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Home performance contractors.


Optimisation of insulation measures on existing buildings.

In Sweden, the activity on building new residences has been decreased for a number of years. The building stock as an average has therefore become older and in the future it will be subject for refurbishment. This paper deals with how to optimise retrofit measures, i.e. how to act in order to minimise the Life-Cycle Cost (LCC) of a building. Insulation measures are emphasised but also other retrofits are dealt with such as changing the heating system. It is shown that the heating system has a vital influence on the optimal amount of extra insulation which is to be applied.

A farmhouse renovation.


Moisture in the roofs of cold storage buildings.

The low-slope roofs of ten cold storage buildings in the Dallas area were examined visually and thermo graphically (Tobiasson and Korhonen 1985) from above and below. Two inch (51 mm) diameter cores were taken to verify infrared findings and to determine moisture contents for estimating wet thermal resistances (Tobiasson et al. 1991 ). Twelve inch (0.3 m) square specimens of many of the insulations were removed for laboratory studies of their thermal properties and structure.

Impact and stability of closed airflow paths inside insulated structures.

In insulated structures, air voids and cracks allow for airflows driven by temperature differences, i.e., natural convection. The airflow paths often exist in structures built with bad workmanship, but sometimes even with the best workmanship they are difficult to avoid. Air paths within new types of loose-fill insulation may also occur. For horizontal structures, critical channel flow Rayleigh numbers can be identified for the onset of convection.