The Argile sizing API exposes the calculation engine over REST in JSON, with a response time under 200 ms and endpoints for heat pumps, photovoltaics, insulation and domestic hot water. It takes site survey data as input, areas, volumes, walls, joinery, existing systems and climate data at the address, and returns outputs and thermal resistances computed on the same rules at every call. What matters for the firm is not the speed but the repeatability: the same survey always gives the same result, which makes the output adopted defensible under inspection. The assumptions stay in the firm's hands, the API does not correct a wrong survey, it carries it through to the quote.
What is a sizing API for on your retrofit job sites in 2026?
Going from the site survey to a reliable calculation without wasting time
A sizing API links your surveys (surfaces, volumes, photos, plans, climate zones) to a calculation engine. The result: you get a reliable calculation without re-entering data, with clear assumptions that are exportable for the job file and the grants.
Reducing power and equipment choice errors (heat pump, ventilation, insulation)
Correct sizing means avoiding a heat pump that is too big and short-cycles, or too small and struggles on cold days. An API can apply rules derived from reference frameworks, check the consistency of heat loss, and secure the right power rating. The same logic applies to ventilation (flow rates) and insulation (thermal resistances), with alerts when a choice falls outside the norms.
Responding faster to requests with consistent, comparable scenarios
With an API, you generate several scenarios on an identical basis. You compare options (insulation first, then heat pump, or the reverse) and you send a quote faster. The client sees clear variants, you keep control, and your recommendation stays consistent with the fabric-first order PAS 2035 expects.
What data should you plan for to automate your sizing calculations?
Building data: surfaces, volumes, walls, joinery, orientation, use
To automate a reliable sizing, start from a solid base. Enter the heated surfaces, volumes and ceiling heights, then the walls (walls, floors, roofs) with their materials and insulation. Add the joinery with glazing type, dimensions, airtightness, orientation and shading. Finish with the intended use, the temperature setpoints and the room zoning.
Technical data: existing systems, emitters, networks, installation constraints
List the existing system and its settings: generator, power rating, flow temperatures, regulation, DHW, ventilation. On the distribution side, specify radiators, underfloor heating, indoor units, as well as the state of the networks (lengths, diameters, heating network balancing). Also note the constraints: available space, access, noise, condensate drainage, flue system, and electrical capacity.
External data: local weather, altitude, regulatory context, address-based Open Data
Calculations gain in accuracy with local weather and a design external temperature, altitude, wind exposure, and microclimate. Integrate the scheme and installation rules (TrustMark, PAS 2030:2023, MCS) and, via an API, pre-fill using address-based open data: the EPC register, mapping and land registry data, flood risk zones, conservation area and listed building constraints, networks.
How the Argile API automates the sizing of your projects
Fast energy diagnosis and retrofit scenarios in under 5 minutes
With the Argile API, you start from a fast energy diagnosis. In 5 minutes, the platform estimates the heat loss, proposes scenarios (insulation, ventilation, heating) and gives orders of magnitude for the power rating and the surfaces to be treated. You keep control of the assumptions, without getting lost in spreadsheets. Once the project firms up, the sizing report compliant with NF EN 12831-1 comes out of the workflow with no extra work.
Feasibility analysis: technical constraints automatically detected at the address
Starting from an address, the feasibility analysis cross-references public data: at the address, climate zone, altitude, building type, access or planning constraints, presence of a gas network. The system highlights what often blocks a sizing, then suggests realistic alternatives.
3D reconstruction and technical visit assistance to make calculation inputs more reliable
3D reconstruction and technical visit assistance secure your surveys. Reliable measurements, openings, heights, surfaces, insulation thicknesses, heat pump unit locations. Once the inputs are made reliable, your calculations and quotes gain in precision, without extending the time on site, in line with the workflow from technical visit to quote.
From calculation to quote: integrating automation into your pricing and the grants
Pre-costing and detailed quotes: linking sizing, quantities and prices
With a tool connected to your price libraries, the sizing (heat pump, insulation, ventilation) automatically feeds the quantities. Surfaces, lengths, power ratings, accessories, everything flows through into the pre-costing, then into a detailed quote. An API can also push these lines to your ERP or your invoicing software, without re-entering data.
Funding calculation: ECO4 and the Boiler Upgrade Scheme directly in the quoting journey
In the same journey, you work out what the chosen scenario can attract, according to the measure, the target performance and your certifications. In 2026, the client mainly wants a simple answer: the remaining cost, any advance payment and the documents to prepare. Automation reduces oversights and secures your funding.
Standardising your deliverables: assumptions, results, supporting documents and traceability
Standardise your assumptions (surface, thermal resistance, COP, regulation), your results and the expected supporting documents. With templates, you produce a quote, a calculation note and a consistent, timestamped evidence file. This traceability makes checking easier and speeds up exchanges with the grant bodies.
Best practices for deploying an API in a renovation company
Defining your internal rules: assumptions, margins, options, quality checks
Before opening your API to your quoting or grant tools, set clear rules. List your assumptions (surfaces, resistances, efficiencies), your margins per work package, your standard options. Add simple quality checks. For example, alert thresholds on heat pump power ratings, consistency of insulation U-values, missing administrative documents.
Securing exchanges: access management, confidentiality, calculation responsibility
Apply the principle of minimal access. One token per application, role-based rights, and regular key rotation. Encrypt exchanges (HTTPS), log calls, and define what falls under your responsibility. Housing data, client data, grant calculations. Also plan a "read-only" mode for partners.
Measuring field impact: quoting lead times, signature rate, share of comprehensive retrofits
Track field indicators every week. Average quoting time, number of quotes sent, signature rate, and share of comprehensive retrofit projects. Link these figures to API changes. A useful improvement shows up quickly in your schedule and your order book.
