FREE DELIVERY ON MVHR UNITS - LAST DAY FOR SENDING 23RD DECEMBER

Published: 13 December 2024

Retrofit MVHR System: Challenges and Considerations

When considering the installation of a MVHR Systems in an existing home, there are unique challenges and factors to address. These considerations ensure that the system is efficient, functional, and tailored to the specific needs of the property.

When considering the installation of a MVHR Systems in an existing home, there are unique challenges and factors to address. These considerations ensure that the system is efficient, functional, and tailored to the specific needs of the property.

Key Challenges of Retrofitting MVHR Systems

1.    Void Space Limitations

Older homes often have smaller ceiling voids and solid brick walls, making it challenging to run ductwork!

Solution: Semi-rigid ductwork, such as Ubbink’s AE55Sc, is ideal for these tight spaces due to its flexibility and ease of installation.

2.    Joist Type and Location

Many older homes use steel beams, which cannot be penetrated for ducting as this compromise’s structural integrity.

Solution: Alternative routes, such as utilising stud walls or boxing in ductwork, can accommodate these constraints while maintaining the structure's safety!

3.    Flow Rate Considerations

The small size of standard 90mm semi-rigid ducting (approximately 6000mm² free area) means it is prone to high-pressure drops, which can affect performance.

Solution: Plan for dual runs of semi-rigid ducting to each plenum where needed. Budgeting for additional duct runs and ensuring space for installation is crucial!

4.    Unit Positioning

Limited utility space in older properties can make finding an appropriate location for the MVHR unit challenging…

Solution: Placing the unit in a loft can be viable if the loft is within the thermal envelope of the property to prevent condensation, non-living spaces are preferable!

5.    Airtightness (Infiltration)

MVHR systems perform best in airtight properties. Older homes often exceed the ideal airtightness level of 3m³ at 50 Pa, leading to efficiency loss.

Solution: Addressing drafts and improving the building’s airtightness can significantly enhance the system’s performance and heat recovery efficiency.