WarmtepompGeluid
Evening+Night
54
Day
59
dB(A) max LwA

Property

Residential zoning

Outdoor unit

Zb = 1.15 m · Q = 2 · On: Schuur

Margin

3 dB

Sound power

Buildings

Garden walls

Left
Right

Receiver positions

No receiver positions. Click '+ Receiver position' on the map to add one.

Buitenunit staat op hoogte - controleer ook ramen/deuren van buurwoningen! Voeg ontvangposities toe op de hoogte van nabijgelegen ramen.

Result

Evening+Night
54
dB(A) max LwA
Day
59
dB(A) max LwA
Qbron = 2 · Margin = 3 dB
Max Lp at boundary: 40 dB(A)
(at LwA = 57)
Side cross-section
Side cross-section — Shows the height of buildings and the sight line from the outdoor unit to the loudest point on the property boundary. There is a clear line of sight between the outdoor unit and the measurement point.

Calculate heat pump noise: unit on the garden shed

The shed at the back of the garden seems a logical spot for the outdoor unit: nice and far from your own bedroom. But what is good for your own sleep is not automatically good for the neighbours’. At the rear of the plot three boundaries often meet — left, right and rear — and a 3-metre shed roof lifts the unit above every fence.

In this preset the unit starts on a 3-metre shed close to the rear boundary. Drag the unit and the shed around to find which combination works.

How to use the tool for this situation

  1. 1
    Position the shed

    Adjust the shed’s position and dimensions under “Buildings”. Is yours in the corner? Then the unit sits close to two boundaries at once.

  2. 2
    Drag the unit across the roof

    Small moves matter here: going from the corner to the middle of the roof often gains several dB on both side boundaries.

  3. 3
    Check all boundaries

    Under “Residential zoning”, tick every side bordering a neighbour’s garden — at the rear that is usually three. The critical point (red marker) moves along.

  4. 4
    Consider alternatives

    Compare with the “In the garden” preset (unit at ground level next to the shed): on the ground the unit benefits from screening by fences and by the shed itself.

The back of the garden: closer to the neighbours than you think

A typical terraced-house garden is 5 to 8 metres wide. A shed in the corner puts the unit within 1–2 metres of two boundaries. At that distance geometric attenuation is minimal: the sound arrives almost unweakened. By comparison, the same unit in the middle of a 6-metre shed roof easily gains 4 to 6 dB over the corner position.

Height makes it worse. At 3.8 metres (roof plus base) the unit looks over virtually every fence, removing the screening a ground-level unit would enjoy. And since rear gardens are where people sit outside and sleep with windows open, complaints there carry weight in practice.

Shed roof or ground level?

It is worth calculating both. One storey lower, on the ground next to or behind the shed, the unit benefits from screening by the shed itself and by fences. On the other hand, a ground-level unit may be closer to one specific boundary, and a corner between shed wall and fence gives an unfavourable directivity factor (Q=0.5: +6 dB versus free field).

Practical rule of thumb: the smaller the garden, the more often ground level with a good screen beats the shed roof. In large gardens where the shed is far from all boundaries, the roof can be fine. The map above shows it per situation.

How does the calculation work?

The calculator is based on WPAC-geluid V2020, the official Dutch calculation tool for noise from outdoor heat pump and air-conditioning units, developed for the Ministry of the Interior. It computes the sound transmission loss (D) from the outdoor unit to each assessment point: the larger the transmission loss, the more sound power the unit is allowed to produce.

Distance is the dominant factor: every doubling of distance reduces the level by 6 dB. The directivity factor Q also matters — a unit within 2.5 metres of one wall (Q=1) is 3 dB louder than a free-standing unit (Q=2), and a corner between two walls (Q=0.5) adds another 3 dB. Reflections from building walls raise the level, while buildings between the unit and the assessment point screen the sound.

The transmission loss yields the maximum allowable sound power (LwA) of the unit: max LwA = limit + D − margin. The safety margin (default 3 dB, minimum 2 dB) covers design and measurement uncertainty. Compare the calculated maximum with the sound power on the unit’s energy label or product documentation.

The noise limits in brief

Since 1 January 2024 the noise requirements for heat pumps and air conditioners are set by the Besluit bouwwerken leefomgeving (Bbl), the successor to the Dutch Building Decree 2012. Article 4.107(2) Bbl states that an outdoor heat or cold generation installation may cause at most 40 dB at the boundary with a neighbouring residential plot. For situations on the same plot — such as apartment buildings — the same limit applies at openable windows and doors of another dwelling (article 4.108(3) Bbl).

The 40 dB limit applies in the evening and at night (19:00–07:00). If the unit has a low-noise setting (silent mode) active during that period, a limit of 45 dB applies during the day (07:00–19:00). Without silent mode the unit must meet 40 dB during the day as well. Read more on the heat pump noise limits page.

Frequently asked questions about this situation

Is the back of the garden quieter for the neighbours than next to the house?

Not necessarily. Three boundaries are often nearby at the rear, and neighbours experience the noise exactly where they sit outside or sleep. A position closer to your own house, with screening, can be better on balance. Calculate both.

Does the shed itself count as a noise screen?

Yes — for a ground-level unit the shed can block the sight line to part of the boundary and provide several dB of screening. The tool calculates this automatically for every building you draw. With the unit on top of the shed, only the roof edge provides limited screening.

My shed stands against the neighbours’ fence. What does that mean?

Then a unit on the shed roof stands practically on the boundary and distance attenuation is near zero. Meeting 40 dB is then only feasible with a very quiet unit, an enclosure, or another location.

Do I need receiver positions at windows here too?

Yes — as soon as the unit is higher than 2.5 metres (almost always on a shed roof), the tool advises checking upper-floor windows of surrounding homes as extra receiver positions.

Calculate other situations

In the garden On extension On the roof Apartment

Further reading

This calculator provides an indicative result based on WPAC-geluid V2020 and does not replace a formal acoustic study. When in doubt, consult an acoustic consultant or your municipality.