Understanding first-step in 2026: what the first_step_v2 criteria are for when building a renovation scenario
What we mean by a "scenario": objectives, energy gains and constraints of the home
A scenario is a coherent trajectory of work. You set a performance, comfort and budget target, then choose the trades in the right order. The aim is measurable gains (kWh, euros, CO2), without overlooking the home's real constraints. For example: insulation, airtightness, ventilation, then heating. Otherwise, you risk shifting the problem instead of solving it.
The essential information to collect on site to make your scenario reliable
On site, a few well-taken measurements are worth more than a spreadsheet filled in at random. For a reliable scenario, secure the basics.
- Surface areas and orientations (roof, walls, floors, windows).
- Condition and makeup of the walls, existing insulation, visible thermal bridges.
- Heating, domestic hot water, controls, emitters, output, age, maintenance.
- Ventilation, air inlets, wet rooms, signs of moisture.
- Site constraints. Access, services, drainage, outdoor unit location.
What changes in practice with first_step_v2: watch points to avoid inconsistencies
first_step_v2 is used to frame the criteria that trigger or block choices. The idea is to spot inconsistencies early. An insulated surface that doesn't match the measurements, a heat pump proposed without checking the emitters, improved airtightness without suitable ventilation. In 2026, this rigour helps produce a scenario that's administratively solid for the funding schemes, and avoids backtracking at the quote stage. To limit rejections, you can also rely on a guide to avoiding rejected applications.
first_step_v2 criteria: the parameters that (really) change a scenario
Envelope: insulation, airtightness, thermal bridges, the impact on your scenario
On the envelope, a scenario changes as soon as you touch the thermal resistance of the walls. Loft, walls, ground floor. The more you reduce heat loss, the more the heating output drops. Airtightness limits infiltration, but it must go hand in hand with properly managed ventilation. Poorly treated thermal bridges push needs back up and can create condensation.
Systems: heating, domestic hot water, ventilation, weighing performance, cost and ease of installation
On systems, the scenario depends on the generator/emitter pairing. A well-sized heat pump, with controls, can cut the bill, but requires a consistent hydraulic network or suitable indoor units. For domestic hot water, a heat-pump water heater or solar system changes the budget and footprint. Mechanical ventilation, single- or dual-flow, weighs up air quality, gains and installation complexity.
Constraints and feasibility: surface area, ceiling height, access, electrical supply, exposure, EPC
Finally, feasibility sorts out the blocking points. Surface area available for insulation, ceiling height, loft access, space for the outdoor unit. Check the incoming supply rating and the duct routing. The site's exposure and the EPC band guide sizing and priorities. A robust scenario respects these constraints, otherwise it stays on paper.
Building a coherent renovation scenario: a field method for registered tradespeople
Starting from priorities: addressing heat loss before sizing the system
On site, start by identifying where heat escapes. Loft, walls, floors, air leaks. A coherent scenario addresses this heat loss first with insulation, airtightness and thermal bridges. Only then do you resize heating and hot water. You avoid an oversized heat pump that's more expensive and less efficient: to go further, rely on the heat-loss method.
Thinking in variants: "essential," "comfort," "whole-house renovation" scenarios
Offer 3 clear variants. "Essential" with loft insulation and adjustments, plus minimal ventilation. "Comfort" with wall insulation, windows, high-performance mechanical ventilation and controls. "Whole-house retrofit" with envelope, ventilation and system (heat pump, boiler, solar) and possible phasing. For each scenario, give the budget, the funding and the order of work.
Avoiding common mistakes: oversizing, forgotten ventilation, material incompatibilities
Classic traps. Oversizing comes from a calculation done before insulation. Forgotten ventilation creates humidity and mould after airtightness improves. Material incompatibilities, such as a poorly placed vapour barrier or unsuitable insulation in an older building, can trap moisture in the walls. Validate the interfaces, the applicable standards and the emitter balancing.
From site visit to quote: turning your scenario into a signable proposal (with funding)
Clear pricing: trades, options, phasing and evidence for the client
After the visit, turn your scenario into a readable quote. Break it down into distinct trades (insulation, ventilation, heating), add 1 or 2 options, and specify the phasing when work items depend on each other. Attach simple evidence. Photos, measurements, technical data sheets, markers on the plan. The client understands what they're buying and why.
Factoring in the funding at the right time: impact on what the client pays
Calculate the funding before signing and, above all, before starting work. The schemes in practice require a file with compliant documents (quote, proof of registration, references). Show clearly what is left to pay, line item by line item, and plan a financing option if upfront cash flow is a barrier. To go further, rely on a practical guide to the funding schemes.
Presenting the results: expected gains, summer/winter comfort, and a commitment on performance
Present the gains as ranges. Savings, targeted energy label, and winter comfort. For summer, explain what you're acting on. Insulation, solar protection, ventilation. Frame the commitment with measured assumptions (usage, settings, maintenance), rather than an unsustainable promise.
How Argile helps you produce reliable scenarios with first-step, without wasting time
Diagnosis in under 5 minutes: quickly comparing several renovation scenarios
With first-step, you go from an address to a clear scenario in a few clicks. Argile estimates the baseline condition, proposes several combinations of work (insulation, ventilation, heating) and helps you compare the energy gains, without a spreadsheet or calculations to redo. The sorting happens upstream, when the most relevant measures are proposed from the home's characteristics and the client's objectives.
Feasibility analysis: automatically spotting the technical constraints at the address
Argile cross-references open data with your site-visit information to flag the points that can derail a scenario. Building footprint, existing system, space for a heat pump, condensate drainage, condominium constraints. You prioritise what's achievable, before making promises.
Preliminary quote and final quote: generating pricing with funding calculated in, and securing the paperwork
You turn the chosen scenario into a preliminary quote, then a final quote. Argile includes the calculation of the funding according to current rules, and lists the key documents (proof of registration, measure specifications, certificates). The result: coherent pricing and a file that's easier to get approved. On the client's side, what is left to pay and the monthly instalments appear in the costing before signature.
