1/ Structural Changes In The Construction Of Residential & Buildings

Modern homes are structurally quite different from traditional style houses. Reinforced concrete buildings, collective housing and prefabricated houses use aluminium sashes, making them air tight. The size of rooms have also been reduced.

The residential property in Vietnam : High residential building become more popular in Vietnam city. This modern material with higher air tightness. Too many room with good privacy, oppositely, very poor air circulation Natural ventilation cannot remove the accumulated moisture after hot shower.

2/ Increase In Heat Sources

Improvement in living standards has increased heat sources in the home. Cooking appliances, water heaters and other heating instruments reduce oxygen levels, causing unhealthy living conditions

3/ Increase In High-Rise Buildings

High-rise apartments, flats and offices today tend to be compact, thus restricting proper ventilation.

4/ The Increase Usage Of Air Conditioning

The advent of air conditioning has created more and more closed style houses. Air conditioning in closed rooms leads to poor ventilation, resulting in residual dust and less fresh air.