The understanding behind the calculations.
CCW Surveys is an energy and sustainability consultancy in Datchet, Berkshire. We produce planning energy statements, SAP calculations for new builds and extensions, and heat loss calculations. All three draw on the same background: thermal imaging, PAS 2035 retrofit coordination and hands-on building industry experience. We understand the calculations underneath the software. Policy and regulation are checked against the version in force, every time.
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In the Royal Borough of Windsor and Maidenhead, every new dwelling needs a Sustainability and Energy Statement with its planning application, assessed against the Sustainability SPD adopted in July 2024. What the statement has to prove is set by each council's adopted policy rather than a national standard, and the trigger and the targets vary by authority across the Home Counties and the Greater London boroughs. We write these for RBWM, the wider Home Counties and Greater London, to the live policy for each authority.
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A new dwelling needs SAP calculations to show it meets Part L of the Building Regulations, and the same calculation produces the new-build EPC. Abbas Naji is our Elmhurst-accredited On Construction Domestic Energy Assessor (OCDEA), registration BH51-0001, and produces both the Design Stage SAP and the As Built assessment with its BREL report on completion. Heavily glazed extensions can need one too. As compliance standards have tightened, consulting an OCDEA early in the design stage has become more relevant to getting a design through first time.
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The design heat loss figure is the foundation of the whole system, so inaccuracies carry through to every decision made downstream. We produce room-by-room calculations to BS EN 12831-1:2017, the method MCS requires under MIS 3005-D, desk-based from drawings or existing-property data. The whole-dwelling total sizes the heat pump; the per-room figures size the emitters at your chosen flow temperature, set out in an emitter schedule. MCS 035 performance estimate and MCS 020 a) sound calculation can also be added for a full MCS pack. With no installer relationship and no equipment to sell, what we produce answers to the property, not a product range or a sale.
The three services share one foundation: knowing the methods underneath the software, the policy structure they answer to, and the building science that explains both. That depth is what the work is built on. In practice, that means fewer surprises when a design goes back for changes, and lower costs from getting the specification right the first time.
The calculations, not just the tool. SAP, the GLA spreadsheet and a heat loss calculation each run on formulas with assumptions built in. Understanding those assumptions, and where the building in front of you departs from them, is what lets a calculation be built on evidence rather than left on defaults. It is also what finds the efficient route to compliance: a specification that meets the target while staying within what the project actually requires.
The structure behind the policy. Reduce demand, supply it efficiently, then generate renewably: the energy hierarchy is the sequence a sound assessment follows in order, whatever target an authority sets against it. In London and RBWM the GLA form of it is mandatory; across the wider South East the same sequence sits under policies that measure compliance differently. Working from the structure rather than one authority's wording keeps each step in the right order, and it is where the balance is found between what the policy asks for and what the project can carry.
The science under the regulation. An MSc in Sustainable Natural Resources covered building physics, the built environment, and the science that underpins the direction of UK policy. That grounding is why the work reads where regulation is heading, not only the version in force.
Behind all three is over 1,000 heat loss calculations and hands-on experience across the building industry, from thermal imaging and fabric diagnostics to retrofit coordination, and across a range of clients: large and complex residential properties, housing association projects at scale, and heritage buildings on a royal estate in Windsor.
We deliver SAP calculations and heat loss calculations nationally, desk-based, and write energy statements for RBWM and the Home Counties, our core area, plus the Greater London boroughs. We also work as a named sub-consultant to architects and consultancies who need capacity on any of these three services, behind their own client relationship