Every parking air conditioner gets a score from 0 to 100% built from five 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. Units are grouped as 12 V split, 24 V split and under-dash.
| Factor | Measures | Weight |
|---|---|---|
| Value | price per 1,000 BTU of credited cooling | 35% |
| Efficiency | claimed BTU per watt of input | 20% |
| Noise | listed sound level of the indoor unit | 15% |
| Features | inverter, remote, ships charged, low-voltage cutoff | 20% |
| Warranty | warranty on the unit | 10% |
Where the numbers come from
Almost every figure is the seller’s own listing copy at Amazon, because the sellers publish no spec sheet or manual. That means every BTU rating is a claim, not a measurement, and no independent testing of these units has been published. Prices are the Amazon price when we checked.
The factors
Value is the current price divided by credited cooling, per 1,000 BTU, on a log scale: $80 scores zero and $25 full marks. Claimed cooling is credited only up to 11 BTU per watt of rated input power. A listing that claims 12,000 BTU on 800 W is credited 8,800 BTU. When no input power is published the claim can’t be checked, so it is credited only up to 10,000 BTU.
Efficiency is the claimed BTU divided by rated input watts: 6 BTU per watt scores zero and 11 full marks. A ratio above 12 is noted on the product page as above what a battery compressor delivers and earns no more. Units with no input power published get the neutral middle score, marked estimated.
Noise is the sound level the listing gives for the indoor unit: 65 dB scores zero and 40 dB full marks. Sellers rarely say how far away or at what fan speed it was measured. Units with no rating get the neutral middle score.
Features is a count of four things the listing names: an inverter (variable-frequency) compressor, a remote control, refrigerant already charged in the unit, and a low-voltage cutoff that stops the unit before it drains the battery. Each is worth a quarter. A feature the listing doesn’t mention is not credited, and the product page marks the score estimated.
Warranty is the warranty on the unit: no warranty scores zero and 2 years full marks. Most listings state none, so most units score zero, marked estimated.
What isn’t scored
Heating, compressor size, airflow, starting current, voltage and layout are listed but not scored. Rooftop 12 V RV units are ranked under RV Air Conditioners and battery-powered portables are a separate category.
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: no published warranty is scored as none.
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.