Trulia's rental map is based on our rental listings over the last year. The map updates monthly so that we always have the most up-to-date view of current rental price trends. Rental price data are summarized by U.S. Census block groups, zip codes, or counties, depending on the zoom level. This procedure makes it easy for our audience to visualize the economic geography of most areas of the country that have rentals.
The median price per bedroom measure shows how much someone should expect to pay for an apartment of any given size or number of bedrooms. Users can quickly calculate how much they'd expect to pay for a 1, 2, 3, or 4+ bedroom apartment for a given area, though it should be noted that there is a non-linear relationship between price and number of bedrooms. For example, in an area with a median value of $1000 per bedroom, a 1-bedroom apartment is likely to cost a little more than $1000, and a 4-bedroom apartment is likely to cost a little less than $4000. In the future, we plan to update this map using a measure of median price per square foot, as the data becomes available.
While this is a national map, we do not have full coverage for every location. In time, we expect to expand our coverage as new rental listings are added.