Frequently asked questions.

After your request, an I.ON advisor gets back to you and you receive a quote within 7 days. For projects requiring a technical visit (heat pump, complex renovation), the detailed quote is prepared after the on-site visit.

I.ON operates throughout Western Switzerland, notably in the cantons of Vaud, Geneva, Fribourg and Neuchâtel. Our team is based in Rolle, in the canton of Vaud.

I.ON Energy Services Sàrl is a Swiss company based in Rolle, in the canton of Vaud. We design and install solar systems, heat pumps, battery storage, EV chargers and air conditioning, and issue EPC (CECB/GEAK) certificates. The study, installation and follow-up are handled by our in-house team.

Yes. The study of your project (roof or heating analysis, sizing, grant estimate) is free of charge and without obligation. You can request it via the contact form or directly online with our configurator.

Yes. Grant applications (Pronovo, cantonal and municipal schemes), notifications to the grid operator and permits: I.ON handles all administrative steps related to your project.

For a single-family home, the installation typically takes 2 to 4 days. The roof remains functional throughout the work and the home's electrical supply is only cut for a few hours during the final grid connection.

The panels we install (Jinko, AIKO, LONGi, Arres Solar) are guaranteed for 25 years at 80 % of their initial output. Their effective lifespan generally exceeds 30 years with annual degradation below 0.5 %.

The payback period averages 7 to 10 years for a well-sized residential installation, taking into account cantonal grants and the federal one-time payment. Beyond that, production remains essentially free until end of panel life.

You can combine the federal one-time payment (approximately 350 to 450 CHF/kWp depending on size), variable cantonal grants (Vaud, Geneva, Fribourg, Neuchâtel) and tax deductions on the investment. I.ON handles all administrative steps.

A battery increases your self-consumption from 30 % to 80 % depending on sizing. The return on investment for a battery is longer (12 to 15 years) but it provides partial independence in the event of a grid outage. We assess each case individually.

Any drop in production is detected by our 24/7 monitoring and addressed by our in-house team within 48 hours. Fronius, SMA and SolarEdge inverters benefit from manufacturer warranties of 10 to 25 years.

A heat pump captures thermal energy from the air, ground or water and concentrates it to heat your home. To produce 100 % of the heat you need, it only consumes 25 to 35 % in electricity; the remaining 65 to 75 % come free from the environment.

The seasonal COP (SCOP) varies by type: 3.5 to 4.5 for air-to-water, 4.5 to 5.5 for vertical geothermal. We contractually guarantee the seasonal COP calculated during the study.

Budget 32,000 to 48,000 CHF gross for a well-sized air-to-water unit, 55,000 to 80,000 CHF for geothermal. Cantonal grants amount to 4,000 to 9,000 CHF depending on the canton and output. With tax deductions, the effective net cost falls to 21,000–32,000 CHF for a standard air-to-water unit.

Yes. Modern air-to-water heat pumps (Daikin Altherma 4 H, Vaillant aroTHERM plus, Stiebel Eltron WPL-A, Panasonic Aquarea T-CAP, Alpha Innotec hybrox, Buderus Logatherm WLW176i) operate down to -20 °C with a reduced COP. Geothermal is never affected by outdoor temperature since it draws from the stable-temperature ground. No electric backup is required for correctly sized installations.

An air-to-water heat pump is installed in 2 to 4 days on site. Geothermal requires 5 to 10 days, mainly for borehole drilling. The existing heating remains operational until the final switchover.

Not necessarily. Many oil heating systems from the 1980s and 1990s are originally oversized, which allows the heat pump to operate at 50 °C flow temperature without changing the radiators. When some radiators are undersized, we replace 2–3 targeted units rather than the entire system.

On a house consuming 3,000 litres of oil per year (approximately 3,900 CHF/year), an air-to-water heat pump reduces the heating bill to 1,700–2,400 CHF in electricity. A saving of 60 to 70 %. Over 20 years, cumulative savings exceed 30,000–60,000 CHF, comfortably covering the switch to a heat pump.

