Sustainability statements for a change of use

A change of use that creates no new floorspace gives a planning authority far less to work with on sustainability than a new build does. There is no new fabric to set a standard for, no site-wide energy strategy to require, and on a prior approval route there may be no power to ask about energy at all. What policy can still reach are water efficiency where an optional Building Regulations standard has been adopted locally, electric vehicle charging, cycle and waste storage, and any renewable installation you are proposing anyway. A proportionate sustainability statement says that plainly and then evidences the measures that do apply.

The commonest mistake is submitting a new build energy statement with the building type changed.

What policy can and cannot require without new build

Start with the route. A full planning application for a change of use gives the authority the development plan and its sustainability policies to apply, subject to the usual tests of relevance and reasonableness.

A prior approval under permitted development does not. The matters for prior approval are listed in the General Permitted Development Order for each class, and for the commercial to residential class they run to transport, contamination, flooding, noise, natural light and a small number of others. Energy and sustainability are not among them. An authority cannot refuse prior approval on sustainability grounds or require a statement it has no power to consider, and it is worth saying so politely in the covering letter when a validation list asks for one anyway.

On a full application, two national constraints shape what a policy can require. Planning should not duplicate Building Regulations, and the relationship between local energy standards and Part L has been contested since the written ministerial statement on housing standards in 2015, while the Planning and Energy Act 2008 continues to allow local plans to set energy requirements. Check the adopted plan and the current national position rather than assuming either way.

The practical result for a conversion is a short list of things that can properly be required and a longer list of things that cannot.

Measures that apply to an existing envelope

The measures worth putting in a statement are the ones deliverable without demolishing anything.

Thermal elements being renovated as part of the works have to meet Building Regulations standards for those elements, so the fabric improvements follow from the scope rather than from policy. Where a wall is being replastered, a floor relaid or a roof stripped, insulation to the current standard comes with it.

Controls and services are where a conversion gains most for least. Zoned heating controls, thermostatic valves, low-temperature emitters sized for a future heat pump even where a boiler goes in now, LED lighting throughout, and daylight and presence controls in common areas.

Heat pump feasibility is worth testing and documenting even where it is not being installed. Flow temperature, emitter sizing, hot water storage space and external unit position all have to work, and a conversion that leaves no plant space has foreclosed the option for the building's life. The permitted development position for the external unit is a separate question again.

Airtightness improvements in an existing envelope cost little and work well, and they create a ventilation obligation. A sealed conversion without adequate ventilation produces condensation and poor air quality, so pair any airtightness work with a ventilation strategy.

Roof-mounted solar, where the structure takes it and the orientation justifies it. Where the roof is also doing other work, biosolar roofs: energy, drainage and biodiversity together sets out how the layers interact.

Where Building Regulations take over

Drawing the line clearly is the single most useful thing a sustainability statement for a conversion can do. A table does it faster than prose.

Part S is the one most often missed on a conversion. It applies to new residential buildings and to buildings undergoing a material change of use to create dwellings, and it requires charge point provision where dwellings have associated parking, subject to a cost exemption per charge point. Deal with it in the statement and on the drawings, because a late discovery at building control stage can mean rerouting a supply through a finished building.

Part O overheating is treated differently from Part L for changes of use, and the position is worth confirming with the building control body rather than assumed. Where the conversion produces single-aspect units with large south-facing glazing, an overheating risk assessment is a sensible thing to have even where no regulation forces it.

Water efficiency and waste in a conversion

Water is the clearest example of planning and Building Regulations working together rather than overlapping.

Part G sets a standard of 125 litres per person per day for new dwellings, including those created by a material change of use, and an optional tighter requirement of 110 litres is available where a planning authority has justified it through the local plan on water stress evidence. Planning cannot impose the tighter figure without that policy basis, and where the policy exists the mechanism is a condition requiring compliance with the optional requirement.

Meeting 110 litres in a conversion is a fittings exercise rather than a design one. Low-flow taps and showers, dual-flush cisterns and a water-efficient appliance specification get you there in most layouts, and the calculation is done with the published water calculator.

Waste is a planning matter and it is where conversions most often fail at validation. An upper-floor conversion with no bin store, no route to the kerb and no space for recycling containers gets a refuse objection that no amount of sustainability narrative answers. Show the store, its capacity, the carry distance and the collection point on the drawings.

Energy performance certificates and their relevance

An energy performance certificate is a useful piece of evidence and a poor planning condition.

As evidence it tells the officer where the building starts. Including the existing certificate, with the recommendations page, shows what is realistic and is better than any assertion about the building's performance.

As a condition it is weak. The rating depends on assumptions and a standard assessment method rather than on measured performance, it is produced after the works by an assessor outside the applicant's control, and it duplicates a separate regime. An authority asking for a condition requiring a particular band should be pointed to that duplication.

The letting regime is separate again and matters commercially rather than in planning terms. Minimum energy efficiency standards apply to privately rented domestic and non-domestic property, successive governments have consulted on raising the domestic threshold, and the current requirement and date should be checked rather than taken from an older summary. For a landlord converting a building to let, that regime usually drives the fabric specification more than planning policy does.

Writing a proportionate statement

Eight to twelve pages is plenty for a conversion, and a shorter document that answers the policies is worth more than a long one that does not.

1. A policy schedule listing every sustainability policy in the development plan, with a line on each saying how the proposal responds or why the policy does not apply to a change of use.
2. A description of the existing building: age, construction, current use, existing certificate, existing services.
3. The scope of works, because it determines which Building Regulations duties are triggered.
4. The measures proposed, each with a reason.
5. The measures considered and set aside, with the reason, which is the section officers read most closely. Structural capacity, heritage constraints, tenure and plant space are all legitimate reasons where they are evidenced.
6. The regulatory interface table.
7. Water, waste, cycle parking and charge point provision, cross-referenced to the drawings.
8. The conditions you are offering.

That last point does real work. Offering a condition is faster than negotiating one. A Sustainability Statement that proposes its own conditions tends to be approved on the terms it proposes.

Conditions that are reasonable at this scale

Four are reasonable on a conversion, and a handful are not.

Reasonable ones: compliance with the optional water efficiency requirement where local policy supports it, details and implementation of cycle and refuse storage before first occupation, details of any renewable installation with a requirement that it be installed before occupation, and a lighting specification where external lighting is proposed.

Harder to justify: a condition requiring a particular energy performance certificate band, a formal environmental assessment rating on a small conversion where the scheme and the fee are both designed for larger projects, post-occupancy monitoring and reporting, and a carbon reduction percentage measured against a notional baseline the existing building never had. An Energy Statement built around a percentage improvement on a new build target does not translate to a building with no new floorspace, which is why the two documents should not be confused.

Where a condition is proposed that duplicates Building Regulations, say which Approved Document covers it and offer the alternative.

Enter your postcode on PlanScope to see which reports a conversion is likely to need.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.