Every home energy monitor gets a score from 0 to 100% built from six factors, which maps onto the 5-point rating shown on the site (a 0% score would be 1.5 stars; a perfect score, 5). Each factor is scored against fixed reference points, not against the other products in the list, so adding a new model never moves another model’s rating. Monitors are grouped as circuit-level (8 or more branch sensors included) or whole-home, and use the same scale in both groups.
| Factor | Measures | Weight |
|---|---|---|
| Value | purchase price | 25% |
| Circuits | branch circuits in the box, plus half of any that can be added | 20% |
| Local control | local API, MQTT or hub, Home Assistant, and working without the cloud | 20% |
| Accuracy | maker's claimed accuracy, not independently measured | 15% |
| Subscription | whether the maker says the service is free | 10% |
| Warranty | warranty length | 10% |
Where the numbers come from
Circuit counts, sensor ratings, supported systems, accuracy, connectivity and warranty come from the maker’s listing or manual, including the maker’s own copy on a retail listing. Where one listing contradicts another for the same model, we say so on the product page or leave the figure out. Accuracy figures are the makers’ claims; we have not found independent measurements. Prices are checked at Amazon and the lowest price at a store the page links to is used.
The factors
Value is the purchase price on a log scale, so halving the price always counts the same. $350 scores zero and $60 full marks.
Circuits is the number of branch circuits in the box, plus half of any that can be added later: 0 scores zero and 16 full marks. A mains-only monitor scores zero here, which is why whole-home monitors are ranked separately.
Local control is 60% for a local API, MQTT, scripting or hub that works without the maker cloud, 30% for Home Assistant support the listing names, and 10% for working without the cloud. A monitor that needs the maker’s cloud app scores zero.
Accuracy is the claimed accuracy: within 3% scores zero and within 1% full marks. It is not independently measured.
Subscription is full marks when the maker says there is no subscription, and zero if one is required.
Warranty is the maker’s warranty: 1 year scores zero and 5 years full marks.
What isn’t scored
Mains and branch sensor ratings, supported phases, solar support, connectivity and release date are listed but not scored.
Missing data
If a figure isn’t published, that factor gets the neutral middle score (50) and the product page marks it as estimated. The exception is warranty: a maker that doesn’t publish one gets no warranty counted, so that factor scores zero, the same as a one-year warranty, and is marked estimated.
Ties and discontinued models
Products are ranked by score within each group. Discontinued models stay listed but rank below every current model and can be hidden with the “Hide discontinued” filter.