Your MVHR system has been fitted. Now you need to ensure it’s doing the best possible job, which you do by commissioning the system. So what is MVHR commissioning all about?

Fitting MVHR is only half the battle

You can probably have an MVHR system installed easily enough. But like any mechanical system it can be fitted badly or properly. You want it to perform brilliantly? It’s all about professional commissioning, tinkering with the system until it does exactly what it says on the tin and works to the very best of its ability. It is a requirement of Building Regulations that an MVHR system is not only designed properly but, more importantly, is proved to be working the way it was designed to work.

What does commissioning an MVHR system involve?

Commissioning combines fan speed adjustment on the MVHR unit with altering the flow rate through the air valves. When you get the combination right, you get the best possible level of airflow, with the least noise and the greatest efficiency.

How do you measure it? It’s done using a piece of kit called an anemometer, which is used to test and adjust each valve and adjust the MVHR unit itself, according to the system’s design and specification. It’s important to use the right kind of gadget, a special hooded anemometer which must be calibrated every year at a UKAS-accredited calibration centre.

As a general rule, if the system’s fan is set too high things can get noisy. In an ideal world the unit itself will be set to run as slowly as possible to reduce noise, cut vibration and exchange the right amount of air over the desired timescale. The lower the running speed, the more energy efficient, cost effective and long-lasting the system will be.

Once the right rates of airflow have been set, the valves are locked in position and the airflow rates recorded for Building Control. There’s a special form and inspection checklist designed for the purpose, which can be found at the back of the Domestic Ventilation Compliance Guide.

The measurement test sheet has three elements:

1. In Part 1 The details of the system are recorded including the installation address and the installer’s details
2. Part 2a is an installation checklist and 2b records the outcome of the visual inspection
3. Part 3 is where the results of the mandatory air flow test are recorded, AKA MVHR system commissioning – the bit you hand to Building Control

MVHR commissioning – What happens when you get it wrong?

Get it wrong and your system won’t be compliant. This means you won’t conform with Building Regulations, which can have horrible financial consequences, especially if your build isn’t finished on time as a result.

Common problems arising from sub-standard installation of the ducting and units include excessive noise, low airflow rates and trapped moisture in the ducts, which leads to unit damage, ceiling damager, poor air quality and even health-threatening mould. All of which means it makes a lot of sense to get your installation commissioned by an expert.

We have taken the relevant qualification and passed with flying colours. Which means you can trust us to commission your MVHR system correctly.