Reports on single family dwellings fitted with energy-saving ventilation unit. Quotes energy savings of 10,000 Kwh/annum. Points out that adequate indoor climate can be maintained through tight houses, mechanical ventilation and heat recovery as opposed to airing rooms by opening windows.
In terms of energy usage and indoor climate a building works as a total system where the shell, the installations and services interact organically. However, technical knowledge of this total system is still undeveloped and the limitations of different trade categories hinders such development. Examples show how the efficiency of building methods such as tightening external walls depend on the ventilation system used in the building.
Reviews factors affecting indoor air quality, including the effect of mildew, high concentrations of microorganisms, radon, light air ions and chemical pollutants(especially formaldehyde). These are mentioned especially inconjunction with airtight residential buildings in Sweden. Current building standards in Sweden concerning materials, airtightness, air quality and energy conservation are also reviewed, along with areas of current and proposed research in air quality.
An attempt was made to make the super-insulated Saskatchewan Conservation House as air-tight as possible, to avoid heat loss. By lapping all joints in the vapour barrier over solid backing, by continuous sealing of all joins, and by protecting the vapour barrier with solid covering, the natural air-change rate(A/C)was decreased to 1/20 change per hour. At this rate, induced air change was necessary to control odour and humidity. Most of these details could be modified to make any insulated house air-tight.
Reviews literature on the health effects of indoor air pollutants in energy-efficient homes with low ventilation rates. Discusses hazards from gas cooking, formaldehyde, radon and other pollutants. Suggests air infiltration rate of 0.5 air changes/hour to keep indoor pollution to below critical levles. Also suggests installation of an air-to-air heat exchanger or electronic air cleaner.
Notes that as houses become tighter, adventitious ventilation decreases. Discusses attitudes to varying degrees of tightness. Explains introduction of the supply exhaust system which comprises air supply, air exhaust and heat recovery. Notes requirements for economic use of the system and relates installation costs to potential savings. Tabulates systems currently available in Sweden(December 1980)noting maximum air flow, position of heat exchanger and other factors.
The perfomance of single-family houses built to the new swedish building code was considered. In the code, the requirements for thermal insulation for different building sections were strengthened, and completely new requirements for a building`s airtightness were introduced. One site- built design acheived a estimated 1/3 reduction in energy consumption, but another less airtight factory-made house showed serious shortcomings in the indoor climate acheived.
Reports results of measurements of radon gas made in each of the Saskatoon low energy houses in December 1980. Finds that gas levels were higher in basements than on the ground floor but that concentrations of radon were not high enough to constitute a health risk. Suggests that permeability of basement walls may have a great effect on radon concentration and that sealing a basement may reduce levels.
The proceedings of the Canada Mortgage and Housing Corporation industry/science seminar "Controlled Ventilation with Exhaust Air Heat Recovery for Canadian Housing" 26 October 1978
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