tight house

Briefly reviews ways of reducing levels of pollutant in the house. Concludes that the best method is to ensure adequate ventilation. Considers how this can be done whilst still conserving energy including the use of mechanical ventilation systems with heat exchangers in tight houses. Concludes that making houses tighter as an energy conservation measure should be approached with caution, as the identification of indoor pollutants and the introduction of indoor air quality standards is still in its infancy.

Describes intiatives made in North America to reduce energy consumption in buildings. Most energy utilities finance energy efficiency improvements on their customers premises. Reports on super-insulated housing and how this type of construction is being implemented in Canada.

Reports air tightness measures and variations in 14 low-energy houses in Heimdal, plus testing of energy saving measures for exposed detached houses. The air tightness should be considerably improved according to the regulations. Treats principles of air tightness, pressure measurement, thermography tracer gas measurements and heat loss measurements.

Measures the airtightness of various types of 25 residential units (9 detached houses and 16 apartments) using the fan pressurization technique. Shows the relationship between the pressure difference across the building envelope and the volumetric flow rate of air as well as the ratio of the effective leakage area of one building element to the total leakage area. Compares the airtightness of various types of houses in different countries using the valueof the effective leakage area per floor a at a pressure difference of 10 Pa.

Reports conclusions from projects investigating the tightness of buildings sponsored by the Ministry of Trade and Industry. Describes factors influencing ventilation such as size and shape of building, location, distribution of leakage points, interior air flow paths and the design and control of ventilation. Wind condition and temperature difference are the only driving forces in natural ventilation, in mechanical ventilation the temperature has only a limited influence but the wind may cause considerable draught in an untight building.

Reviews the energy conservation features employed in most low energy houses in the Prairie region including airtightness (by application of a vapour barrier), increased thickness of insulation, air-to-air heat exchangers and south-facing windows. Discusses the performance of low energy houses in Saskatoon, and the cost of energy conservation features.

States that in a tight house with a vapour barrier, an air management system is needed to provide fresh air and remove the build-up of moisture generated by the occupants. Briefly describes a typical air management system,incorporating an air-to-air heat exchanger, and discusses the need to provide an acceptable ventilation rate, which controls pollutant level but minimizes heat losses.

Describes a field method for surveying residences for indoor air quality. The method requires 2 days of field testing for each residence - a day to perform a multipoint tracer gas study to characterize the ventilation efficiency of the various spaces in the house and to determine the overall air change rate; and a day to measure contaminant concentrations in locations selected according to the results of the tracer gas study and contaminant generation locations. Describes and discusses results obtained by this surveying procedure in 3 energy efficient residences.

Subjects 11 private dwellings at Taby and 5 at Brunna (all 2-3 yrs old) to repeated airtightness tests over a period of two years. Finds the largest leakage is 2.5 ach and the mean leakage is 1.6 ach. Immediately after its completion, the air tightness of a building undergoes a certain deterioration, after which it stabilizes. Over the 2yr. measuring period the changes are small, and could all be attributed to occupancy effects. Leakage paths occurat the junctions of wall and ceiling and wall and floor, and at service entries.

Discusses the Hjortekar project of 6 low energy houses, built as part of the Danish Energy Research and Development Programme. Explains some of the construction details to avoid cold bridges and ensure airtightness. Test results of infiltration air change rates range from 0.02 to 0.12 ach, while other tests show less than 15% difference between calculated and measured transmission heat losses, which range from 70-155 w/degree C.