The interior of the house should be ventilated as much as possible, each room should have windows, and the lighting area on the sunny side should not be less than 40% of the room area.
As for the bathroom, it is best to put it on the first floor, because after a long time, waterproofing will cause problems; The bathroom does not affect.
As for the third floor, it's best to make a sun room with a terrace, which can transmit light as much as possible, reduce the accumulation of Yin Qi and avoid a fully enclosed structure.
As for the surroundings of the house, try not to plant too tall plants and put them in the sun. Never choose willow as a tree species, willow is a shade tree species.