Mechanical Ventilation with Heat Recovery, or MVHR, has become a cornerstone of modern energy-efficient homes, providing both ventilation and heat retention. By continuously exchanging stale indoor air with filtered fresh air while recovering heat, these systems help maintain indoor air quality and reduce energy consumption. MVHR units are often installed in airtight homes, loft spaces, or utility areas, and brands such as Zehnder, Vent-Axia, and Nuaire have built strong reputations for reliable performance. However, despite their durability, MVHR systems can encounter operational issues over time, necessitating repairs to maintain efficiency and comfort.
One of the first signs of an MVHR problem is usually a noticeable drop in airflow or uneven ventilation in different rooms. This often stems from clogged or dirty filters, which can restrict air movement and place extra strain on the fans. Filters trap dust, pollen, and other airborne particles, and if left uncleaned, they can reduce the system’s heat recovery efficiency. In more severe cases, a neglected filter can lead to contamination of the heat exchanger, requiring professional cleaning or even replacement to restore optimal performance.
Fan problems are another common reason for MVHR repairs. The fans operate continuously to maintain airflow, and this constant use can lead to worn bearings, motor failures, or electrical faults. Homeowners may notice unusual noises such as rattling, humming, or high-pitched whines originating from the unit. Ignoring these sounds can result in more serious damage, including complete fan failure. Qualified ventilation engineers can inspect, repair, or replace faulty fan components to ensure the system runs smoothly and quietly.
Heat exchanger issues can also arise, particularly in older systems or units that have not received regular servicing. The heat exchanger transfers warmth from outgoing stale air to incoming fresh air, and any damage, blockage, or frost formation can significantly reduce efficiency. In colder climates, frost protection may fail, allowing ice to form inside the exchanger, which restricts airflow and may trigger safety shutdowns. Repairing or replacing the heat exchanger often requires specialist knowledge to ensure airtight seals and correct airflow distribution throughout the home.
Electrical and control system faults are increasingly common with modern MVHR units. Many units now include digital controllers, humidity sensors, and programmable settings to optimize operation. Electrical failures, software glitches, or sensor malfunctions can cause the system to operate continuously at high speed or fail to respond to humidity levels, reducing comfort and efficiency. Diagnosis and repair involve checking circuit boards, recalibrating sensors, and sometimes replacing control modules to restore proper functionality.
Ductwork can also be a source of problems requiring repair. Leaks, disconnected sections, or crushed ducts reduce airflow and efficiency, while poor insulation can result in condensation, mould growth, or water damage. Repairing ductwork often involves resealing joints, improving insulation, and rebalancing airflow throughout the property to maintain consistent ventilation.
Regular servicing and early intervention are essential in preventing small issues from escalating into costly repairs. Professional MVHR engineers typically perform a comprehensive inspection, including filter checks, fan assessments, heat exchanger evaluation, and electrical system tests. Routine maintenance ensures that the system continues to MVHR repairs operate efficiently, maintains energy savings, and preserves indoor air quality.
In conclusion, MVHR systems are vital for modern airtight homes, combining ventilation with energy conservation. Timely repairs, regular servicing, and attention to components such as filters, fans, heat exchangers, and ductwork are crucial for sustaining performance. Homeowners who invest in professional maintenance enjoy not only the full benefits of energy-efficient ventilation but also improved comfort, healthier air quality, and long-term protection of their property.