Summary: It used to be very common to save energy in dwellings by turning off the heating and ventilation during the night. Windows could then be opened to improve air quality. Today, bedrooms are kept warm because they are used for many other activities, so leaving bedroom windows open at night wastes energy, while closing them leads to poor air quality. An energy-efficient solution to this dilemma would be to install counter-current heat exchangers in bedrooms, heating the incoming air by bringing it into contact with exhaust air, and sealing the bedroom door to improve the thermal and acoustic insulation of the bedroom from the rest of the dwelling.

The project will: a) examine the energy saving potential of this proposed solution; and b) determine how sleep and next-day well-being are affected by different combinations of bedroom air temperature and outdoor air supply rate, to provide an empirical basis for cost-benefit analysis and technical optimisation. Discovering how sleep is affected by bedroom temperature and air quality is an essential first step towards the effective use of energy in dwellings for 8 of the 24 hours of each day. At present, the conditions selected for daytime activities and clothing are simply assumed to be appropriate for sleep. The project will test that assumption.