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Insulation of ducts in cold attics
To benefit from the unit’s high recovery potential (efficien-
cy), the ducts must be correctly insulated.
Supply air and exhaust air ducts
In order to minimise heat loss from the duct system in cold
attics, supply air and exhaust air ducts must be provided
with at least 100 mm of insulation. If insulation from
alternative A is used, it is recommended executing with two
layers of 50 mm lamella mats with paper or foil externally
and with staggered joints between the two layers. If the
ducts are laid on the main beams of truss frames, alterna-
tive B can be used. The insulation must always be packed
tightly around the ducts.
Outdoor air and exhaust air ducts in cold areas
It is recommended to insulate ducts for outdoor air and
exhaust air ducts with at least 50 mm insulation. The
outdoor air duct is insulated to prevent warm air in the
attic from heating the fresh air in the summer. Be sure to
seal the connection where the outgoing duct passes
through the roof or gable to prevent condensation damage.
Insulation of ducts in heated rooms
Genvex recommends the following:
Supply air and exhaust air ducts
In a warm attic, the supply air and exhaust air ducts must
be provided with 50 mm of insulation finished with alumini-
um foil. Supply air and exhaust air ducts routed through
heated rooms in the home do not need to be insulated
unless cooling, a bypass or a geothermal heat exchanger
are used. In this case, the supply duct must be insulated.
Outdoor air and exhaust air ducts
In warm attics and heated rooms in the home, outdoor air
and exhaust air ducts must be insulated with a minimum of
50 mm insulation. In addition, the insulation must be lined
on the outside with cling film or aluminium foil to avoid
condensation inside the insulation.
Contact your local supplier for advice on the national
insulation guidelines.
When using a geothermal heat exchanger, it is recommend-
ed to add 100 mm of insulation to the outdoor air duct.
