We’ve always liked Hotpads. It’s a scrappy startup that often innovates. It was an early pioneer of real estate heat maps, and more recently added a “Buy vs. Rent” search feature where users can search homes to rent or purchase at the same time and compare them based on monthly costs.

The latest addition is a “vacation” tab which lets users search for around 20,000 vacation home rentals across the U.S. Search results can be sorted by price and availability, which show up when you hover your mouse over any given house icon. All properties are shown on a large map which is the center of the Hotpads interface.

Hotpads, launched in 2005, originally covered only rentals. It added for sale listings in late 2007. The site now lists 3 million homes for sale and 300,000 rentals.

Its entry into the vacation rentals market places it as a competitor – albeit a rather small one – to market leader HomeAway.com as well as Web site Ravant.com.