In the first stage directions, Miller goes into a good bit of detail about the setting of the play. The Kellers' house is located in the outskirts of an American town. It's two stories high, has seven rooms, and "would have cost perhaps fifteen thousand in the early twenties when it was built" (1.1). It is well-maintained, and communicates visually the material comfort and well-being that the Kellers enjoy.
All My Sons was first produced in 1947, and is set in that period. Men had just returned from World War II; Ann and Chris will have baby boomer kids. Don't forget, either, that all of these characters (except Bert) have lived through the Great Depression. Being poor in the 1930s makes it all the more important for Joe to keep his family comfortable now. Money is not something he takes for granted.