Ventilation System Commissioning

Our service

Ventilation systems such as Continuous Mechanical Extract Ventilation (CMEV/DMEV) and Mechanical Ventilation with Heat Recovery (MVHR) systems require commissioning by a competent person for you to satisfy Regulation 42 under Approved Document F of the Building Regulations.

Elmhurst enegry approved ventilation scheme member logo

We follow a best practice process and air flow measurement, Method A – The Unconditional Method using a UKAS certified measuring instrument. This is done to ensure your ventilation system is functioning as intended and performing in line with the intended design.

Ecotest will also provide you with a handover at the completion of the commissioning process, so you understand exactly how the system is performing and how it is to be operated by the end user

Our approach

We recognise that each ventilation system is unique and aim to keep things simple for our clients.

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Contact us about your ventilation system


If you have had a ventilation system installed in your project such as a CMEV, DMEV or MVHR, you should have had that system professionally designed. This may have been done by your Architect, M&E Consultant, Ventilation Manufacturer or an Independent Ventilation Design Consultant.

Approved Document F of the Building Regulations sets out the requirements for ventilation systems and therefore your system should have been designed to be compliant. However, without the system being commissioned it may not be operating as intended in the design. Your CMEV, DMEV or MVHR system can be inspected, tested, commissioned and certified by us to verify that the designed performance is achieved.

Ecotest want to assist you with your commissioning requirements, so please get in touch and we will take you through the commissioning process.

Defining your requirements


We need to understand the type of Ventilation system, whether you have a design, air flow rate calculations and where the terminals are located.

Continuous Mechanical Extract Ventilation (MEV)

Fans which run continuously and window slot vents. Extract terminals service all wet rooms. You may know them as Centralised Mechanical Extract Ventilation: CMEVs and Decentralised Mechanical Extract Ventilation DMEVs.


Mechanical Ventilation with Heat Recovery (MVHR)

No window slot vents and terminals service all wet and habitable rooms.

Once we understand your ventilation system and its design, we can tailor our service to meet your requirements, which may include air flow rate calculations.

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We’ll prepare a clearly defined quotation


Our quote will clearly define our service offering, requirements on site and terms and conditions. We will provide the quote to you in writing for your approval.

Attending site to carry out our survey and commissioning services


With your agreement, we will attend site to carry out our commissioning service. When we have not been involved in the design or installation of a ventilation system, we first need to complete a survey to understand whether or not it is commissionable.

Once we are certain we can commission the system we will follow the procedure approved by the manufacturer. We will make the necessary adjustments to the system to meet the design and record the relevant information. We use specialised UKAS calibrated equipment, known as a Zero Pressure Flow Meter (Method A – The Unconditional Measurement Method).

However, if the ventilation system is not commissionable, Ecotest uses its expertise and knowledge of ventilation system design and installation to advise you on what we believe to be the best course of action.

Consultant using the DIFF Automatic Air Volume Flow Meter to commission a mechanical ventilation with heat recovery (mvhr) unit
Nissen hut mechanical ventilation with heat recovery (mvhr) supply and extract terminals to an open plan kitchen and living area

We provide relevant handover information and certification following our commissioning process

Commissioning Report

Following our site visit we will provide you with our ventilation report. This document will include all the relevant information from the commissioning process. This will allow you to demonstrate compliance to your Build Control Body against the design, Approved Document F and Regulation 42 of the Building Regulations. The ventilation manufacturer may also require this to activate any applicable warranties.

Why is comissioning my ventilation system important?

Commissioning your ventilation system is important to ensure your building is appropriately ventilated. The benefits of commissioning ventilation systems include:

1. Improved Indoor Air Quality

Commissioning helps to ensure that the system is installed correctly, which improves indoor air quality and reduces the risk of indoor air pollution.

2. Energy Efficiency

Commissioning ensures that the system is functioning correctly, which helps to reduce energy consumption and maximise heat recovery (if applicable).

3. Compliance with the Building Regulations and Manufacturer’s warranty:

Commissioning helps to ensure that the system meets the requirements of the building regulations and manufacturer’s requirements for warranty policies, reducing the risks of an uncompliant or unwarranted system.

4. Improved System Performance

Commissioning helps to identify any potential issues with the system, which can be addressed before they become more serious.

5. Peace of Mind

After your investment you want to secure the benefits of your ventilation system. By commissioning the system you are provided with assurance that the system is functioning correctly.

However, there are also additional consequences that can result from a ventilation system that has not been commissioned:

1. Increased moisture

Potential for increased moisture and humidity levels, which can result in condensation and structural damage.

2. Poor indoor air quality

Potential for build up of indoor air pollutants and a lack of fresh air can also result in stagnant air, which can lead to poor indoor air quality, increased levels of allergens and stuffy or unpleasant odours.

3. Energy waste

Potential for increased energy use if fan motors are running excessively.

4. Building damage

Potential for structural damage as moisture can cause rot, rust, corrosion which can all degrade the building’s fabric.

Ecotest believes it is important the building owners should ensure their ventilation systems are commissioned to best mitigate these consequences.

Get in touch to learn more

We will support you to find the best ventilation and air tightness strategies for your project.

Frequently asked questions

What is background ventilation?2023-03-02T09:50:58+00:00

A small ventilation opening designed to provide controllable whole building ventilation (e.g. window slot vents a.k.a trickle vents).

Do I need background ventilation?2023-03-02T10:12:52+00:00

That depends on your ventilation system:

Q: Intermittent extract fans

A: Yes you do, please refer to Part F of the Building Regulations or contact us for more support.


Q: Continuous mechanical extract ventilation

A:  Generally yes, but it depends on the air permeability of your building, contact us for more support.



A: No you do not require background ventilation methods, such as window slot vents.

What is continuous mechanical extract ventilation?2023-03-02T10:38:49+00:00

A ventilation system that compromises of either a central ducted continuously running extract fan (centralised a.k.a CMEV), or a set of local continuously running extract fans in the wet rooms (de-centralised a.k.a DMEV), or a combination of both. Fresh air is supplied into the habitable rooms via background ventilators where applicable.

What is Mechanical Ventilation with Heat Recovery (MVHR)?2023-03-02T10:40:19+00:00

A mechanical ventilation system that compromises of a centrally ducted unit with supply and extract fans. Air is extracted and passed through a heat exchanger, to fresh air from outside which is supplied and is also passed through the heat exchanger to recover the heat from the extracted air. MVHR is the most energy efficient method of mechanical ventilation within dwellings, as the building’s heat is recovered, opposed to other methods which extract only that expel the heat.

Do MVHRs require any ongoing maintenance?2023-03-02T10:39:53+00:00


MVHR systems have filters on both the supply and extract side. The filters require checking regularly, cleaning and replacing. Once you know how your filters are performing you can assess how often they need to be cleaned or replaced. We recommend checking your filters after 1 month, then every 3 months for the first year. This will allow you to build a maintenance schedule tailored to your MVHR and how the filters are performing. This is generally a simple process, however Ecotest would be happy to set up an ongoing filter change maintenance plan for your MVHR system.

There are also other aspects to an MVHR system that require less frequent maintenance (such as cleaning) and in these instances you should always follow the manufacturer’s guidance.

If you have any questions or require support please contact us.

Ecotest clearly explained the benefits of having DMEVs in my property and the requirements for them to be commissioned. They were very responsive and their service was professional. I would definitely recommend Ecotest and will use them again if required.

Jane Nicholson, Self-Build Client

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