Measured performance of conventional and high-velocity distribution systems in attic and space locations

Residential distribution systems are inherently inefficient at delivering heated or cooled air to the conditioned space as the result of poor design and installation practices. Examples of some of the more common problems include heat loss/gain in unconditioned spaces and leakage through supply and return ducts. These defects can result in significantly increased energy consumption, poor thermal comfort, and high peak electricity demand. Efforts to improve distribution systems

Convection in loose-fill attic insulation - simulations and large-scale measurements.

Heat transfer in loose-fill attic insulation was investigated in a large-scale model of a ventilated attic built in a climatic chamber. The particular aspect of this study was heat transfer by convection and its effect on heat losses through the attic floor. It was shown by thermal resistance measurements that the measured and calculated thermal resistance of the attic floor is within the margin of error. Air movements were detected in the insulation, sufficient to cause a decrease in the thermal resistance of the attic floor.

Practical implications of the elimination of natural attic ventilation in mixed climates.

Mould, wet insulation, wet or weakened wood or premature aging of roof coverings often leads to the addition of extra ventilation in attics at time of renovation. The study develops a protocol to determine the effects, surveys several occupied buildings to establish why the ventilation was added, and establishes a base to analyse the effect of the installation.

Guidelines for ventilating attics and cathedral ceilings to avoid icings at their eaves.

Describes how design aids were developed to simplify the task of sizing inlet and exhaust openings and airway height for cathedral ceilings. Recommends guidelines for when and where roof ventilation is needed to avoid icings at eaves.

Observing Mother Nature in action: moisture problems in buildings in the southeast.

Presents a selection of moisture problems encountered in the south eastern USA. Discusses moisture in attics, moisture in floor cavities, moisture inside the house, hardwood floors with moisture problems, and vented crawlspaces.

Insulating your house.


Ventilating an attic.


Convective processes in loose fill attic insulation - metering equipment.

A large-scale model of an attic construction has been built in a climatic chamber. The purpose of the attic test model is to investigate hear transfer-in particular, heat transfer by convection-in loose-fill attic insulation. The influence of a number of factors on heat flows can be investigated using the attic test model; for example, insulation thickness, attic ventilation, ceiling construction, roof slopes, and the quality of installation workmanship. The heat flow through the attic ceiling construction is measured with a metering box.