In many cases, it is the aroma . Perhaps the one living in the home is not in the best position to answer this question.
Aromas are the sorts of things one gets used to.
The residents usually do not notice those things that immediately strike a visitor. So if there is an offensive aroma in the home, it can sometimes be a difficult problem to solve. No easy formula of resolution is available. Nevertheless, the Bible does teach on the subject. The text noted above says that when Christians walk in love they are imitating Christ, and the sacrifice of Christ is a pleasant aroma to God.