It is neutralised and removed. This is included in serious quotes, at 1,500 to 3,500 CHF depending on volume and accessibility. The freed space becomes a utility room, workshop or storage. Underground tanks may require more extensive work.

Strongly recommended. A boiler that fails in the middle of winter puts the owner in an emergency position: no time to compare quotes, no time to put together the grant application, and often the oil has to be reconnected temporarily. Planning 6 to 12 months ahead changes everything.

A battery storage system installed by I.ON starts at CHF 6,500 for 10 kWh (BYD Battery-Box). A Huawei Luna 2000 or a Fronius Reserva of equivalent capacity ranges from CHF 7,000 to CHF 9,000, installation included. The price depends on capacity, brand and compatibility with your existing inverter.

Without a battery, a household self-consumes about 30% of its solar production. With a battery, that figure rises to 70–80%. For an 8 kWp installation in Western Switzerland, the extra saving is CHF 600 to 900 per year. The payback period of a battery is 8 to 12 years depending on your supplier's electricity rate.

For a 4–5 room house consuming 4,000 to 5,500 kWh per year, a 10 kWh battery is recommended. It covers evening and night consumption. For a house with a heat pump or an EV charger, scale up to 13–15 kWh. I.ON sizes the battery based on your actual consumption curve (12-month meter reading).

Yes, in most cases. If your inverter is compatible (Fronius, SolarEdge, Sungrow, Huawei, KOSTAL), the battery connects directly on the DC or AC side depending on the topology. Otherwise, a partial inverter replacement may be required. I.ON assesses compatibility during the free study and proposes the most cost-effective solution.

The LFP (Lithium Iron Phosphate) batteries installed by I.ON have a lifespan of 12 to 15 years, or 6,000 to 10,000 cycles. The manufacturer warranty covers 10 years with a minimum residual capacity of 60 to 70%. Beyond that, the battery keeps running with reduced capacity, with no safety risk.

Only if the installation includes the backup function (Fronius Reserva by default, Huawei and BYD optional with a dedicated module). Without backup, the battery is disconnected from the grid for safety reasons during an outage. With backup, you retain 5 to 15 kW of autonomy on prioritised circuits.

The EPC certificate (CECB in French, GEAK in German) assesses the energy efficiency of a building's envelope and the amount of energy it consumes under standard use. It rates the building from A (very efficient) to G (very inefficient) on two scales: envelope and overall energy.

The standard EPC provides the energy label and general recommendations. The EPC Plus adds a comprehensive advisory report with a three-variant action plan, cost and return-on-investment estimates, and detailed calculation of available grants. The EPC Plus is generally required to access significant grants.

The EPC is mandatory to obtain most cantonal grants related to energy renovation (roof, façade, windows, heating). It also helps compare different renovation variants and avoid low-impact investments.

It depends on the canton. Vaud has required an EPC since 2025 for buildings constructed before 1990. Geneva, Fribourg and Neuchâtel have partially similar rules. Valais and Jura do not require an EPC on sale in 2026 but strongly recommend it.

The on-site visit by an accredited expert takes 1 to 2 hours for a single-family house, 2 to 4 hours for a building. The expert records the envelope characteristics (insulation, windows, roof, slab) and collects energy bills. The report is delivered within 3 to 4 weeks.

An EPC remains valid for 10 years, provided no major modification affects the building's heating needs. For grants, an EPC of less than 24 months is often required, which may mean an update is needed.

Yes, exactly. CECB is the French name, GEAK the German name of the same certification. The report produced is identical in structure and methodology. The language of the report can be adapted on request.

Yes, and increasingly so. On the 2026 market, the price gap between an F–G rating and a C–D rating reaches 10 to 18 %. A good B or A rating justifies a market premium. Presenting the EPC Plus report with the action plan already implemented is a strong selling argument.

Only EPC experts accredited by the national umbrella association (the Conference of Cantonal Energy Directors). I.ON is registered as an accredited EPC expert for Western Switzerland. The official list is available online by canton.

