Mechanical Ventilation with Heat Recovery, commonly known as MVHR, has become a central feature in modern energy-efficient homes. Designed to provide continuous fresh air while retaining heat that would otherwise be lost, these systems are particularly common in airtight properties built to high environmental standards. Brands such as Vent-Axia, Zehnder, and Nuaire manufacture widely installed units across the UK and Europe. While MVHR systems are built for durability and long service life, they are not immune to faults, wear, or performance issues. Understanding MVHR repairs is essential for homeowners and property managers who want to maintain indoor air quality and energy efficiency.

An MVHR system works by extracting stale air from kitchens and bathrooms while supplying filtered fresh air to living spaces and bedrooms. Inside the unit, a heat exchanger transfers warmth from outgoing air to incoming air without mixing the two air streams. Because these systems run continuously, components such as fans, filters, motors, sensors, and control boards are subject to ongoing mechanical and electrical stress. Over time, issues can develop that reduce airflow, create unusual noise, or compromise heat recovery efficiency.

One of the most common reasons for MVHR repair visits is poor airflow. This can be caused by blocked or saturated filters, which should typically be replaced every six to twelve months depending on usage and environmental conditions. When filters become clogged, fans must work harder, which can eventually lead to motor strain or failure. In some cases, reduced airflow may also be linked to damaged ductwork, disconnected joints, or obstructions within the ventilation system. Diagnosing the root cause requires careful inspection of both the unit and the distribution network.

Another frequent repair issue involves excessive noise. MVHR systems are designed to operate quietly, so noticeable humming, rattling, or vibration often indicates a problem. Worn fan bearings, imbalanced impellers, or loose mounting brackets can all create unwanted sound. In certain installations, noise may result from poorly secured ductwork or inadequate acoustic insulation rather than the unit itself. A qualified technician will typically assess whether components need tightening, realignment, or replacement.

Electrical and control faults also represent a significant portion of MVHR repair cases. Modern units include digital controllers, humidity sensors, frost protection systems, and sometimes smart home integration. Power surges, wiring issues, or component degradation can cause the system to stop operating or behave erratically. A unit that fails to boost when humidity rises in a bathroom, for example, may require sensor recalibration or replacement. In other cases, a faulty printed circuit board may need specialist repair or full replacement.

Condensation and drainage problems can further complicate MVHR performance. Because warm extracted air cools as it passes through the heat exchanger, condensation forms and must be drained away correctly. If the condensate pipe becomes blocked or improperly installed, water can accumulate inside the unit, potentially causing corrosion or electrical damage. Repairing this type of issue often MVHR repairs involves clearing blockages, correcting pipe gradients, and checking seals to prevent leaks.

Professional MVHR repairs should always be carried out by engineers familiar with ventilation systems rather than general heating contractors. Accurate airflow balancing and commissioning are critical to system performance. After replacing parts or resolving faults, the technician should measure supply and extract rates to ensure the system meets design specifications. Without proper rebalancing, even a successfully repaired unit may fail to deliver optimal ventilation or heat recovery.

Preventative maintenance plays a major role in reducing the need for costly repairs. Regular filter changes, annual servicing, and periodic inspection of ductwork can identify minor issues before they escalate. Many problems associated with MVHR systems stem from neglected maintenance rather than inherent defects. By keeping the system clean and correctly adjusted, homeowners can extend equipment lifespan and maintain healthy indoor air conditions.

Ultimately, MVHR repairs are about protecting both comfort and energy performance. When functioning correctly, these systems provide continuous fresh air with minimal heat loss, contributing to lower energy bills and improved wellbeing. Prompt attention to faults, combined with routine servicing, ensures that an MVHR system continues to perform as intended for many years.