For thirty years, operational noise from wind turbines in the UK has been assessed principally under ETSU-R-97, the guidance first published in 1996. On 19 June 2026 the Department for Energy Security and Net Zero (DESNZ) published replacement guidance — Assessment and rating of noise from wind turbines: guidance — following a technical review and a consultation on proposed updates.
The Government states that the new guidance should be used by developers of onshore wind planning applications and by planning authorities across the UK when assessing wind turbine noise. It is the first fundamental update to the national approach in three decades, and it matters for anyone considering a commercial wind project — including the small turbines the proposed Oak Tree Rule would cover.
Why this matters for commercial small wind
Noise is one of the principal planning considerations for any wind turbine, and it is especially important where commercial or industrial sites sit close to homes. A well-sited turbine on an industrial estate can be a straightforward neighbour; a poorly sited one can stall a planning application for months.
It is not possible to judge acoustic suitability from turbine capacity alone. Rated power tells you almost nothing about how a turbine will sound at a specific receptor. What matters is a combination of factors: distance to nearby dwellings and other noise-sensitive receptors, the existing background noise environment, the turbine's sound power characteristics at the wind speeds the site actually experiences, local wind conditions, the cumulative effect of other turbines or developments in the area, and the site context.
Neither legislation nor the new guidance prescribes a single universal minimum separation distance. Each site is assessed on its own facts — which is precisely why screening noise risk early is so valuable.
What has changed
The 2026 guidance replaces the 1996 ETSU-R-97 framework with an updated assessment methodology. In plain English, it updates how developers and planning authorities should predict, measure and control operational wind turbine noise. The principal areas covered include:
Assessment methodology — a refreshed technical approach for predicting noise levels and deriving site-specific limits, replacing the 1996 method.
Operational noise limits — how limits are set for individual developments, including how they relate to the background sound environment rather than fixed one-size-fits-all numbers.
Background noise measurements — updated requirements for measuring the existing acoustic environment, including how surveys should be carried out and at which wind speeds.
Daytime and night-time considerations — separate treatment of day and night periods, reflecting the different sensitivity of receptors at night.
Tonal characteristics — how tonal noise (a whine or hum at a particular frequency) should be identified and accounted for.
Amplitude modulation — updated treatment of the rhythmic 'swish' turbines can produce, and when it requires specific assessment.
Cumulative impacts — how noise from multiple turbines, or from a new turbine added to existing developments nearby, should be combined and assessed.
Financially involved receptors — specific treatment for dwellings whose occupants have a financial interest in the development, where a different approach has long applied.
Operational monitoring — how compliance with approved noise limits should be verified once a turbine is operating.
Planning conditions — model condition wording and monitoring protocols to attach to consents, so limits remain enforceable after commissioning.
One detail worth flagging for commercial projects: for single or smaller-scale turbines — the category most on-site commercial wind projects fall into — the guidance allows a simplified total noise assessment criterion of 35 dB (up to a wind speed of 10 m/s) to be applied without measuring background sound levels, where the site circumstances are appropriate. That is a materially simpler evidence path than a full background survey, but it is a starting point for discussion with an acoustic consultant, not a licence to skip the assessment.
The practical consequence is that the guidance changes the evidence base planning authorities will expect, which affects how much acoustic work a credible application needs. For most commercial projects this is a scoping exercise rather than a barrier — and the earlier it is done, the cheaper it is.
What does this mean for the proposed Oak Tree Rule?
Separately, the Government is considering a new Permitted Development right for a single onshore wind turbine on eligible non-domestic sites — the proposed Oak Tree Rule. The consultation on those proposals closed on 10 June 2026, and the final Permitted Development criteria have not yet been confirmed.
It is important not to conflate the two. The new noise guidance is published and in effect for the assessment of wind turbine noise. The Oak Tree Rule, by contrast, remains a proposal: the Government's response and the legislation that would implement it are still awaited.
DESNZ has not formally confirmed that the new noise guidance will determine the noise requirements within the final Oak Tree Rule provisions. What the publication does provide, in the meantime, is a clear and contemporary framework for understanding and managing operational wind noise — the same framework developers and planning authorities will use while the final provisions are awaited.
Oak Tree Rule is monitoring the Government's final response and will update its guidance as soon as the final Permitted Development criteria are confirmed.
Noise should be screened at feasibility stage
The single most important commercial message from the new guidance is timing: acoustic risk should be assessed before significant money is committed. Too often, noise becomes a problem at the planning stage, after turbine selection, DNO applications, LiDAR or anemometry campaigns, structural and foundation design, and procurement have all been paid for.
Our approach is a staged feasibility assessment that puts acoustic screening early in the sequence:
Stage 1 — Desktop feasibility. Review site boundaries, surrounding receptors, planning constraints, indicative wind resource, electricity demand and potential turbine locations.
Stage 2 — Acoustic risk screening. Identify nearby noise-sensitive receptors and assess whether noise is likely to represent a material constraint on the site.
Stage 3 — Detailed feasibility. Where the site remains viable, progress turbine selection, yield modelling, grid assessment and any specialist acoustic work required.
Stage 4 — Planning or Permitted Development. Prepare the evidence required under the planning route applicable at that time.
The objective is to identify unsuitable sites early — not to sell equipment. A site screened out at Stage 2 has cost the owner a modest fee rather than a six-figure capital commitment.
What should property owners do now?
If you are considering a small commercial wind turbine, this checklist will put you ahead of most applicants:
1. Identify potential turbine locations on the site, considering existing buildings, roads, services and security.
2. Identify nearby residential properties and other noise-sensitive receptors — not just the nearest one.
3. Establish approximate separation distances from each receptor to the likely turbine position.
4. Understand the existing background noise environment around the site, including at night.
5. Obtain credible acoustic data for any turbine model you are considering — published sound power levels at representative wind speeds, not marketing figures.
6. Consider cumulative impacts where other turbines or developments exist nearby.
7. Integrate noise screening into the overall wind feasibility workstream, alongside wind resource and grid.
8. Do not purchase equipment based solely on rated kW or headline wind speed. Neither tells you how the turbine will behave acoustically on your site.
The Oak Tree Rule position
Oak Tree Rule provides independent feasibility and project consultancy for commercial wind — we are not a turbine supplier.
We don't sell turbines. Our job is to determine whether a turbine makes technical, planning and commercial sense for your site before you commit significant capital.
You can read more about the proposed initiative, our sustainable planning service for consenting strategy, and our energy audit service for understanding how a turbine would interact with your site's overall energy use. For a fuller view of site selection, see our article on site suitability for small wind turbines.
If you would like an independent view on your site, get in touch or use our free online wind feasibility checker.
The bottom line
The updated noise guidance should not be viewed simply as another planning obstacle. It replaces a thirty-year-old framework with one that reflects how turbines and the planning system actually operate today. For well-selected sites, early acoustic assessment reduces uncertainty, shortens the consenting timetable and helps developers identify viable turbine positions before significant design expenditure is incurred.
This article provides general guidance and does not constitute site-specific acoustic or planning advice. Requirements depend on turbine characteristics, site conditions, receptors and the applicable planning route.
Source: DESNZ — Assessment and rating of noise from wind turbines: guidance, 19 June 2026