To test portable air conditioners, we waited until the sweltering summer months — or at least as sweltering as it got at our latitudes — then researched over 50 different models to pick the most promising candidates and bought them to test side-by-side. This article breaks down exactly what we did to test and score each product, determining which ones are worthy of our awards. If you are interested in how specific products perform, consult our comprehensive Portable Air Conditioner Review or head on over to our Buying Advice guide for more background on these products and what to check for when shopping for a new one.
For our Cooling Power metric, we scored each A/C on how much it could drop the temperature of a warm room in 60 minutes. This is the primary function of these products, so it constitutes 40% of the total score for each product. We only tested one unit each day, ensuring that the outside temperature and amount of sunlight entering the room were comparable for each test. Ideally, we were looking for direct sunlight and an outside temperature in the mid-80s.
To start, we picked out a 161 square foot room — comparable to a small to medium bedroom as our testing room, then heated it as much as we could with a small army of space heaters. We got the temperature as high as we could, then gave it a small amount of time to settle to a stable temperature, so we didn't artificially inflate the cooling performance of each product.
We then ran each product on its highest cooling mode for an hour, taking the ambient room temperature every 20 minutes with a lab-grade thermometer placed to measure the average temperature of the room, out of the way of direct sunlight or airflow from the AC unit.
A key feature of these products is the ability to move them somewhat easily to the rooms where you most need cooling or the ability to store them during the colder months. Thus, our Portability metric accounts for 25% of the total score for each product.
These products have wheels, so we started by evaluating and judging how easy it is to roll each of these appliances around. We looked at both the rolling resistance and maneuverability of each one to score them, though we did omit carrying the hose and window insert while testing this.
Next, we compared the weight of each unit, as well as the ergonomics of the handle to judge how hard it is to carry each of these models — a must if you live in a multi-level dwelling and want to move the A/C between floors.
Finally, we ranked each product on how easy moving the window insert between different windows is. This included the time it took to remove and install it, how difficult those processes are, and any tools required to complete them.
Cooling down your bedroom to make it easier to sleep comfortably is relatively useless if the cooling unit is so noisy that it makes it impossible to sleep. Our Noise metric accounts for 20% of the total score and is based on two separate tests. First, we measured the objective noise with our SPL meter, both right at the loudest part of the machine and at a distance of about 4' away. We did this test on each AC unit's low, medium, and high setting — if it had all three of those. We awarded the most points to the quieter models and the fewest to the noisy ones.
Second, we had a handful of judges listen to each air conditioner on its highest setting and rate their noise level in terms of annoyance. This test was primarily to look for any particularly irritating tones, like a high-pitched whine, that wouldn't necessarily be captured by the SPL meter and aggregated their survey results to determine the scores.
For our final rating metric, worth the remaining 10% of the score, we evaluated how much energy each model consumes. Having a cool room on a hot summer day is great, but it's no fun at all if it ends up blowing a huge hole in your budget by running up an exorbitant power bill.
We did this by measuring the actual power consumption of each A/C unit using a wattmeter on both their lowest and highest settings for 30 minutes in comparable ambient conditions, then using our measurements to determine the average power consumption — in Kilowatt-hours (kWh) — for each unit on both settings.
We then assumed that you run each A/C for 2 hours on high when you first get home to cool the room, then drop it to low to keep it cool for the next 10 hours, every day of the summer. This gave us the total amount of Kilowatts consumed, which we multiplied by the average electricity cost to get a rough idea of how much each costs to run per year.
This won't apply to everyone, as everyone has their personal preferences on indoor temperature, different electricity prices, and the percentage of the year that an A/C unit is required. However, the relative ranking of these products will stay the same, even though our estimated annual cost may differ for you.
Hopefully, this guide should make it a bit more clear how we sorted through the dozens of different air conditioners out there to pick the most promising and what went into selecting our award winners. If you want to read more about the A/C units we tested or are struggling to pick the perfect model, check out our comprehensive review of the best products on the market today and our Buying Advice article.