The Cost of an Extra Bedroom

The Cost of an Extra Bedroom

  • 01/18/16
Question: What is the price per bedroom ($/BR) in Arlington?
This is a GREAT question and I’ve been looking forward to answering since early December. Before I jump into the data, I want to point out that giving a dollar-value is impossible on such a large scale because $/BR is relative to the cost/type of home, so instead of a dollar value, I discuss the % increase to add a bedroom in order to normalize the data.

Cost of a Condo Bedroom

I compared one and two-bedroom condo sales within high rises with at least thirty sales since 2008 and a healthy balance of one and two-bedroom sales. Thirty-nine buildings made the cut, with 1,748 one-bedroom and 1,616 two-bedroom sales representing the data. Instead of lumping all one and two-bedrooms together and taking the average, I calculated % difference within each building first and averaged them together (thank god for pivot tables!).


  • The average two-bedroom condo costs 52.6% more than a comparable one-bedroom (standard deviation of 16.6%)

  • 88% of the time a second bedroom also comes with a second bathroom

  • The average two-bedroom condo is 421 square feet larger than a one-bedroom

  • The cheapest buildings to add a bedroom are Ballston 880 in VA Square/Ballston (16.1% increase) and Tower Villas in VA Square (20.4% increase)

  • The most expensive buildings to add a bedroom are Waterview in Rosslyn (81.8%) and Horizon House in Pentagon City (83.8%)

  • The relative cost to add a bedroom was almost identical in North and South Arlington, although the dollar value increases significantly in North Arlington

Cost of a Detached/Single Family Home Bedroom

I chose to compare Craftsman style homes because they’re the most popular home design in Arlington right now and are mostly newer builds/renovations with similar quality (good for data). In all, there have been 495 Craftsman-style homes sold in Arlington in the last 10 years. 94% of those sales were for three, four, or five-bedroom homes (22%, 56%, and 16% respectively), so this is where we’ll focus.


  • Adding a fourth bedroom costs an average of 28.5% more than a comparable three-bedroom

  • Adding a fifth bedroom costs and average of 10.5% more than a comparable four-bedroom

  • The cost difference closely tracks the increase in square footage, with a 22.6% and 7.3% increase in square footage between three and four-bedroom and four and five-bedroom homes, respectively

  • The 22201, 22205, and 22207 zip codes were responsible for 82% of the total Craftsman sales volume (last 10 years) with average sale prices of $1.16M, $1.43M, and $1.56M for three, four, and five-bedroom homes, respectively
I also found that the relative cost to add a bedroom remained consistent over the last 10 years, despite the dollar value increasing as home prices go up.
ATTN Readers!! In March I’m starting a monthly neighborhood spotlight and looking for Arlingtonians who would like their opinions incorporated into this column (favorite running trail, best neighborhood bar, neighborhood personality, etc). Send me an email if you’re interested!


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