Mechanical Ventilation with Heat Recovery, commonly known as MVHR, has become an essential feature in modern energy-efficient homes. Designed to provide continuous fresh air while retaining heat that would otherwise be lost, MVHR systems play a critical role in maintaining indoor air quality and reducing heating costs. As more properties adopt low-energy building standards, particularly those aligned with frameworks such as Passivhaus Institute, the reliance on MVHR technology continues to grow. However, like any mechanical system, MVHR units require maintenance and occasional repairs to function effectively over the long term.
MVHR systems operate by extracting stale MVHR repairs air from wet rooms such as kitchens and bathrooms while simultaneously supplying fresh, filtered air into living areas and bedrooms. The outgoing air passes through a heat exchanger, transferring warmth to the incoming fresh air without mixing the two air streams. This process significantly improves energy efficiency. When faults occur, they can compromise not only comfort levels but also energy performance and indoor air quality. Recognising early signs of malfunction is essential in preventing more serious issues.
One of the most common problems encountered in MVHR systems is reduced airflow. Homeowners may notice rooms feeling stuffy or experiencing increased condensation on windows. Reduced airflow can result from blocked filters, obstructed ductwork, or failing fans. Filters are particularly important, as they trap dust, pollen, and other airborne contaminants. Over time, clogged filters restrict airflow and force the unit to work harder, potentially leading to motor strain. In many cases, replacing filters resolves the issue, but if airflow does not improve, further inspection of internal components may be required.
Another frequent repair concern involves unusual noises coming from the unit. MVHR systems are designed to operate quietly, so rattling, humming, or grinding sounds often indicate a mechanical fault. Loose components, worn bearings, or debris caught within the fan assembly can all produce noise. If left unaddressed, these minor issues may escalate into significant mechanical failure. Professional technicians typically dismantle the affected components, clean or replace worn parts, and ensure correct alignment before reassembling the system.
Heat exchanger faults are less common but more serious. The heat exchanger core is central to the system’s efficiency, and any damage or internal blockage can reduce heat recovery performance. Symptoms may include colder supply air during winter months or higher-than-expected heating bills. In some cases, the exchanger can be removed and cleaned, particularly if dust buildup is the culprit. However, cracked or severely damaged cores often require replacement. Because the heat exchanger is integral to the unit, repairs should always be handled by qualified specialists.
Electrical faults can also affect MVHR performance. Modern systems rely on control boards, sensors, and programmable controllers to regulate airflow rates and maintain balanced ventilation. Faulty wiring, blown fuses, or sensor malfunctions can cause intermittent operation or complete system shutdown. Diagnosing electrical problems requires specialist equipment to test voltage, continuity, and sensor calibration. Prompt repair is crucial to restore balanced ventilation and prevent moisture accumulation within the property.
Preventative maintenance plays a major role in reducing the need for extensive MVHR repairs. Annual servicing by experienced engineers ensures that filters are replaced, fans are inspected, ductwork connections are secure, and airflow rates remain properly balanced. Many issues arise not from manufacturing defects but from neglect. Regular inspections help identify wear and tear before components fail entirely, extending the system’s lifespan and maintaining optimal energy efficiency.
The cost of MVHR repairs varies depending on the nature of the fault. Minor issues such as filter replacement or basic cleaning are relatively inexpensive, whereas motor or heat exchanger replacement can represent a more significant investment. Nevertheless, timely repairs often prevent greater expenses associated with damp damage, mould growth, or excessive heating bills. For homeowners committed to energy-efficient living, maintaining an MVHR system is not merely about comfort but about protecting the overall performance of the building.
In summary, MVHR repair is an important aspect of maintaining healthy, efficient homes. Whether addressing airflow reduction, mechanical noise, electrical faults, or heat exchanger damage, swift action ensures that the system continues to deliver fresh air and energy savings. As modern construction increasingly embraces high-performance standards, proper care and repair of MVHR systems remain essential for long-term sustainability and indoor comfort.