DIY MVHR Maintenance vs. Professional Servicing: When is it time to call the professionals?

DIY vs Professional MVHR Servicing: What can you do - and what should be left to the professionals?

Mechanical Ventilation with Heat Recovery (MVHR) systems work around the clock to keep your home fresh, healthy, and energy efficient. But just like any home system, it needs ongoing care. Think System, not just unit .  The MVHR unit you see is connected to a series of ducts and air valves that work together to deliver fresh air to the home and remove stale air full of humidity and odours, so its more than just the filters to keep it working effecrively!

So, let’s explore what maintenance you can handle—and when it’s time to call in the professionals.

DIY Maintenance Tasks - for occupants

1.    Filter checks & replacements (every 3–6 months)

Two filters inside the unit help protect the motors and your indoor air quality.  Clogged MVHR filters, just like your hoover,  reduce airflow, strain your system, and lower indoor air quality. It is recommended to check MVHR Filters every  3-6 months and where necessary replace them e.g. if they are thick with black muck and debris — filters in urban or pet-heavy homes may clog faster. 

2.    Outdoor vent inspections 

Visual checks of the external intake and exhaust vent grilles is a good idea (if you can see them - more difficult on high rise apartments) to check they are free from leaves or debris—all of which can significantly hinder your system’s performance.

3.    Wipe away dust and dirt that collect around grilles and valves 

Build-up in these areas can restrict airflow, making ventilation systems less efficient and potentially leading to overheating or poor circulation. Regular cleaning also helps prevent allergens and pollutants from being recirculated throughout the home, supporting a healthier living environment.

4.    Listen for unusual noises or error codes

Strange buzzing, rattling, or persistent error messages suggest internal faults. If basic troubleshooting doesn’t fix it, professional diagnostics are essential 

When to Call in the Professionals

1.    Deep internals cleaning & inspection

Only professional servicing can properly clean the heat exchanger, inspect motors, measure airflow, and assess condensate lines. These checks are crucial for longevity and efficiency 

2.    Diagnosing complex faults or replacement parts

Issues like failed PCBs, motor wear, or heat exchanger damage require specialist tools and technical know-how to identify and resolve 

3.    Annual testing & airflow balancing

Professionals perform annual testing to ensure your unit runs at optimal efficiency, including checking fan outputs, duct integrity, and balancing airflows 

4.    Warranty compliance and system robustness

Manufacturer warranties often require professional servicing. Plus, only qualified technicians can safely test and service components without voiding coverage.

Why you need a professional 

There are several reasons why you need a professional service including the risk of:

Decline in Air Quality: One of the first signs that your MVHR system might need professional maintenance is a noticeable decline in air quality. If your home starts to feel stuffy, the steam from the shower isn’t clearing or odours linger, vents might be the culprit. There may also be something wrong with system components like the PCB or motors.

Unusual Noises coming from the MVHR unit: Another indicator is unusual noises coming from the MVHR unit. Sounds like rattling, loud humming, or buzzing could point to debris inside the system, issues with the fan motor or incorrect set up of trickle and boost speeds.

Condensation and Mould issues: The appearance of condensation on windows or mould in certain areas of your home is a significant warning sign. This suggests that the MVHR system isn’t moving air effectively.

Unit not boosting: If the boost function isn’t working and the unit is running on a single speed meaning it can't be controlled, a PCB inside the unit may have failed causing it to need replacing - sometimes lights on the system indicate the fault.

Error Codes: Keep an eye on the system’s control panel. If you notice error messages or frequent resets, these could be parts or software issues that require prompt attention.

For more information on signs you need a professional check out our blog on Top 5 Signs Your MVHR System Needs Maintenance 

What to expect during a MVHR service appointment 

• Acomprehensive service targets the key parts of the system that need attention
• Cleaning and sanitising the inside of the MVHR unit and its motors
• heat exchanger is cleaned and sanitised
• Filters are then replaced as part of the service

For more information on what to expect check out our blog on What to Expect During a MVHR Service Appointment 

You can also find information on your MVHR and MEV repairs in your product manual, these can be found here on our website!

What happens if you don’t service your MVHR system?

Overall neglecting regular servicing can lead to reduced airflow, increased energy bills, and even costly breakdowns. Over time, dust, debris, and clogged filters strain your system, compromising indoor air quality and overall performance.

Let HRV Group take care of it

Our experienced engineers specialise in all makes and models of MVHR systems across Greater London. Whether you need a one-off service or regular maintenance, we're here to help.

Book an MVHR Service here 

Need filters? Visit The Air Shop

We stock replacement filters for all brands—delivered straight to your door. Keep your system running efficiently with the right filters at the right time.

View The Air Shop Filters here

Get a ventilation service quote