Yes, experts affirm that retrofitting Mechanical Ventilation with Heat Recovery (MVHR) is feasible. However, it necessitates meticulous planning and potentially some concessions to ensure a successful installation.

Yes, experts affirm that retrofitting Mechanical Ventilation with Heat Recovery (MVHR) is feasible. However, it necessitates meticulous planning and potentially some concessions to ensure a successful installation.

Adding MVHR to an Existing Home: Tips and Tricks

Let's discuss the ins and outs of retrofitting a Mechanical Ventilation with Heat Recovery (MVHR) system in an existing home. While it might be easier to incorporate MVHR in a new build, it's certainly achievable in a renovation project.

Key Challenges

Integrating MVHR into an older property can present various technical hurdles. Space limitations, structural constraints, and the need for minimal disruption are common factors that can complicate the installation process.

Homes with solid timber joists, new steel beams, or unique ceiling structures may pose issues when trying to establish duct routes.

Factors Affecting Ease of Installation

The property's layout, existing ventilation systems, and level of airtightness play a significant role in how straightforward the MVHR installation process will be. Homes undergoing substantial renovation or whole-house retrofits offer the best opportunity for MVHR integration, as ductwork can be concealed more easily within floors, ceilings, or walls.

Simplifying the Process

1. Planning Ahead: Consider MVHR at the onset of any retrofit or home renovation project, allowing for better integration of duct routes and unit placement.
2. Bungalows Rule: Bungalows with existing lofts are perfect for MVHR retrofits, as all the ductwork and the unit can be housed in the loft.
3. Communication is Key: Engage in frequent discussions with the client, architect, engineer, and other trades throughout the installation process.
4. Timing: Install ducts as early as possible in the renovation, and accept that more ceilings or floors may need to come up to accommodate the ducts and vents.
5. Expertise: Rely on experienced designers and installers who understand the specific challenges of retrofit projects for a smooth installation.

Smart Design Solutions

• Compact/Decentralised MVHR units: Ideal for homes with limited space.
• Improved Airtightness: Prioritizing airtightness before or during the retrofit ensures the MVHR system operates efficiently.
• Hidden Installation: Employing creative techniques such as creating service voids behind fitted furniture or doors, using flexible ducting, or running ducts through existing bulkheads can help camouflage the MVHR install and save space.

Cost Considerations

While costs for MVHR in a new build can vary, retrofitting an MVHR system will likely be more expensive. The additional labor and design complexities involved in adapting the system to an existing structure will increase the costs. Costs often include not only the MVHR unit and ducting, but also the time required for planning, adjustments, and a careful, often bespoke installation.

Suitability for Retrofit

Although each home will need to be assessed individually, MVHR can be retrofitted into many types of homes. Homes that are particularly leaky or poorly insulated may not benefit fully from MVHR. In these cases, alternative solutions like natural ventilation or extract-only ventilation may be more suitable until the building fabric is improved.

Alternatives to MVHR

When full system installation isn't practical, other measures can help achieve similar outcomes. Options include improving natural ventilation with trickle vents and core vents, using demand-controlled extract ventilation (DMEV) or continuous mechanical extract systems to manage humidity levels, or installing whole-room or two-room through-the-wall solutions in specific areas to address air quality concerns without extensive ductwork.

FAQs

1. Are there alternatives to a retrofit MVHR system?Yes, there are. Improved natural ventilation, extract-only ventilation, demand-controlled ventilation, or wall-mounted air filtration systems can serve as alternative solutions.
2. Is a retrofit MVHR worth the disruption?While the upfront investment may seem high, the long-term benefits such as improved indoor air quality, reduced heating demand, and protection of building fabric can make it a cost-effective component of a comprehensive energy efficiency upgrade. If you want to maintain optimal humidity, minimize pollutants, and save on energy bills, then MVHR is an excellent choice.
3. Incorporating a Mechanical Ventilation with Heat Recovery (MVHR) system in an older home can present various technical challenges due to space limitations, structural constraints, and the need for minimal disruption.
4. Homes undergoing substantial renovation or whole-house retrofits offer the best opportunity for MVHR integration, as ductwork can be concealed more easily within floors, ceilings, or walls.
5. Planning MVHR at the onset of any renovation project allows for better integration of duct routes and unit placement.
6. Bungalows with existing lofts are ideal for MVHR retrofits, as all the ductwork and the unit can be housed in the loft.
7. Frequent discussions with the client, architect, engineer, and other trades are crucial throughout the MVHR installation process.
8. Engaging experienced designers and installers who understand the specific challenges of retrofit projects is essential for a smooth MVHR installation.
9. Compact or decentralized MVHR units can be a smart choice for homes with limited space.
10. Improving Airtightness before or during the retrofit ensures the MVHR system operates efficiently.
11. Alternatives like natural ventilation, demand-controlled ventilation, or wall-mounted air filtration systems may be more appropriate for homes that are particularly leaky or poorly insulated.

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