Overheating risk barriers to energy renovations of single family houses: Multicriteria analysis and assessment

Many post-occupancy comfort studies of energy renovated residential buildings have documented elevated temperatures above comfort levels, not only during the summer period but also during the shoulder months. The main focus in renovation projects is on heat savings while the risk of overheating is not considered.

Annual characteristics of ventilation and indoor air quality in detached houses using a simulation method with Japanese daily schedule model.

In order to explain the effect of ventilation systems, the article presents the results of investigations made on a simulation program to calculate the temperature, heat loads, ventilation rates and indoor air quality. The study considered the Japanese daily schedule and the residents behaviour in regard to maintaining comfort. The indicators of indoor air quality were taken to be carbon dioxide, carbon monoxide and formaldehyde concentrations. Three systems were analysed: basic passive ventilation system, a passive stack ventilation system and a mechanical ventilation system.

Test method of heat recovery units in single houses.

The study was to test five units used in single house mechanical ventilation systems with heat recovery. Tests were made according to CEN project prepared by CEN TC 156/WG2/AH7 including air tightness, pressure-airflow's curves and temperature ratios. A full test on frost and condensation was also realised on one unit to determine the influence of these parameters on performances. Test results, influence of wet or dry conditions and main conclusions for using these results in dimensioning, will be given.

Good indoor climate and air quality in energy efficient houses.

Two energy-efficient single-family houses (known as ESPI houses) with competitive overallcosts were set up during the study in Finland. The consumption of energy for room heating inESPI houses was reduced to a half at the construction stage, by employing simple solutionswhich can be used by every builder. The level of thermal insulation of the houses wasimproved remarkably. The houses were equipped with a controlled ventilation system and anefficient exhaust air heat recovery unit. One of the houses was oil heated and the other waselectrically heated.

The influence of the occupants and the construction period on the resulting indoor environment.

This study, in progress in Trondheim, Norway, deals with the connection between energy economy and indoor air quality in detached houses. It includes 41 new houses, all equipped with balanced ventilation and heat-pump for energy savings. The study includes both questionnaires and various measurements, and will be finished in 1994. Comparing the new and old housing, 90 % of the occupants are more satisfied with the indoor air quality in their new home, than their old home.