Why Google ratings can't tell you which contractor to hire
What is the average Google rating for plumbers, roofers and HVAC contractors?
Across 134,778 rated US home-services businesses, the mean Google rating is 4.62 for plumbers, 4.68 for HVAC contractors and 4.73 for roofers. Between 52.7% and 63.0% of each trade sits at 4.9 stars or above, on a median of roughly 20 reviews. The ratings are compressed so far into the top of the scale that they barely separate anyone.
Measured across our HVAC, plumbers and roofers files, 156,415 businesses in total, built 24 July 2026 from Google Maps listings. These are the only three files in our local set that carry review counts and ratings, which is why the report covers three trades rather than 27.
A business counts as rated only if it has at least one review and a rating above zero. Google reports an unrated business as 0, and averaging those in would drag every trade down and make the number meaningless. 134,778 of 156,415 businesses, 86.2%, are rated on that definition, and every figure below is a share of the rated subset, not of the file.
The HVAC file is the weakest in our catalogue on completeness generally, so its 78.9% rated share is partly a data-coverage artefact rather than a statement about HVAC contractors. Plumbers at 92.1% and roofers at 93.5% are the more reliable readings.
The three trades
Rated businesses only. Measured 24 July 2026.
| Trade | Rated businesses | Mean rating | 4.9 stars or above | Below 4.0 | Median reviews |
|---|---|---|---|---|---|
| Roofers | 30,003 | 4.73 | 63.0% | 6.4% | 20 |
| HVAC | 58,071 | 4.68 | 57.6% | 8.2% | 23 |
| Plumbers | 46,704 | 4.62 | 52.7% | 10.0% | 22 |
A five-point scale being used as a one-point scale
The entire usable range of these ratings is about 4.4 to 5.0. More than half of every trade is at 4.9 or above, and fewer than one in ten is below 4.0. The bottom three quarters of the scale is almost empty.
That means a 4.8 rating is not a good score, it is a below-median score. A homeowner comparing three roofers at 4.7, 4.8 and 4.9 is reading noise, and a business owner agonising over a single one-star review is responding to something that moves a number nobody can interpret.
And the sample sizes are tiny
The median rated business in these trades has around 20 reviews: 23 for HVAC, 22 for plumbers, 20 for roofers. Half have fewer.
A 4.9 average from 20 reviews means roughly two people were unhappy. Move one review and the rating shifts by a tenth, which on a scale this compressed is the difference between above and below median for the whole trade. The rating is not measuring quality at that sample size; it is measuring luck and how hard the owner chases reviews.
If you are selecting or scoring contractors at scale, review count is the more informative field, and it is the one almost nobody sorts on.