When our homes cannot breathe
Studies show that people spend close to 90 percent of their time indoors. But after weeks of continuous rain in Luzon, many of us may have been spending practically our entire day inside our homes.
During heavy rains, our first concern is keeping water out. We check roofs, windows, and walls for leaks and protect our homes from flooding. But even a completely leak-free home can develop another problem: Too much moisture inside and too little opportunity for it to escape.
Potential problems
We see the clues around us. Clothes hung indoors take forever to dry. Towels remain damp. Bathroom floors stay wet longer. Cabinets begin to smell musty. Mold appears on wooden furniture, leather goods, and other surfaces.
Under prolonged damp conditions, we may even see fungal growth where we least expect it. And not all this water comes from the rain.
We produce moisture inside our homes every day. We release it through breathing, cooking, bathing, washing, mopping and drying clothes. Indoor air quality guidance identifies excess moisture as a potential indoor air problem.
Inadequate ventilation can allow humidity generated by people, bathing, and cooking to accumulate, contributing to condensation, deterioration of materials, and mold.
This becomes more noticeable when windows remain closed for days. Modern homes and condominium units can also be relatively airtight. This helps us control indoor temperatures, but without enough ventilation, moisture and indoor pollutants can accumulate.
Managing moisture
The solution does not necessarily begin with buying another appliance. It begins with managing moisture at its source.
Use kitchen exhaust when cooking and cover boiling pots. Run bathroom exhaust fans during and after showers. Wipe wet floors, counters, and bathroom walls rather than allowing all that water to evaporate indoors.
When possible, avoid drying large loads of laundry inside bedrooms and living areas. Even something as simple as squeezing towels properly before hanging them reduces the amount of water that must eventually enter the air.
Then, keep air moving. Ceiling and portable fans do not remove moisture from the home, but air movement helps wet surfaces dry and reduces stagnant pockets behind furniture.
Give cabinets and large furniture some clearance from walls. Occasionally open closets and avoid packing clothes too tightly.
Natural ventilation
Whenever the rain stops and outdoor conditions permit, take advantage of short periods of natural ventilation.
Opening windows or doors on opposite sides can encourage air to move through the home. Natural ventilation uses wind and differences in indoor and outdoor temperature to create airflow.
Airconditioning can also help because cooling equipment removes some moisture while operating.
But cooling, ventilation and dehumidification are not the same thing. A room can feel cold and still have a moisture problem. Building science therefore considers the balance between moisture being added by occupants and activities and moisture being removed by cooling, ventilation or dehumidification.
A small digital humidity meter can be useful, too. Rather than simply judging whether a room feels hot or cold, we can observe its temperature and relative humidity and recognize when damp conditions persist. Temperature matters because relative humidity changes with temperature.
For persistent problems, a dehumidifier or properly designed mechanical ventilation may be worth considering.
But before buying equipment, investigate the source. Look for hidden leaks, condensation, inadequate bathroom or kitchen exhaust, damp materials, and areas where air cannot circulate. Mold that repeatedly returns after cleaning is often telling us that the moisture problem itself has not been addressed.
Resilient design
The rainy season reminds us of another dimension of resilient design. Keeping rain outside is only half the job. We must also manage the moisture we create inside.
Perhaps this is a question designers, developers, and homeowners should increasingly ask: Can our homes still breathe when we cannot open the windows?
The author is a LEED Fellow, ASEAN Architect, UAP Fellow, and educator with over 25 years of professional practice in architecture and sustainability