An 11 kW charger (three-phase 16 A) covers 95 % of residential needs: it charges an electric car from 0 to 100 % in 6 to 8 hours, i.e. one full night. A 22 kW charger halves this time but requires a 32 A three-phase installation and approval from the grid operator.

Budget 1,800 to 3,500 CHF all-in for an 11 kW residential charger (equipment, installation, connection, configuration). For a 22 kW charger or a multi-charger site, the quote depends on the electrical upgrades required and can range from 2,400 to 5,500 CHF depending on complexity.

We install a smart meter that measures your solar production in real time and controls the charging. The car can be charged solely on your solar surplus, or in mixed mode (solar priority with grid top-up to finish the charge). All fully configurable.

OCPP (Open Charge Point Protocol) is the open standard for charger management. It allows your charger to be supervised by any compatible platform, without depending on the manufacturer. For multi-charger sites and fleets, we install OCPP-compatible chargers.

A notification to the grid operator (Romande Energie, SIG, Groupe E) is mandatory before installation, to verify that the connection can support the output. No building permit is required for a residential charger installed indoors or against the façade.

Yes, with the landlord's written agreement. The charger generally remains the property of the tenant, who can remove it on departure. Connection costs and associated consumption are the tenant's responsibility.

Yes. We install multi-charger sites (up to 30 charge points) with dynamic power management to avoid electricity subscription overruns. OCPP supervision allows centralised settings and billing.

It depends on your mileage. A car consuming 18 kWh/100 km and covering 15,000 km/year uses 2,700 kWh/year, approximately 750 CHF/year at standard electricity rates. With charging mainly on solar surplus, the cost can fall to 200–300 CHF/year.

We install five brands: Fronius (Wattpilot Flex), SolarEdge, GoodWe, Huawei (Smart Charger) and Easee (Charge Core). The simplest choice is the brand of your inverter: the charger follows your solar production and everything is set in the same app. Easee works with any installation, with or without solar panels. Each model is available wall-mounted or on a freestanding pedestal.

A reversible air conditioning unit (or air-to-air heat pump) reverses its cycle to cool in summer and heat in the shoulder seasons. It effectively replaces a direct electric heater while providing excellent summer comfort. The heating efficiency (COP) remains above 4 in the majority of cases.

For a single-zone wall-mounted split (one room), budget between 3,500 and 5,500 CHF all-in. For a multi-zone system (3 to 5 rooms), between 9,000 and 14,500 CHF depending on brand and technology. The quote is prepared after a technical visit.

In Western Switzerland, installing an outdoor unit may require a declaration or permit depending on the municipality and co-ownership. I.ON handles all administrative steps. For buildings in co-ownership (PPE), the approval of the owners' assembly is generally required before installation.

The Daikin, Mitsubishi and Panasonic units we install have a typical lifespan of 12 to 20 years with regular maintenance. The manufacturer warranty is 5 years, extended to 10 years on certain premium references.

Modern models (class A+++ or SEER ≥ 8) consume three to five times less than an old unit. Coupled to your solar installation, summer consumption can be almost entirely covered by your solar production, at the moment it is highest.

Modern Daikin, Mitsubishi, Panasonic units produce 40 to 50 dB(A) at 1 metre, equivalent to a library. With careful placement (at least 3 metres from neighbouring windows, appropriate orientation), Swiss noise protection (OPB) standards are met without difficulty in residential areas.

Technically yes, but it is rarely the right choice in the Swiss climate. The COP drops in severe cold and air distribution from a split is less uniform than underfloor heating. For primary heating, an air-to-water heat pump remains preferable. Reversible air conditioning is ideal as a supplement or for shoulder seasons.

Recommended to preserve the warranty and performance. Budget 200 to 350 CHF/year for a single-split, 350 to 600 CHF for a multi-zone. Maintenance includes filter cleaning, refrigerant pressure check and electrical connection inspection.

Units installed since 2024 use R32, whose global warming potential is three times lower than the previous R410A. Future European regulations will push towards R290 (propane) with very low impact, already available on certain premium references.