This system can help you avoid.
Unvented conditioned attic.
Poorly insulated ducting can cause heat loss in colder months and the loss of conditioned air in the summer in vented attics.
To provide an unvented conditioned space for locating hvac equipment in the attic and or to provide a continuous thermal barrier for designs that have complex coffered ceiling planes and or numerous penetrations for lights speakers vents soffits etc which make it difficult to achieve an airtight ceiling plane.
Making the attic a conditioned space means the space will be the same temperature as the rest of your home.
Lstiburek s enthusiasm was rooted in his desire to bring attic ductwork inside a home s thermal envelope.
The builder or homebuyer if the buyer has purchased prior to construction may want the attic space to be conditioned for additional living or storage space.
Traditionally building codes have required attic ventilation.
The advantages of the unvented conditioned attic construction are increasingly being recognized within the industry to help with the following.
Building america research has demonstrated unvented conditioned attics can substantially improve energy performance while allowing home builders to continue locating hvac systems in the attic space.
However this recommendation should be addressed on a case by case basis.
A conditioned attic requires a full commitment.
Mixing vented and unvented portions will lead to heavy condensation on the exposed roof sheathing.
Adding unvented attic insulation like spray foam seals the building envelope and stops airflow.
This air seal will.
This sheathing is less than a year old.
Other reasons for constructing an unvented attic include the following.
Among the early promoters of conditioned attics was joe lstiburek a principal of the building science corporation.
The intended purpose was to allow warm air and moisture to escape.
In most cases the existing insulation on an attic floor should be removed when an unconditioned attic is converted to a conditioned attic.
Unventilated attics are common where roof assemblies are complex and it s difficult to create a sealed ceiling plane.
Energy conservation moisture management.
Depending on the climate and the thickness of the existing insulation it may make sense to leave the old insulation in place.
