Energy statements for flats and apartment blocks are a different exercise from the same document for a pair of semis. The carbon calculations run per dwelling but the decisions — heating plant, roof space, riser routes, metering — are made per block. Get the block-level strategy wrong and every one of your SAP calculations inherits the problem. This guide covers what an energy statement needs to show for apartment schemes in 2026, and where flats genuinely differ from houses.
If you are new to the document itself, start with what an energy statement is and when you need one; this post assumes the basics and focuses on multi-dwelling buildings.
Do flats need an energy statement?
Whenever the local planning authority requires one — which for apartment schemes is usually yes. Most councils trigger the requirement for major development (10+ dwellings), which almost every block meets, and many require an energy statement for any new dwelling. In London, all applications referable under the London Plan need a full energy assessment following the GLA's energy assessment guidance, and boroughs apply the same energy hierarchy to smaller schemes through local policy.
How the calculations work for a block
The statement starts from a Part L 2021 baseline: each flat gets its own SAP 10.2 calculation against its notional dwelling, and the results are aggregated to report a whole-scheme carbon position. That aggregation is where blocks behave differently from houses:
- Flats start with less heat loss. A mid-floor flat has neighbours above, below and beside it, so its fabric performance per square metre is inherently better than a detached house — but its top-floor and corner units drag the average, so the weakest flats, not the typical one, set your risk.
- The site-wide percentage is what planners read. Carbon reduction targets — including London's 35% on-site target — are assessed across the development, letting strong units compensate for constrained ones.
- Shared systems enter every SAP. With communal heating, the plant efficiency and distribution losses appear in every dwelling's calculation, which is why heat network design dominates block results.
Heating: the decision that shapes the whole statement
For apartment blocks the heating strategy is the energy statement's centre of gravity, and in 2026 the realistic options are:
- Individual heat pumps per flat — increasingly common for small and mid-rise blocks; needs external unit locations (balconies, roof) resolved early, or monobloc/exhaust-air units where space is tight.
- Communal ambient or low-temperature heat network served by central heat pumps — the default for larger London schemes; heat interface units (HIUs) in each flat, with distribution losses minimised by design.
- Connection to an existing or planned district heat network — where one exists nearby, policy usually expects connection or future-proofing; heat network zoning under the Energy Act 2023 will make this expectation firmer as zones are designated.
Gas boilers — individual or communal — are now hard to justify: SAP 10.2's electricity emission factor (0.136 kgCO₂/kWh, versus 0.210 for gas) means electric heat pumps beat gas on carbon comfortably, and from 24 March 2027 the Future Homes Standard removes fossil fuel heating from new homes altogether. The carbon arithmetic is set out in our post on heat pumps vs gas boilers in energy statements.
Solar PV when the roof is shared
Houses can usually find roof space for PV; blocks cannot always. A ten-storey building has one roof serving dozens of flats, and that roof also hosts plant, ventilation and amenity space. The energy statement should therefore:
- show a realistic PV layout — panel area, orientation and output, not a token allowance;
- decide how PV is used — landlord supply (lifts, corridor lighting) is simplest; supplying flats individually needs metering arrangements resolved;
- evidence any shortfall honestly. The Future Homes Standard's new Requirement L3 expects on-site renewable generation on new homes — with provisions recognising that tall buildings with small roofs relative to floor area cannot match houses, which is exactly the situation your statement must document. Our guide to sizing solar PV for an energy statement covers the calculations.
London blocks: the 35% target and the offset
For London schemes, the energy statement must work through the full energy hierarchy — Be Lean (fabric), Be Clean (heat networks), Be Green (renewables) — and demonstrate at least a 35% on-site carbon reduction beyond Part L 2021 under London Plan Policy SI2. Apartment blocks generally reach it through the communal heat pump route plus rooftop PV. Any residual shortfall to zero carbon is settled through a carbon offset payment to the borough — budget for it early, because on a large block it is a real number. See our guides to carbon offset payments and the offset calculator to estimate exposure.
Part L 2021 now, Future Homes Standard from 2027
Energy statements for blocks submitted today are assessed against Approved Document L (Part L 2021). The Future Homes Standard — published 24 March 2026, applying to building regulations applications from 24 March 2027 — will make heat pumps and on-site renewables the regulatory baseline, cutting new-home emissions by around 75–80% against 2013 standards. For schemes with long build-out programmes, say in the statement which regime each phase will be built under; the transition rules are covered in our transitional arrangements guide.
Key takeaways
- Apartment energy statements are judged site-wide, but weak units (top-floor, north-facing) set the design risk.
- The heating strategy — individual heat pumps, communal heat pump network, or district connection — dominates the carbon result; gas is effectively finished for new blocks.
- Roof-limited PV must be evidenced with a realistic layout, not a token figure.
- London blocks need the full hierarchy, 35% on-site, and a costed carbon offset for the residual.
How Fortress Associates can help
Our energy statement service produces a planning-ready statement from a Part L 2021 / SAP 10.2 baseline, working through the full Be Lean, Be Clean, Be Green hierarchy with CO₂ savings calculated at each stage — including London Plan SI2 35% compliance and carbon offset figures for London schemes. The report is free, ready in minutes, uses site-specific solar and energy data, and covers every UK local authority. For fees, see the energy statement cost guide, or contact us about your scheme.
Sources & further reading
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