Provided you’ve had your MVHR system designed, fitted and commissioned properly, it’ll deliver years and years of excellent service. But like all mechanical systems it should be properly maintained. Here’s how to troubleshoot a few of the most common issues and keep yours in good nick.

The first thing to say is this: the vast majority of feedback from MVHR users is extremely positive. On the rare occasions things go wrong it’s invariably down to poor design, installation or commissioning, not the fault of the technology or the system itself.

Help, my MVHR system is making too much noise

The most common complaints are usually about noise, something that can happen when the MVHR unit isn’t big or powerful enough for the building, a fault of the designers and something that highlights the importance of always using a professional to design, fit and commission the unit.

Annoying levels of noise can occur because of a too-small external air intake/extract terminal, too much ductwork system resistance, the wrong room air supply and extract valves/grilles or a combination of all four. If the MVHR unit is connected to small roof tile vents without enough of a free area, it can also create excessive air resistance and extra noise. These can all be put right – but it can be an expensive business.

Draughts… brr!

Some people get slight draughts directly under their supply air valves or grilles. There will always be air movement, so it can’t be resolved completely, but using the right kind of valve/grilles minimises the issue and makes draughts more or less unnoticeable.

What if you find there’s inadequate ventilation, or even too much? If the supply and extract valves aren’t placed correctly the airflow and circulation can be affected. If you move them, things should improve substantially. But proper airflow balancing by an expert in the first place helps prevent such problems.

How do water leaks affect MVHR?

Occasionally people find water leaking from MVHR units and air valves/grilles, which collects in the loft ducts. This can be because the condensate drain attached to the MVHR unit hasn’t been installed properly, or there isn’t one, full stop. If water coming through valves/grilles is collecting in your ducts it’s almost certainly because the person who fitted your system hasn’t used the recommended insulated ductwork.

How to void problems? Get it fitted by a pro

The number of MVHR systems installed has boomed in recent years and shows no sign of slowing. Properly fitted by a professional they make an amazing difference to your heating and cooling bills as well as improving your quality of life dramatically.

Problems are almost always down to bad MVHR system choices, poor design, installation, commissioning, bad communication or a lack of maintenance. All of which can be solved after the fact with varying degrees of expense… but let’s face it, it’s best to get a proper job done in the first place!