How to Live Healthy and Mold Free in Small Tight Homes

Living in Tight Places

Living in small tight homes might be hazardous to your health if you do not take

these steps highlighted here. If you live in small tiny quarters, the air quality
dynamics are crucial and more sensitive as compared to normal living spaces.
Certain critical considerations which we normally take for granted must be
carefully looked at. Mold and mildew require three things to grow.

  1. Moisture
  2. Food
  3. Still stagnant air

Inorganic materials with a biofilm can be sufficient to change dormant mold
spores in the air we are breathing right now into active fungus growth.
The flowing steps are intended to deprive of one or more of these factors for
mold growth.



The flowing steps are intended to deprive of one or more of these factors for mold growth.

 1. Make sure there is adequate ventilation. In a small living space in harsh weather conditions, this may not be as easy as it sounds. Often, to keep the weather conditions from the room, proper mechanical sealing and insulation of the doors and windows are done to keep the room from the extreme heat or cold outside. This often in itself becomes the source of the problem. If a small room too tightly sealed, ventilation is stifled. Remove or reduce weather seals to allow for the right amount of air inlet into the space. As weather permits, regularly open windows and doors to allow full circulation to channel fresh outside air right through the room.

Mold growing on Wall

2. Exhaust all high concentration of moisture at the source. This means a ducted cooker hood and exhaust fan for the shower. These exhaust systems need to be checked for CFM airflow rate to make sure that they are working properly. If the room is too well sealed, these ventilators will not work properly. See tips below on how to do that.

3. Vacuum and wipe down the room regularly to keep the level of dust particles in check. Most of these dust particles are skin flakes and linen fiber. Frequently wash bed sheets and linens to minimize fibers and skin flakes build up. In clean room operations in wafer fabs for IC making, skin flakes have been identified as the number one culprit to particle contamination. It is by far the largest source of particle generation.

 4. Clean the air conditioner regularly to prevent biofilm from forming in the fins. Biofilm is formed from the dead skin flakes from the human body. Because there is a layer of oil on our skin, these skin flakes will stick onto any surface they come into contact with, especially the path of the airflow in a ductless air conditioner, i.e. the cooling fins and the rotor blades. Bacteria colonies will form on these skin layers producing a bio-slime which in turns binds more tightly on the surfaces they adhere to. As the biofilm get thicker and covers more surface of the cooling coil and fins, they lose their hydrophilic properties preventing the condensate from draining off. This in turn reduces the air conditioner's ability to dehumidify the room especially from moisture sources like hot showers. At the same time, the skin flakes also become a food source for mold as well. Once mold take root in the air conditioner, it can spread spore all over the room; on the ceiling, under the mattress, on the walls. Practically, you could see mold growing where the air is the most stagnant. By cleaning the air conditioner, just plain vacuuming or brushing is not sufficient. Some type of chemical solution cleaning system is absolutely necessary to keep the ac unit clean and fully operational. 

 4. Avoid leaving the air conditioner turned on all the time. This could mean it is less likely that adequate ventilation will be practiced to avoid wasting conditioned (cooled or warmed) air.




  • To find if the room is not too tightly sealed, check the CFM airflow rate at the outlet of the exhaust with an anemometer or airflow meter. With the door and windows closed. (CFM airflow is the rate at which a certain volume of air moves in a certain period of time. CFM stands for cubic feet per minute)


  • The airflow should approach the actual rating of the exhaust system. If the exhaust is significantly (say 50% or even lower) less than the actual rating, you might reduce the mechanical sealing of the room. For every exhaust, there must be adequate air inlet in order for the exhaust ventilation to work properly. According to ASHRAE standard 62-89 approved in 1989, all living spaces must have at least 0.35 ACH (air exchange rate) . What this means is there must be at least 35% of the air in a room must be changed out in every hour. A calculation can be made to find out the adequate CFM required for a given room size.


  • A split ductless air conditioner is the air conditioner of choice for tight spaces since it mounts on the wall away from the floor maximizing the space while giving the necessary power and coverage for both heating and/or cooling. It is important to clean these air conditioners properly.



  • Read "How To Remove Mould from Wall Air Conditioners" for clear instructions how to do this without creating a mess. Find out how using an aircon wash bag can enable cleaning the fan coil and the rotor blades in one go without dismantling the system off the wall.







  • Given the right conditions, mold growth acceleration is logarithmic.


  • Of the 3000 species of mold, about 40 are considered toxic.


  • Apart from mold, oxygen deprivation and carbon dioxide buildup can easily be the result of insufficient ventilation which can result in frequent headaches and nausea.


  • The dangers of a ductless split air conditioner is that it is ductless. There is no path leading to outside air. Hence, adequate and frequent ventilation must be designed in elsewhere in the room.