What is a good duplex comparable sale?
A useful comparable is a recent sale that competes for the same buyers and is reasonably similar in legal use, location, unit configuration, size, condition, lot, parking, utilities, occupancy, and rental profile.
Start with legal and physical similarity
- Confirmed two-unit or comparable legal use
- Similar market area and buyer pool
- Comparable total and per-unit living area
- Similar bedroom and bathroom mix
- Comparable lot utility, access, privacy, and parking
- Similar age, condition, renovations, and deferred maintenance
- Comparable utility responsibility and metering
Then compare the income profile
Current rent, market-rent potential, vacancy, lease terms, concessions, and owner-paid expenses can change how investors perceive two otherwise similar duplexes. Owner-occupant appeal may also matter when one unit is vacant, larger, or substantially more attractive.
Why the nearest sale is not always the best sale
Proximity matters, but the closest sale may be a poor indicator if it has different legal status, unit mix, condition, rent, or buyer appeal. Fannie Mae’s current guidance says comparable sales should have similar physical and legal characteristics and should compete for the same market participants.
Common duplex adjustments
| Difference | Question to investigate |
|---|---|
| Condition | How did buyers in this market react to renovated versus dated duplexes? |
| Rent | Were the rents verified, below market, or affected by concessions? |
| Utilities | Which utilities are separately metered or owner paid? |
| Occupancy | Did vacancy improve owner-occupant appeal or signal income interruption? |
| Parking | Is parking functionally comparable for both units? |
| Sale terms | Were there concessions, unusual financing, or non-market motivations? |
What if there are few duplex sales?
The search may need to expand in time or geography, but every expansion introduces new differences. Those differences should be explained and supported. A single-family sale does not automatically become a good duplex comparable merely because it is nearby.
Comparable selection example
A duplex two miles away with similar unit sizes, legal use, rents, and condition may be more informative than a property two blocks away that was converted without clear permits, has one substantially smaller unit, and includes unusual seller financing.
Authoritative references
Review Fannie Mae’s comparable-sales guidance and its discussion of market-supported adjustments. Then compare the results with the income-based calculator.