A single detached house can vary drastically from a traditional Japanese house with a large lot of land in a rural area to a modern, 3-story, narrow/slim design in an urban area surrounded by towering apartment buildings. Space can range anywhere from 50 m² to 300 m² or more. More modern houses will have at least two toilets--one on the first floor and one on the 2nd floor. have a larger system kitchen with 3 burners, 1 larger bedroom and 2 or 3 smaller bedrooms, 1 or 2 balconies, a dressing room/washroom with a large vanity,  space for a washing machine, and a large bathroom. Some houses may have tatami mats in 1, 2, or 3 bedrooms, or may have no tatami mats at all.

The biggest cost associated with a house is the land. So depending on the owner's budget, you may have a large lot with a smaller house, or a smaller lot with a larger house that often has 3 floors.  

Houses with modern amenities are not readily found at reasonable prices in urban areas. However, once you reach the suburbs or rural areas, there can be some nice houses are more reasonable prices. Only drawback being that commutes will often entail driving to work or taking a bus to reach the nearest station. 

Buyers of this type of property may be using the house as a permanent home or as a vacation home.