Bangkok maintains average relative humidity of 75-80% RH year-round — significantly above comfortable levels for elderly residents. However, applying uniform dehumidification throughout the entire home is not the correct approach, as different rooms have distinct humidity requirements.
Optimal RH targets by room type: bedrooms at 45-55% RH (as recommended by the National Sleep Foundation) for quality sleep and reduced dust mite proliferation; bathrooms tolerate 60-70% RH with adequate ventilation but must not exceed 70% to prevent mold growth; living rooms at 50-60% RH for comfort and air quality; and kitchens at 45-55% RH to manage cooking steam.
Two primary options exist for ventilation combined with humidity control: ERV (Energy Recovery Ventilator) is ideal for Bangkok’s hot-humid climate as it removes excess moisture while bringing in fresh filtered air, priced at 15,000-35,000 THB installed by an HVAC technician; HRV (Heat Recovery Ventilator) is better suited for cooler climates at similar prices but performs less effectively in tropical conditions.
Moisture-resistant materials for renovation: porcelain tiles with COF ≥0.6 both wet and dry for bathrooms and kitchens; 100% waterproof LVT (Luxury Vinyl Tile) for bedrooms at 250-450 THB/sqm; MR Gypsum (Moisture Resistant) board for bathroom walls replacing standard gypsum; and anti-fungal paint eliminating 99% of mold growth.
Case study: a Sathorn townhouse second-floor bedroom measured 70% RH with black stains on the ceiling. The 68-year-old resident suffered frequent allergy symptoms. After installing an Aqara Temperature & Humidity Sensor (590 THB) connected to Home Assistant controlling a 16L/day Smart Dehumidifier, humidity dropped to 52% RH within three weeks and allergy symptoms decreased significantly.