Guide to the Declaration of Conformity (DiCo) - Clemp

The Declaration of Conformity (DiCo, "Dichiarazione di Conformità" in Italian) is the document, introduced by DM 37/2008 (Italian Ministerial Decree 37/2008), with which the installation company certifies that a system has been built to industry standards, in compliance with the applicable technical safety rules (UNI, CEI) and the filed designs.

For a plumbing/heating or HVAC company it's the single most important compliance document: without a DiCo the system can't be put into service and the client can't obtain an occupancy permit, tax deductions (Ecobonus, Conto Termico) or sign supply contracts.

When it's mandatory

DM 37/2008 requires a DiCo for systems installed in residential, commercial and production buildings. The main types covered:

• Heating, air-conditioning, climate control and refrigeration systems
• Water supply and sanitary systems
• Combustible gas distribution and utilization systems
• Fire protection systems
• Electrical systems serving heating systems

The DiCo is mandatory for new installations, conversions, extensions and extraordinary maintenance. For routine maintenance alone it isn't required, but updating the system service log remains mandatory.

What the form must contain

The DiCo form (Attachment I to DM 37/2008) is structured into mandatory sections. An incomplete DiCo is the number-one cause of disputes during inspections and building procedures. The minimum content:

1. Details of the installation company (business name, registered office, VAT number, Chamber of Commerce registration)
2. Details of the qualification under DM 37/2008 (letters a-g)
3. Client details and the property's location
4. Type of work carried out
5. Description of the system
6. Technical standards applied (UNI, CEI)
7. Main components installed, with data-plate details
8. Signature and stamp of the technical manager
9. Attachments (materials report, design if required, certifications)

Penalties

Art. 15 of DM 37/2008 provides for administrative penalties against the installation company:

• From €100 to €1,000 for formal or documentation violations (incomplete DiCo, missing attachments, late delivery).
• From €1,000 to €10,000 for more serious violations, such as a missing DiCo on systems subject to a design requirement, or work not carried out to industry standards with an impact on safety.

How much it costs to prepare a DiCo

There's no official issuance fee for the DiCo. The real cost is back-office time: gathering attachments, transcribing data-plate details, checking applicable standards and preparing the form ready to be signed. On average 30-60 minutes per system. On the market, having the drafting done by a professional is typically quoted between €200 and €400 for a standard residential system.

Full in-depth guide

This article is a summary. For the detailed form, all the mandatory attachments, the connection with the F-Gas Database and EU Regulation 2024/573, and the most common mistakes when filling it in, read the full DiCo guide.

With Clemp the DiCo draft is generated automatically from the voice notes and photos the technician sends over WhatsApp at the end of the job: it arrives in the office already filled in, ready to be checked and signed.