needs to balance:
- Heat retention
- Fresh-air supply
- Moisture control
- Indoor air quality
- Summer overheating
- Solar gain
- Occupant comfort
Adding larger windows is not always the complete solution. Window orientation, opening positions, cross-ventilation, solar shading and mechanical ventilation may all need to be considered.
The best-performing homes are designed as coordinated systems rather than as a collection of individual products.
What should homeowners do now?
Homeowners planning work during 2026 or 2027 should establish a realistic design, approval and construction programme as early as possible.
Before progressing, it is sensible to consider:
- Whether planning permission or permitted development applies
- When the Building Regulations application will be submitted
- Whether transitional arrangements could apply
- The proposed insulation and airtightness strategy
- The extent and performance of glazing
- Heating and hot-water requirements
- Ventilation and overheating risks
- Roof space and orientation for renewable energy
- The effect of technical requirements on the project budget
Trying to resolve these matters after a contractor has started work can result in delays, redesign and unexpected costs.
Designing a home for long-term performance
Building Regulations establish minimum legal standards. They should not necessarily be treated as the limit of good design.
A carefully designed extension or new home can provide:
- Lower energy demand
- More comfortable internal temperatures
- Better natural light
- Improved indoor air quality
- Reduced reliance on fossil fuels
- Greater resilience against future energy costs
- A more attractive and valuable property
The aim should not simply be to pass Building Regulations. It should be to create a home that works efficiently, feels comfortable and continues to perform well for many years.
Planning an extension or new home?
Hepburn Architects works with homeowners and residential developers throughout Birmingham, the West Midlands, Middlesbrough, Teesside and across the UK.
We can assess your property, develop the architectural design, prepare planning applications and produce coordinated Building Regulations drawings that respond to the latest technical standards.
Contact Hepburn Architects to arrange an initial consultation and discuss the potential of your property.
This article was reviewed in July 2026 and provides general guidance for projects in England. The requirements applying to an individual project should be confirmed with the appointed design team and building control body.