Home is a place, house is a building. It should definitely be replaced to house.
I understand that the plural of "okno" is "okna" but it's not very clear in the translation bubble. Or is it just me?
"Okna" can be either singular genitive, nominative plural, or accusative plural. In this sentence it's accusative plural.
I guess it's because Duolingo expects you to have literal translations whenever it makes sense.