MVHR ductwork condensation control
What it looks like
Uninsulated ductwork in cold spaces can lead to condensation forming on or within ducts, causing mould or dripping.
Why it happens
MVHR ductwork requires insulation to prevent condensation when it traverses unheated or uninsulated spaces, such as roof voids, or when it carries cold air through heated parts of the building. This measure avoids moisture damage and maintains system efficiency.
What it costs if it is missed
MVHR ductwork requires insulation to prevent condensation when it traverses unheated or uninsulated spaces, such as roof voids, or when it carries cold air through heated parts of the building. This measure avoids moisture damage and maintains system efficiency.
How to inspect for it
Verify that all MVHR ductwork running through unheated spaces or carrying cold air is adequately insulated along its entire length.
How to prevent it
MVHR ductwork requires insulation to prevent condensation when it traverses unheated or uninsulated spaces, such as roof voids, or when it carries cold air through heated parts of the building. This measure avoids moisture damage and maintains system efficiency.
Basis in regulation
Last updated 23 August 2026. This is our editorial summary of publicly available regulation and site practice, not building control approval or a warranty determination.