But household is not the same as house! 'Household' would normally refer to the people living in the house and 'house' to the building itself. I can think of examples where the words house be used to refer to the people with the appropriate context, but this would not be most obvious usage of the word.
Well, then, if it's being used in that very specific context that you would use household, house would then be wrong. For example, if you're saying "Name everyone in your household," it would not be interchangeable with "house," since often times children off at college or boarding school are still part of the household, but not living in the house. Same for spouses/parents that are currently living elsewhere for work reasons, etc.
Also, "name everyone in your house" would literally mean everyone currently in your house, not just the people living there, and would not include people who live there but are not currently present.
I'm not sure what is actually meant by "This household is perfect". Is it referring to the condition of the furnishings? Or the relationships of the people? Or the census count? My frame of reference is that "household" is a word used by everyone in the US every year, when everyone does their taxes. Head of household is a single person responsible for several dependents in a house, whether they're actually living there or not. A dependent child could be away at school, and a dependent parent could be in a nursing home. But if the taxpayer supports them, they're still part of the household. So "household", in my opinion, refers to a collective group of people, living together, with all their belongings, who are dependent upon the master of the house. It doesn't mean the house per se. So, back to my original question, is Haushalt used in the same way in German as household is in English? And where does perfection come in?
@Jumap : 'der Haushalt' is masculine singular, and in this sentence the nominative case is used, so dieser must be used. Take a look at the table in the following link: http://www.canoo.net/inflection/dieser:Pron:Demonstr
If you say "This is a (noun)." you use "das". If you say "This (noun) is (...whatever you like...) you use "dieser", "dieses", "diese" depending on the gender of the noun. Or maybe "der", "die", "das" which would mean "the", but it's almost the same. The word before the noun should be in the same gender. If you say "das (noun)" then "das" means "the", not "this", and it's used only with neuter nouns.