The Summer Rental Rat Race

“You had a brochure you printed out on your dot-matrix printer and you mailed it out to people and they booked,” recalled Mr. Johnston, who lives on the Upper West Side. “The season lasted from May until October, and I would get 15 weeks rented.”

But as more vacation-home owners have entered the rental business, with help from a growing collection of Web sites that make it easy to post listings, the competition to attract tenants has become fierce. Though Mr. Johnston has upgraded his kitchen with a Bosch dishwasher and an Italian coffee maker, adding a terrace and building a Web site to market his home, he has had few renters in recent years.

“My rental business has disappeared completely,” Mr. Johnston said. “Last summer I had one renter, this summer I have none.”

He admits he is not willing to drop his price — about $900 per week — to compete with neighbors charging much less, and he does not market his house aggressively because he paid off his mortgage. But his experience is a cautionary tale for anyone thinking about taking the plunge.

“Real estate agents who want to sell you a house will tell you that you can make money off it,” Mr. Johnston said. “Well, I did 20 years ago, but I don’t anymore.”

There is often money to be made in vacation homes, but as the number of listing services has increased, so have the number of properties posted for rent. For example, HomeAway.com, one of the most popular sites, says it has more than 300,000 rentals worldwide.

Numbers like that are forcing casual landlords to learn how to make their homes appear higher in search results, to track prices by monitoring their neighbors’ listings, and to deal with customer-service headaches like a negative Yelp-style review from renters.

A co-owner of a rental house near the Catskills, speaking anonymously in order to avoid trouble with future renters, said: “We had a couple who did some damage to the house, and when we told them about it they said that it wasn’t them. We decided it was better to eat the $150 repair rather than risk having a bad review.”

This homeowner said the number of houses for rent in her community had doubled in the past five years, giving potential renters more options — and more incentive to haggle over the price. “The other day I quoted $1,850 for a week in July,” she said, “and the most one guy would pay was $1,250. Now, if someone makes an inquiry it often doesn’t turn into a rental.”

HomeAway listed 304 homes for rent in the Catskills in 2008; now it has roughly 520 homes available. Along the Jersey Shore over the same time frame, listings increased to 2,200 from about 700; in the Hamptons they jumped to 750 from 270.

HomeAway owns another popular Web site, VRBO, which stands for “vacation rentals by owner.” But at these and other HomeAway sites, homes posted by professional property managers now account for 27 percent of the listings.

“We see that as a net benefit for our travelers,” said Jon Gray, HomeAway’s vice president for North America. “It gives more choice to them.”

It also creates more competition for individual homeowners, who themselves have more rental listing services to choose from. The options include global players like HomeAway and FlipKey, which is owned by TripAdvisor, and specialized sites like Gite.com, which lists holiday homes in France.

FlipKey charges $299.99 a year to list a home for rent, with a 60-day free trial. HomeAway charges $329 a year for a basic listing, but is shifting to a tiered pricing system with more options for additional fees.

Customers who upgrade to a “bronze level” membership ($429 a year) appear in the search results above the listings in the lowest tier. The highest level, “platinum” ($999 a year), offers a top ranking in the search results and rotating promotion as a “featured rental.”

Gary Gilbert lives in Boston with his wife, Donna Brezinski. The couple own two rental houses in Provincetown, and tried upgrading one of their HomeAway listings to the “gold” level (just below platinum) earlier this year. That increased the number of people who viewed the house by about a third, he said, but the impact on bookings was less clear.