Our services

Heating replacement study

This is the core piece of work for an owner. We collect the meter readings and the building data, from a questionnaire or a site visit, then compare the options that are realistic for that particular building: an air-to-water heat pump, a ground-source heat pump on boreholes, district heating, wood, or a hybrid. Each one is set out with its capital cost, its running cost over twenty years, its CO2 and the subsidies it qualifies for, together with the permit route and a programme. The report is delivered within three weeks, and we present it to you or to your condominium meeting.

Heat pumps: sizing, noise and permit

Sizing comes first: the heat load to SIA 380/1, the heating output to SIA 384/201 and domestic hot water to SIA 385/2. SIA is the Swiss society of engineers and architects, whose standards the cantons apply. An oversized machine is the fault we correct most often, because it short-cycles, loses efficiency and makes more noise.

Noise is what actually blocks an outdoor unit. Since 1 November 2024 the determining figure has been the sound power level at 2 °C outside air, the night-time limit governs, and the assessment point is the middle of a neighbour's open window. A re-entrant corner in a façade costs about 6 dB before you start; a hood buys roughly 3 dB, night mode 5 dB and an acoustic screen 6 dB. We produce the official justification on form LN-1a and tell you whether the unit needs a permit, a notification or neither.

For eight new houses over a shared underground car park at Trélex, completed in 2026, we sized one 8 kW air-to-water heat pump per house, specified the car park ventilation with carbon monoxide and nitrogen oxide detection, and compared nine tenders. At Orbe a new house has a 12 kW reversible air-to-water unit on R290 propane, with cooling through the floor circuits.

Ventilation and indoor air

In Vaud, cantonal regulations require the energy service's authorisation above 1,000 m³/h of extract air per building, and heat recovery becomes compulsory beyond that threshold. For dwellings, SIA 382/5:2021 calls for 30 m³/h of supply air per room and at least 50 m³/h of extract air per dwelling in continuous operation; other building types follow SIA 382/1. We design both extract-only systems and balanced supply-and-extract systems with heat recovery, and we check the acoustics and the ductwork before the tender rather than after the complaint.

Energy compliance and permit applications

In the canton of Vaud a project is submitted through the mise à l'enquête, the public consultation, and CAMAC, the cantonal clearing house, circulates the file to the cantonal departments. We prepare the energy part: the SIA 380/1 calculation and the EN-VD forms, the standard cantonal energy forms. In Geneva the cantonal energy office, the OCEN, expects a building energy concept, based for an existing building on the IDC index of measured heat consumption. A major renovation, meaning works worth more than half the building's insured value, triggers full compliance of the envelope, which is why the calculation has to be done properly from the start.

Energy certificates, Minergie and subsidies

The CECB is the Swiss building energy certificate, graded A to G and known as the GEAK in the German-speaking cantons; the CECB Plus version adds a costed renovation scenario. Michael Zgraggen is an accredited CECB expert and issues both. We also belong to the Minergie association — the Swiss low-energy building label, with its stricter Minergie-P and Minergie-ECO variants — and take projects through certification.

Subsidies under the Programme Bâtiments have to be applied for before work begins, and a CECB Plus is often a precondition. One trap costs owners the entire grant: for measures up to 70 kW no fossil back-up is tolerated, so a small gas boiler kept on just in case disqualifies the heat pump.

Tenders, site supervision and turnkey appointments

We write the specifications, run the tender, compare the offers line by line, then supervise the works, witness commissioning and check the settings. The modular six-classroom school building in the canton of Geneva ran this way, with a 24.3 kW air-to-water heat pump, radiators at 40/35 °C, an 800-litre buffer vessel and BIM construction drawings.

On a turnkey appointment we take the whole sequence — permit, tenders for every trade, programme, site management, handover and the subsidy application — while you keep the decisions and the payments. There is more on our French page about the turnkey project.