Impact of Outdoor Air Exchange Rates on Sleep Quality and the Next-Day Performance with Application of Energy Recovery Ventilator

Abstract

Sleep quality can affect human health and the next-day performance. High indoor CO2 concentration levels due to insufficient supplied air ventilation could cause poor sleep quality. Bedrooms in condominium in Thailand commonly use a wall mounted split type system without supplied outdoor air ventilation. The rooms are typically constructed having airtight envelope which have air infiltration rates ranging 0.4-0.64 ACH. This study aims to evaluate the impact of increased ventilation rates on sleep quality and the next-day performance, which the surveys were collected from two occupants living in a one bedroom condominium. The field measurement and survey were conducted for twenty days with supplied outdoor airflow rates at 0, 40, and 60 m3 hr-1 through an energy recovery ventilator (ERV). The room air exchange rates were calculated from a linear regression method obtained from a decay tracer gas technique using indoor carbon dioxide generated by occupants. To overcome the maximum limit of CO2 concentration level specified in the standard health guidelines, the ERV unit has to supply outdoor air ventilation rate at 60 m3 hr-1. Overall, the increase of outdoor air ventilation rates can improve sleep quality by 2-13 percent and occupants have better work performance in the next day by 2-20 percent. The increase of outdoor air ventilation through the ERV unit does not affect indoor relative humidity.