The right location for a heat pump outdoor unit follows four rules: as much distance as possible from noise-sensitive neighbouring windows, no installation in reflective corners or narrow gaps between buildings, an outlet direction towards uncritical surfaces – and short pipe runs as a secondary criterion, not the first. Anyone who keeps to this order usually passes the noise protection certificate without additional measures.
Key points in brief
- Every doubling of the distance lowers the noise level by around 6 dB – distance is the cheapest noise protection measure there is.
- Walls and corners reflect sound: the same unit is measurably louder at a corner of the house than when free-standing.
- What matters is not your garden but the nearest noise-sensitive window of the neighbour – including the one upstairs.
- The shortest pipe run is the most common planning mistake: it decides metres of pipe, while the location decides decades of neighbourly peace.
- Night mode and an acoustic enclosure are add-ons – not a substitute for a good location.
Why the location matters more than the data sheet
Two identical heat pumps, two properties, two completely different results: at one location the unit passes the noise protection certificate with a comfortable margin, at the other it fails. The difference is almost never in the unit – it's in distance, reflection and direction. These three factors alone determine what arrives at the decisive point: the open window of the nearest noise-sensitive room at the neighbour's.
That's why every heat pump project with us starts with the location question – on site, not at the desk.
Rule 1: Use distance – it's free
Noise decreases sharply with distance: as a rule of thumb, every doubling of the distance is worth around 6 dB. Between four and eight metres from the neighbour's window, that's a difference that can decide whether the certificate passes or fails.
In practice, that means first finding the zone on the property that is furthest from the nearest neighbour's bedroom – often the street side or the side facing your own patio. Your own comfort is actually the best ally here: wherever you wouldn't want to hear the unit yourself, your neighbour certainly doesn't either.
Rule 2: Avoid reflections
A sound source in front of a wall seems louder than free-standing, and louder again in a corner – the sound energy is reflected into the remaining space. The classic amplifiers on single-family home properties:
- Corners of the house (two reflective surfaces at a right angle)
- Narrow passages between the house and garage or between two buildings – they act like a sound channel towards the neighbouring property
- Niches and light wells, which can additionally colour the tone of the noise
In the noise protection certificate, these situations show up as surcharges. The consequence for planning is simple: better two extra metres of pipe than a location in the sound funnel.
Rule 3: Control the outlet direction
The fan blows out in a directed stream – and the unit is heard most clearly in the outlet direction. That direction should therefore point at uncritical targets: your own garden, the street, a boundary wall with no window behind it. Not at the neighbour's bedroom, not into a narrow passage.
For some units, the outlet direction can be altered structurally (deflector hoods); it's better to choose it correctly from the start. Together with distance and avoiding reflections, that already covers most of the issue – before accessories even come into the conversation.
Rule 4: Pipe runs are the fourth criterion, not the first
The most common planning mistake we see when refurbishing other systems: the unit stands where the basement penetration was shortest. Short pipes save a few hundred francs in pipework and excavation once – a poor location, on the other hand, costs continuously: conflicts with neighbours, conditions, retrofitted acoustic walls, and in the worst case, relocating the unit.
The correct order: first determine the acoustically good zones, then look for the most economical pipe route within those zones. There is usually a solution that combines both – but the order of search decides it.
When a good location isn't enough: the additional tools
Sometimes the property is simply narrow. Then – and only then – do the add-ons come into play, sorted by effect per franc:
| Measure | Effect | Note |
|---|---|---|
| A quieter unit model | high | often a moderate surcharge, no structural work |
| Configure night mode | medium | reduces speed during critical hours – not always active from the factory |
| Acoustic enclosure/wall | medium to high | effective, but needs space, costs money and affects appearance; airflow must not suffer |
| Indoor installation | high | shifts the issue to ducts and structure-borne noise – a discipline of its own |
Classification from planning practice; the actual effect depends on the individual case and is calculated in the noise protection certificate.
A word of warning about acoustic enclosures: if sized incorrectly, they restrict the airflow, the heat pump loses efficiency and cycles more often – the noise problem becomes an efficiency problem. Such accessories should be calculated by the specialist company, not ordered from a catalogue.
The special case of structure-borne noise
Not all noise travels through the air: if the unit stands on a surface that can vibrate, or is rigidly connected to the building, vibration travels into the walls as structure-borne noise – audible as a hum in the bedroom, even when everything seems quiet outside. The countermeasures are well known and inexpensive if planned in from the start: a decoupled foundation, vibration dampers, flexible pipe connections. For indoor installation, the same applies in a more pronounced form.
At every site visit, we always ask first: "Where does the nearest neighbour sleep?" The question surprises many people – but it sorts out the location options faster than any calculation. And we know a second pattern well: systems that were signed off during the day and become a dispute at night. During the day, everyday noise masks the unit; at three in the morning with the window open, perception is different. That's why we consistently plan for the night-time case – whoever passes at night always passes.
Frequently asked questions
How far does the heat pump need to be from the neighbour?
There is no fixed minimum distance – what matters is the calculated noise level at the nearest noise-sensitive window, which must comply with the planning values. As a rule of thumb: more distance solves most problems, and every doubling brings around 6 dB.
May I place the unit directly on the property boundary?
Under building law, your municipality's boundary distances apply; acoustically, the certificate is what counts. Right on the boundary, however, the unit is usually also close to the neighbour – rarely the best idea, even if it were permitted.
Is indoor installation automatically the quieter solution?
For the neighbours, usually yes; for your own house, not automatically: air ducts and structure-borne noise need to be planned properly, otherwise you bring the noise into the building. Done well, indoor installation is a strong option – especially in narrow or protected locations.
Does a plinth or a tray help against the noise?
Little against airborne noise, a lot against structure-borne noise: a decoupled foundation with vibration dampers prevents vibrations from travelling into the building. That's part of our standard installation.
Can I change the location afterwards if problems arise?
Technically yes, but expensive – the foundation, pipework and possibly the procedure have to start over. That's exactly why care before construction pays off: the best time for the location discussion is the first site visit.
Free initial consultation
On-site location check – before planning begins.
We assess noise, pipe routes and procedures directly at your property and show you the options. Free of charge and without obligation.
Prefer to talk? +41 78 830 83 35
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Swissolar-certified specialist company · ESTI installation authorisation (Art. 14 NIV) · in Zurich since 2017 · over 150 systems completed · a personal answer from the specialist company, no call centre
Sources: LSV/enforcement practice (noise protection certificate), FWS – Swiss Heat Pump Association, manufacturer documentation, ecoEn planning practice.
Last updated: 9 July 2026 · Author: ecoEn editorial team
