The apartment was on a low floor, with plenty of activity outside, including a parking lot and a playground across busy East 132nd Street. “You can hear children screaming with joy through a plate-glass window,” Mr. Murphy said.

Both men work from home, making the noise a problem. “I am there during the day when all that is happening,” he said. The apartment later sold for $622,000.

Elsewhere in Harlem, a two-bedroom in a small, renovated condo was listed at the temptingly low price of $550,000, with monthly charges in the mid-$400s.

“When I got up there, I kind of loved it,” Mr. Murphy said.

The unit had a long, skinny layout with an extra nook for working or dining. But there were several drawbacks, including its location on the top floor of a five-story walk-up. “I have lived in those buildings in the past, but I was younger at the time,” he said.

It also had a monthly assessment of more than $860. “When you climb up and have the sweat running down your neck, they hand you a paper with the financials, and that’s when they tell you about the assessment,” he said. “It was kind of a jaw-dropper.” The apartment later sold for $530,000.

Image A two-bedroom in a small, renovated central Harlem condominium had a long, skinny layout with an extra nook for working or dining. But it was on the top floor of a five-story walk-up and came with a monthly assessment. Credit... Michelle V. Agins/The New York Times

Mr. Balaguer was out of town for most of the hunt, so Mr. Murphy sent him photos as he went. “I could tell he wasn’t really sold on anything and was going to keep looking,” Mr. Balaguer said.