Winter brings in chilly temperatures, damp weather, and a need for warm, comfortable homes. An MVHR (Mechanical Ventilation with Heat Recovery) system can be a lifesaver during these months, ensuring a steady supply of fresh, warm air while reducing energy costs. However, like any system, your MVHR needs a little preparation to perform optimally during winter.
This blog covers why winter maintenance is essential, potential issues that can arise, and actionable steps to keep your MVHR system running smoothly throughout the colder months.
Why Winter Maintenance Is Crucial for MVHR Systems
Increased Demand
Winter sees your MVHR system working harder. With windows closed and heating on, it becomes the primary source of ventilation and fresh air in your home.
Preventing Condensation Issues
Cold weather increases the risk of condensation in your ductwork, which can lead to water pooling or dripping and even damage ceilings or walls if not addressed.
Ensuring Energy Efficiency
A well-maintained MVHR system ensures that heat recovery operates efficiently, keeping your energy bills in check during the colder months.
Common Winter Issues for MVHR Systems
Winter presents unique challenges for MVHR (Mechanical Ventilation with Heat Recovery) systems, primarily due to colder temperatures and increased heating and ventilation demands. Recognising these issues can help ensure your system continues to perform optimally.
1. Condensation in Ducts
Condensation in ducts is a frequent winter issue when cold external air meets the warm, moist air inside the home. If the ducts are not adequately insulated, this moisture can condense on the interior surfaces, leading to water pooling in the ducts or dripping through ceilings. Over time, this damp environment may also encourage mould and mildew growth, potentially harming indoor air quality.
2. Reduced Efficiency Due to Dirty Filters
Filters play a vital role in trapping dust, pollen, and airborne particles. However, during winter, when the system runs more frequently, filters can clog faster. This reduces airflow, causes the system to work harder, and may lead to uneven ventilation.
3. Frost Build-Up on the Heat Exchanger
Frost can form on the heat exchanger during extremely cold conditions. This obstructs airflow and reduces heat recovery efficiency. In severe cases, the system may even shut down to protect the unit.
4. Increased Noise Levels
Cold air can cause ducts to contract slightly, leading to creaks or rattling noises. While this isn’t necessarily harmful, it can indicate loose duct connections or imbalanced airflow, which may need attention.
5. Imbalanced Airflow
Adjustments to ventilation settings in winter, such as reducing extraction rates to retain warmth, can lead to imbalanced airflow between supply and extract ducts. This creates pressure differences inside the house, leading to drafts, uneven heating, or even backdrafts where exhaust air re-enters the living space.
6. Overloading the System with High Humidity
Indoor activities like drying clothes, cooking, and showering can significantly increase humidity levels during winter. This puts extra strain on the MVHR system as it works to remove excess moisture. High humidity can lead to condensation on windows and walls, creating an ideal environment for mould growth.
7. Blocked Condensate Drain
The condensate drain removes moisture that accumulates during the heat recovery process. In winter, this drain can become blocked or freeze, causing water to back up into the system and potentially damaging components or leading to leaks.
Preparing Your MVHR System for Winter
Follow these steps to ensure your MVHR system is winter-ready:
1. Inspect and Replace Filters
Filters are essential for maintaining indoor air quality and ensuring efficient operation. During winter, your MVHR system will work harder to ventilate your home, making clean filters even more critical.
Why it matters:
Dirty filters restrict airflow, forcing the system to work harder, which can increase energy consumption and wear out components. Filters clogged with dust and debris may also fail to capture allergens and pollutants effectively, compromising air quality.
What to do:
Inspect filters before winter begins and replace them if necessary. Most MVHR systems use G4 or F7 filters, which should typically be changed every six months. However, homes in areas with higher pollution or households with pets may require more frequent changes.
2. Check and Insulate Ductwork
Properly insulated ductwork is essential to prevent condensation during colder months. When warm indoor air meets cold surfaces in poorly insulated ducts, condensation can form, potentially leading to water damage and mould growth.
What to do:
Inspect the ductwork, especially in unheated areas such as attics or basements, for signs of wear or insufficient insulation. Adding or replacing insulation can prevent temperature differences from causing condensation inside the ducts.
3. Ensure the Condensate Drain Is Clear
During winter, the MVHR system extracts moisture from the indoor air as part of its operation. This moisture is drained away through a condensate pipe, which can freeze or become blocked in colder conditions.
Why it matters:
A blocked or frozen condensate drain can cause water to back up into the system, potentially damaging internal components and leading to leaks.
What to do:
Clear the condensate drain of any debris and ensure it is adequately insulated to prevent freezing. Check the drain regularly throughout winter to avoid unexpected issues.
4. Balance the Airflow
Balancing the supply and extract airflow is crucial, especially in winter when homes are sealed tighter to retain heat. Imbalances can lead to drafts, uneven heating, or backdrafts, where exhaust air re-enters the living space.
What to do:
Use your system’s controls to ensure the airflow rates are balanced. If you’re unsure how to do this, consult a professional technician to recalibrate the system.
5. Schedule a Professional Service
Routine maintenance is vital for keeping your MVHR system running efficiently, particularly before the winter months when it will be in higher demand. A professional technician can identify and address potential issues you might overlook.
What’s included in a service:
- Inspection of filters, ducts, and the heat exchanger.
- Cleaning components as needed.
- Verifying frost protection, airflow balance, and other system settings.
Final Thoughts
Preparing your MVHR system for winter is essential to maintain a warm, healthy, and energy-efficient home. By following these maintenance steps, you can ensure that your system performs optimally during the colder months and beyond.
If you’re unsure about performing maintenance tasks yourself or notice any issues, don’t hesitate to contact a professional. A little preparation now can save you from costly repairs and discomfort later.
For more tips on maintaining your MVHR system or to schedule a service, get in touch with us today. We’re here to help you make the most of your system, no matter the season.