Mechanical ventilation with heat recovery (MVHR) systems are an essential component for creating a healthy, comfortable, and energy-efficient living environment. But with so many options available, choosing the right MVHR unit for your project can feel daunting. 

Here, we walk you through the key factors to consider, helping you select the best MVHR system for your specific needs.

Understanding MVHR systems

MVHR systems work by extracting stale air from wet rooms (such as kitchens and bathrooms) and supplying fresh air to living areas (such as bedrooms and living rooms). The heat from the extracted air is transferred to the incoming fresh air via a heat exchanger, significantly reducing energy loss. This process not only improves indoor air quality but also helps maintain a consistent temperature, enhancing your home's overall energy efficiency and comfort.

Key factors to consider

From home size and layout to climate considerations and budget to system efficiency ratings, there are a few crucial elements to weigh up before coming to a decision. 

1. Home size and layout

The size and layout of your home are crucial when selecting an MVHR system. Larger homes or properties with complex layouts may require more powerful units or multiple systems to ensure efficient air circulation. Key considerations include:

• Airflow capacity: Measure the total floor area and volume of your home to determine the required airflow capacity. MVHR units are rated by their ability to move air, typically measured in cubic meters per hour (m³/h).
• Ductwork design: The design and installation of ductwork can impact system efficiency. Ensure your MVHR unit can accommodate the ductwork needed for your home’s layout.

2. The climate

Your local climate plays a significant role in determining the best MVHR system for your home. In colder climates, efficient heat recovery is crucial, whereas in milder climates, balanced ventilation might be more important.

• Frost protection: In cold regions, choose a system with effective frost protection to prevent the heat exchanger from freezing.
• Summer bypass: This feature allows the system to bypass the heat exchanger during warm weather, helping cool your home naturally.

3. Budget

Your budget will influence the range of MVHR units available to you. While higher-end models offer advanced features and greater efficiency, there are also budget-friendly options that provide excellent performance.

• Initial cost vs. long-term savings: Consider the initial investment in the context of long-term energy savings and maintenance costs. Higher efficiency units may have a higher upfront cost but offer significant savings over time.
• Grants and incentives: Research available grants and incentives for energy-efficient home improvements in your area. These can help offset the cost of a new MVHR system.

4. System efficiency ratings

Efficiency ratings provide a benchmark for comparing different MVHR units. Look for systems with high heat recovery efficiency and low specific fan power (SFP) ratings.

• Heat recovery efficiency (HRE): This measures how effectively the system recovers heat from the extracted air. Higher HRE means better energy savings.
• Specific fan power (SFP): Indicates the power consumption of the fans relative to the airflow provided. Lower SFP values mean greater energy efficiency.

Consulting with suppliers and installers

• When discussing your project with MVHR suppliers and installers, use the following checklist to ensure you cover all critical aspects:Home assessment:
  • Have you measured the total floor area and volume of your home?
  • What is the layout of your home, and how will it affect ductwork design?
  Climate suitability:
  • Does the MVHR unit have adequate frost protection for cold climates?
  • Is a summer bypass feature necessary for your region?
  Budget and costs:
  • What is the initial cost of the MVHR system, and what are the expected long-term savings?
  • Are there any available grants or incentives that can help reduce costs?
  Efficiency and performance:
  • What are the heat recovery efficiency and specific fan power ratings of the unit?
  • How does the system compare to others in terms of energy efficiency?
  Maintenance and support:
  • What are the maintenance requirements for the MVHR system?
  • What kind of support and warranty does the supplier and installer provide?
  By carefully considering these factors and asking the right questions, you can confidently select an MVHR system that meets your needs, enhances your home’s energy efficiency, and provides a comfortable living environment.Choosing the right MVHR unit for your project is a significant decision that can have a lasting impact on your home's comfort and energy efficiency. At 21 Degrees, we’re committed to guiding you through this process with expert advice and tailored solutions. Whether you're building a new home or upgrading an existing one, our team is here to help you find the perfect MVHR system. 

Get in touch for a consultation and take the first step towards a healthier, more energy-efficient home.