【注文住宅】間違った乾燥対策は絶対やめて！浴室換気の正しい使い方

The dangers of leaving the bathtub lid open to combat winter dryness. That shortens the lifespan of your house. Have you ever heard the advice to use leftover bathwater and humidity as a humidifier to combat winter dryness? Actually, this is a dangerous practice that can rot your house, especially in highly airtight and well-insulated homes. In this video, a housing performance expert addresses a pressing question from a homeowner who built a high-performance home (C-value 0.6/Ua 0.4). Why does this well-intentioned habit lead to mold and condensation? We'll thoroughly explain the correct ventilation time and the true reasons why you should prioritize airtightness (C-value). 1. Three reasons why you shouldn't use bathroom humidity for humidification: Trying to use bathroom humidity disrupts the entire house's ventilation system. Mold and spore diffusion: Air containing dirt unique to the bathroom flows back into the living room. Risk of condensation within walls: Moisture cools in hallways and closets with temperature differences, causing condensation in unseen areas. Failure of ventilation design: Air returns from areas that should be discarded as "dirty air," leading to stagnant air. 2. "Correct Humidification and Ventilation in Winter" as Taught by Housing Performance Professionals Ventilation Time Guidelines: For homes built after 2003, 24-hour ventilation is a prerequisite. For bathroom ventilation, aim for drying 4-5 hours after bathing. The Best Humidification Method: "Drying clothes indoors" is the most hygienic and effective method, rather than using a humidifier which requires extensive maintenance. The Difference Between C-Value 1.0 and 0.1: The idea that "airtightness is acceptable if there are ventilation openings" is a big mistake. We explain why high airtightness is necessary based on comparative data of hole sizes. Frequently Asked Questions (FAQ) Q: I'm worried about the electricity bill if I run the bathroom exhaust fan 24 hours a day. A: With modern DC motor-driven ventilation fans, even running them 24 hours a day only costs a few hundred yen per month. Compared to the repair costs of damage caused by condensation, this is an extremely low cost. Q: Which is better, using a humidifier or drying clothes indoors? A: As explained in the video, if you neglect to clean the filter of a humidifier, it will spread bacteria. Drying clean clothes indoors is the most rational humidification method that takes advantage of the house's performance. Q: Even if the C-value is somewhat poor, can't I solve it by running the ventilation fan at full power? A: In a house with many gaps, running the ventilation fan allows air to enter from unintended places (gaps), making planned ventilation impossible. Increasing the C-value is about gaining "control over ventilation." #HighAirtightnessHighInsulation #CustomHomes #VentilationSystem #CValue #DrynessPrevention #CondensationPrevention #MyHomePlanning #EnergySavingHomes #JapaneseLivingEnvironment