Complex sentence: Rent in basement apartments is usually much lower than in above-ground apartments, in part because the apartments are usually cramped, and in part because they tend to be noisy, both from uninsulated building noises and from traffic on the adjacent street.
Split into simpler sentences: Rent in basement apartments is usually much lower than in above-ground apartments, due to a number of deficiencies common to basement apartments. The apartments are usually cramped, and tend to be noisy, both from uninsulated building noises and from traffic on the adjacent street.