How the score works.
Each home's score adds up points for signals on the public record: a recent sale, a named AC install past its warranty, the assessed improvement value, and how many permits were pulled before. Every home shows the lines that produced its score.
Signals
The signals and their points.
| Signal | Points | Where it comes from |
|---|---|---|
| Sold in the last six months | +25 | Sale date on the Clark County Assessor record |
| Sold in the last year | +15 | Sale date on the Assessor record |
| Sold in the last two years | +6 | Sale date on the Assessor record |
| Named install past its warranty | +8 | Installer and install year on the City permit record |
| Assessed improvement value | up to +25 | Assessor improvement value |
| Permits pulled before | up to +10 | Count of earlier permits on the City record |
Testing
What the score has been checked against.
The score is being backtested against permits filed later: for homes in each score tier, how often a new AC permit was filed within four years. Tier rates are not published yet. For comparison, a random Las Vegas home had a new AC permit filed within four years 7.6 percent of the time.
Where the data comes from
City of Las Vegas building permit records, matched to the Clark County Assessor parcel file on the street address. A permit names the company that pulled it and the date. Companies change legal entity and keep trading, so an old installer name says nothing about whether that company is still in business.
What the score cannot see
Roughly one in three to one in five replacements leaves a permit at all. Homes with no AC permit on record are not on the list, and the score never guesses an age from the year a house was built.