Wood can't continually absorb moisture, at some point it would become saturated. I always thought that the reason that winter air is dry is because warm air ca

Wood can't continually absorb moisture, at some point it would become saturated. I always thought that the reason that winter air is dry is because warm air can hold more moisture than cold air, so as you heat it, relative humidity decreases. So, for example, if it's 5C outside with 50% relative humidity, if you heat that air to 22C, then it will have only 17% relative humidity. But modern houses (even wood ones) are so well sealed that even in winter you could end up with too much humidity inside just from normal activities (cooking, bathing, breathing).