What the 2027 Future Homes Standard Means for Self-Builders and Replacement Homes in Cornwall

Information checked: 24 August 2026.

If you are beginning a self-build or replacement home now, there is a practical question to resolve early: which energy standard should shape the design if the project reaches Building Control during the 2027 transition?

The Future Homes and Buildings Standards were published by the Government on 24 March 2026. For most new homes in England, the new requirements come into force on 24 March 2027. They bring higher expectations for energy efficiency, low-carbon heating and on-site renewable electricity generation.

For clients, however, this is not simply a question of meeting a new set of calculations. Decisions about building form, orientation, glazing, ventilation, heating and renewable energy affect the architecture from the beginning. Leaving them until technical design can restrict choices, create redesign work and make the final strategy feel added on rather than integrated.

This guide explains the principal dates, what the changes may mean for self-builders and replacement dwellings, and how the national standard sits alongside Cornwall’s planning requirements.

What changes on 24 March 2027?

The Future Homes Standard updates the energy-performance requirements for new homes in England. Its purpose is to create homes with low-carbon heating and high levels of energy efficiency so they should not require later retrofitting to become zero-carbon in use as the electricity grid decarbonises.

The 2026 amendments include a new requirement for on-site renewable electricity generation when a new dwelling, or a building containing a dwelling, is erected. The Government’s published material indicates that solar panels will form part of the approach for the majority of new homes, although the appropriate system must respond to the design of the building and its surroundings.

The revised guidance also addresses low-carbon heating systems, heat-pump controls, ventilation, commissioning, energy storage and the information that should be provided to the homeowner. These are connected decisions. A heating system cannot be considered properly without understanding heat loss; airtightness cannot be considered without ventilation; and solar generation cannot be integrated well if roof form, orientation and shading have already been fixed.

For a fuller explanation of the relationship between energy modelling, individual building elements and real comfort, read The Architecture of Comfort: SAP, U-Values and Thermal Performance.

SAP 10.3 will initially be used

The Government originally expected the Home Energy Model, or HEM, to be introduced alongside the Future Homes Standard. Its launch has since been delayed while further assurance work is completed.

SAP 10.3 will therefore initially be the approved methodology for demonstrating compliance for new dwellings. This matters because early modelling gives the architect, energy assessor and client a way to test the home as a complete system rather than treating insulation, glazing, heating and renewable technology as separate specifications.

It is also important not to treat one U-value or one product as proof of compliance. SAP assesses the dwelling as a whole, and the appropriate strategy depends on its form, orientation, construction, services and site.

The transition should be treated as a programme and design decision, not simply as a deadline. The earlier the energy strategy is tested, the more naturally it can shape the architecture.

Which projects may use the transitional arrangements?

The principal date for most new-home projects is 24 March 2027, but the regulations include transitional provisions.

For non-higher-risk work, the new changes will generally not apply to work on an individual building where:

1. a building notice, initial notice or application for building control approval with full plans has been given to the relevant authority before 24 March 2027; and
2. the work covered by that notice or application is commenced on that building before 24 March 2028.

Both parts matter. Planning permission alone is not the same as making the relevant Building Control submission, and submitting information before the first date does not provide indefinite protection if the work is not commenced within the transitional period.

The regulations also use defined terms for the type of submission, the relevant authority and what constitutes commencement. A project’s position should therefore be confirmed with its architect, Building Control body and energy assessor rather than assumed from a general timeline.

Higher-risk buildings follow different dates and procedures and are outside the scope of this homeowner-focused guide.

Does the Future Homes Standard affect self-build and replacement homes?

A self-build route does not remove the need to comply with Building Regulations. Where an existing house is demolished and a new replacement dwelling is erected, the new home will generally be treated as a new dwelling for these energy-performance requirements.

That makes programme planning especially important for replacement projects. Planning, demolition, discharge of conditions, technical design and Building Control approval can all affect when work is genuinely ready to begin. A planning approval obtained before March 2027 should not be assumed to secure the earlier energy standard.

Extensions, alterations and refurbishments can fall under different provisions. Clients considering whether to improve an existing building or replace it should establish the regulatory route before using the transition dates to make a decision.

ARCO2’s guide to Replacement Dwellings in Cornwall explores the wider architectural, planning and performance questions behind that choice.

What should change at design stage?

The most useful response to the Future Homes Standard is not to begin with a list of products. It is to develop an energy and comfort strategy alongside the architecture.

Building form, orientation and glazing

A compact form can reduce the area through which heat is lost, but a home must also respond to views, access, landscape and its internal programme. Glazing can provide daylight, solar gain and a strong connection to the setting, yet too much unprotected glass can increase heat loss in winter and overheating in summer.

Orientation, window proportions, external shading and room arrangement should therefore be tested together. On a sensitive or exposed Cornish site, these decisions must also respond to privacy, wind, salt, driving rain and the visual impact of the building.

Insulation, airtightness and thermal bridges

Insulation works best as a continuous layer. Junctions around floors, walls, roofs, windows and structural elements need careful coordination so that avoidable thermal bridges are designed out rather than discovered during construction.

Airtightness helps reduce uncontrolled heat loss, but a highly airtight home also needs a properly designed ventilation strategy. The aim is not simply a low test result: it is consistent comfort, controlled fresh air and a building envelope that performs as the design intended.

ARCO2’s Passive House Principles for Low Energy Homes in Cornwall explains how fabric-first thinking brings these elements together.

