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Influence of window ventilation on indoor climate and heat loss in Swedish dwellings

Bekzhonov, Bekzhon LU (2025) In TVIT-5000 ABKM01 20251
Division of Building Services
Abstract
This thesis quantifies how everyday window opening habits affect indoor climate and heating demand in Swedish multi-family dwellings. Minute-by-minute data was analyzed that was collected for one year from 15 dwellings in northern and southern Sweden, logging window angle, air-quality indicators and temperatures indoors and outdoors. More than 17 000 discrete airing events were detected and characterized by duration, opening angle and resulting airflow and their impact was calculated using an existing airflow model based on window angle, temperature difference, and physical flow coefficients. Statistical analysis shows that temperature difference between indoors and outdoors and the length of each opening explain over 60 % of the variance... (More)
This thesis quantifies how everyday window opening habits affect indoor climate and heating demand in Swedish multi-family dwellings. Minute-by-minute data was analyzed that was collected for one year from 15 dwellings in northern and southern Sweden, logging window angle, air-quality indicators and temperatures indoors and outdoors. More than 17 000 discrete airing events were detected and characterized by duration, opening angle and resulting airflow and their impact was calculated using an existing airflow model based on window angle, temperature difference, and physical flow coefficients. Statistical analysis shows that temperature difference between indoors and outdoors and the length of each opening explain over 60 % of the variance in heat losses, while opening angle and indoor CO₂ account for smaller shares. Windows facing south caused the lowest losses, while the ones facing west produced the highest, and 10 % of events were responsible for roughly eighty per cent of the total ventilation energy loss, indicating a very skewed distribution. Seasonal auto-regressive integrated moving average modelling demonstrates that daily losses can be forecast within a half of mean value (± 38 kWh), opening the door to anticipatory HVAC strategies. The findings suggest that targeted occupant feedback on long openings during large temperature differences as well as well functioning HRV systems may reduce heating losses without compromising indoor air quality. (Less)
Please use this url to cite or link to this publication:
author
Bekzhonov, Bekzhon LU
supervisor
organization
course
ABKM01 20251
year
type
H2 - Master's Degree (Two Years)
subject
publication/series
TVIT-5000
report number
TVIT-5118
other publication id
ISRN LUTVDG/TVIT—25/5118—SE(91)
language
English
additional info
Examiner: Henrik Davidsson
id
9209549
date added to LUP
2025-08-12 17:00:31
date last changed
2025-08-12 17:00:31
@misc{9209549,
  abstract     = {{This thesis quantifies how everyday window opening habits affect indoor climate and heating demand in Swedish multi-family dwellings. Minute-by-minute data was analyzed that was collected for one year from 15 dwellings in northern and southern Sweden, logging window angle, air-quality indicators and temperatures indoors and outdoors. More than 17 000 discrete airing events were detected and characterized by duration, opening angle and resulting airflow and their impact was calculated using an existing airflow model based on window angle, temperature difference, and physical flow coefficients. Statistical analysis shows that temperature difference between indoors and outdoors and the length of each opening explain over 60 % of the variance in heat losses, while opening angle and indoor CO₂ account for smaller shares. Windows facing south caused the lowest losses, while the ones facing west produced the highest, and 10 % of events were responsible for roughly eighty per cent of the total ventilation energy loss, indicating a very skewed distribution. Seasonal auto-regressive integrated moving average modelling demonstrates that daily losses can be forecast within a half of mean value (± 38 kWh), opening the door to anticipatory HVAC strategies. The findings suggest that targeted occupant feedback on long openings during large temperature differences as well as well functioning HRV systems may reduce heating losses without compromising indoor air quality.}},
  author       = {{Bekzhonov, Bekzhon}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{TVIT-5000}},
  title        = {{Influence of window ventilation on indoor climate and heat loss in Swedish dwellings}},
  year         = {{2025}},
}