Complaints guide

Complaints guide

Complaints guide

Complaints guide

If your complaint is about an NSI Approved Company

NSI will investigate complaints regarding:

  • Non-compliance with technical standards.
  • Professional conduct.


  • As a Certification Body NSI issues Certificates of Approval to organisations who work in compliance with recognised standards.
  • Before complaining to NSI, you should complain formally in writing to the approved company.
  • You should submit to us any evidence you have that corroborates and supports your complaint. We cannot uphold a complaint unless there is sufficient supporting evidence.
  • Where material facts are disputed we may be unable to form a view in favour of either party.
  • Where we determine there is sufficient evidence to support a complaint, we will advise you the proportionate action we will take. Any action we take will depend on the nature of the complaint. In an extreme case, NSI may determine to withdraw approval from an Approved Company. In most cases NSI considers the ‘root cause analysis’ with the company concerned and instructs it to make changes to its processes in line with continual improvement / quality management principles. Where appropriate, we may take additional action, to address the complaint raised.
  • All complaints remain on record, allowing NSI to identify any emerging patterns.
  • If a legal dispute is in progress, it may be appropriate for NSI to await the outcome from the court, prior to taking further action in relation to the complaint.
  • We are not in a position to uphold a complaint of non-compliance against an approved company unless our decision would in our view be likely to “stand-up” were the approved company to make an appeal.

NSI will not investigate:

  • financial, commercial and contractual disputes
  • outstanding payments, or interpretation of NSI approved companies’ terms and conditions of contract
  • consideration of questions of a financial settlement between an NSI approved company and its customer
  • legal liability
  • discussions and negotiations regarding loss claims or potential loss claims
  • if there are any legal proceedings, civil or criminal, in process

Note: NSI will only investigate complaints regarding Approved Installers when:

  • the complainant has a maintenance contract in place and the system has a valid certificate of compliance; or
  • if the system installed is still under warranty as provided by the installer and has a valid certificate of compliance.

If your complaint is about a Company falsely claiming to hold NSI approval

If a company is masquerading as being NSI approved, NSI will:

  • Contact the company and request that any false references are removed from website/literature etc
  • If the company does not make the requested changes, NSI may place the company on the NSI Wall of Shame
  • Consider its position and other appropriate action

If your complaint is about NSI

  • You should submit your complaint below and submit any evidence you have that corroborates and supports your complaint. Where material facts are disputed we cannot uphold a complaint unless there is sufficient supporting evidence.

Note: If your concern relates to a Certification Decision, you should not make a complaint but should Appeal the decision. Please refer to the Certification Process page for a summary of the Appeals Process.


  • We will confirm receipt of all complaints within 5 working days.
  • We will advise you of any further information we require from you in order to process your complaint and outline to you our next steps.
  • When we have completed the complaint investigation, we will advise you of the outcome accordingly.

Note: In order to process a complaint, NSI may share information submitted with other parties unless instructed otherwise.

To raise a complaint please complete the complaint form