Heating, hot water and ventilation

The Government’s direction is towards low-carbon heating. Its consultation response indicates that fossil-fuel heating systems are not expected to meet the Future Homes Standard, while the final guidance includes specific provisions for heat pumps and low-carbon heat networks.

That does not mean the heating system should be selected in isolation. Its size and operation depend on the heat demand created by the fabric, glazing, airtightness and ventilation. Plant space, hot-water storage, controls, distribution temperatures, external equipment and maintenance access can all influence the design.

The correct solution remains project-specific and should be modelled and specified by the competent members of the design team.

Renewable electricity as part of the architecture

The new on-site renewable electricity requirement makes early consideration of roof form and solar access even more important. Photovoltaic panels are most convincing when they are part of the architectural composition, not an awkward late addition to a roof designed without them.

Orientation, roof geometry, landscape visibility, shading, electrical infrastructure and any future storage strategy should be discussed while the design can still respond naturally.

Cornwall adds a separate planning layer

Building Regulations and planning policy perform different roles. A design may need to demonstrate compliance with the national energy standard while also satisfying Cornwall’s local planning requirements.

Cornwall Council’s Climate Emergency Development Plan Document forms part of the local planning framework. The Council specifically advises that Policy SEC1 should be considered at an early design stage because orientation, architectural form, landscaping and materials all have implications for energy performance.

Current application guidance also directs applicants towards SEC1 energy statements and the Council’s SAP and PHPP energy-summary tools. Depending on the proposal, the planning process may therefore require energy information before the Building Regulations position is finalised.

This is why energy strategy and planning strategy should not be developed in separate rooms. A technically efficient building still has to belong to its landscape, respond to heritage and local character where relevant, and present a coherent case through planning.

The two systems should be coordinated for the individual site. Meeting one requirement should not be assumed to satisfy the other.

Compliance is not the same as comfort

Building Regulations set minimum legal requirements. They are essential, but a compliance result cannot by itself describe everything a client will experience in the completed home.

Comfort depends on how the building works throughout the year: whether internal temperatures remain stable, whether rooms receive useful daylight without excessive summer heat, whether fresh air is supplied without draughts, and whether internal surfaces feel warm rather than cold.

Durability also matters. Insulation continuity, airtightness and services must survive the move from the model to drawings, procurement and construction. Commissioning then needs to confirm that ventilation, heating, controls and renewable systems operate as intended, while clear handover information helps the homeowner use them effectively.

This is the difference between treating sustainability as a calculation and embedding it in the architecture. ARCO2’s broader approach is explored in Sustainable Architecture in Cornwall.

Ladybird Farm: making the decisions work together

Ladybird Farm provides a useful example of energy, carbon and place being considered as parts of one design problem.

The project sits beside a listed walled garden in St Tudy. Its rural and historic setting required a contemporary home that could improve comfort and long-term performance without losing its connection to place.

ARCO2’s published project studies explore how orientation, fabric, glazing, shading and photovoltaic generation were considered alongside embodied, operational and whole-life carbon. The lesson for clients approaching the 2027 transition is not that Ladybird Farm was assessed against a later regulation. It is that performance decisions become more coherent when they are made early enough to influence the architecture.

Read more about Low Carbon Home Design at Ladybird Farm and the project’s ICF construction strategy.

What should a client starting now do?

Frequently asked questions

When does the Future Homes Standard start?

For most new-home work in England, the relevant amendments come into force on 24 March 2027. Different arrangements apply to higher-risk building work.

Can a project submitted before March 2027 use the earlier standard?

Potentially. For non-higher-risk work, the transitional provisions generally require the relevant building notice, initial notice or full-plans Building Control application to be made before 24 March 2027 and the work on the individual building to be commenced before 24 March 2028. The project’s exact position should be confirmed with Building Control.

Does planning permission secure the transitional arrangement?

No. Planning permission and Building Control approval are separate processes. The transitional wording refers to specified Building Control submissions and commencement of the relevant building work, not simply the date of planning consent.

Will gas boilers be permitted in new homes?

The Government’s stated approach is based on low-carbon heating, and its consultation response says fossil-fuel heating systems are not expected to meet the Future Homes Standard. Compliance is assessed through the whole-dwelling methodology, so a project’s solution should be confirmed through current guidance and modelling rather than reduced to a single-product rule.

Is SAP being replaced by the Home Energy Model in March 2027?

Not initially. The Home Energy Model has been delayed and SAP 10.3 will initially be the approved methodology for demonstrating compliance for new dwellings.

Does Cornwall’s Policy SEC1 still apply?

Yes. SEC1 forms part of Cornwall’s planning-policy framework and sits alongside national Building Regulations. Cornwall Council advises that it should be considered early because orientation, architectural form, landscaping and materials influence energy performance.

Should a project aim beyond minimum compliance?

That is a decision for the client and design team, but there can be sound reasons to do so. Lower heat demand, carefully controlled ventilation, reduced thermal bridging, effective shading and robust detailing can support comfort, resilience and more predictable performance. The correct ambition should reflect the site, budget, programme and client’s long-term priorities.

This article provides general information and is not project-specific regulatory or legal advice. Transitional arrangements and compliance depend on the circumstances, submission route and design of each project. Confirm your position with your architect, Building Control body and a competent energy assessor.

Related Architectural Insights

• The Architecture of Comfort: SAP, U-Values and Thermal Performance
• Replacement Dwellings in Cornwall
• Passive House Principles for Low Energy Homes in Cornwall
• Low Carbon Home Design in Cornwall
• Sustainable Architecture in Cornwall