For single room cooling, a window air conditioner offers the best overall value for the price. This is a matter of physics more than anything else. Because the heat exchange is directly from one side of the wall to the other, air movement is minimized, as well as coolant movement. Unlike portable systems, which have to push air several feet, or split units which have to pump refrigerant, a window unit is self contained. This makes it easier to manufacture, ship, and install – all of which makes this choice less expensive.
Operating costs can be higher, because units are “all or none.” They do not have the ability to adjust cooling to meet changing loads quickly, nor do they have the most efficient air exchange over hot coils. SEER ratings, which are used to measure operating costs, range from 13 (the current minimum standard) to as high as 23 for super-efficient central air systems. When possible, it is advantageous to purchase a window unit with a higher SEER rating. This is because a typical window air conditioner will have a service life of 10 to 15 years and with a 4 to 6 month use every year, the savings add up to more than the additional cost.1 There is an additional reason as well – periodic tax credits given for upgrading an existing unit to an Energy Star, high SEER rated unit. For smaller units (10,000 or less BTU) the best value still comes in at a SEER of 13 for most consumers at current electricity rates.2
The next consideration is the size of the area you wish to cool. Although the rule of thumb is, “larger is better” when it comes to cooling capacity, a window unit that is too large will not reduce humidity well and this reduces cooling efficiency. In general, select a window air conditioner that will work in the largest room you may install it in. The general rule is to get 20 BTU of cooling capacity for each square foot in the area you wish to cool.
This figure will have to be adjusted upward if the room is sunny (or even on the south side of a house) or if it has high ceilings (over the standard 8ft). Running a smaller air conditioner may actually be more efficient because it can run consistently, when a larger unit will cycle between on and off as the temperature swings up and down. For this reason, the correct sizing is important – if you are in doubt, ask an HVAC technician to give you an opinion.
Once you have a size range (in BTU) in mind, you will find a variety of pricing options. Prices do vary by cooling capacity, but they also vary with features for the same size units.
Common features include variable fan speeds, remote temperature settings, fan only and dehumidifying capabilities, air filtration and time of day settings. For larger units used in bigger rooms, variable and rotating fans are worth having to avoid cool/hot spots. A remote thermostat is important if the unit is used as a “set-it and forget-it” application but not as important if someone will be present to adjust the temperature to their own comfort level.
After capacity and features, another consideration is the available warranty. When purchasing a more expensive unit ($300 or more) this is an important issue and you want to compare not only what is covered by the manufacturer, but who will handle any repairs and if there are additional fees.
Units range in price from a low of $100 up to about $700 for the largest practical size.
It may be surprising, but there is no clear brand winner with window air conditioners. Competition is fierce in the US market (although all air conditioners are manufactured overseas) and quality is generally very good. The Internet is not a very helpful resource either, because savvy marketers have flooded the net with sites dedicated to pushing the quality of their own products and posting suspicious ratings and reviews. One example is the official sounding, “ConsumerSearch.com” where the top five air conditioners in their review are all Kenmore – it’s pretty obvious they have a bias.3 The situation is made worse when one customer has a problem and spreads their complaint around – giving a false impression that a whole line is faulty.
For this reason, allowing for size and features you need, purchasing from a reputable store is as important as the brand you buy. Certainly you should shop recognizable names like Kenmore, Frigidaire and Friedrich, but you should also know that the name on a product doesn’t necessarily mean it was manufactured by that company.
If you wish to minimize risk and get the latest information, it may be worthwhile to pay the $5.95 for a one month access to consumer reports. This is the most reliable and trusted source on the net for comparison shopping. 4
Features to avoid
Because adding electronic tricks is a low cost option for manufacturers, you will find many little add-ons that do not add much to the basic functionality or value. These tend to clutter up the features list. Some are actually less beneficial than they appear. For instance, an “energy savings” feature that shuts off both the compressor and fan (saving electricity) prevent the natural cooling and air movement you get by leaving the fan running when the compressor is off. Letting the fan run will allow you to set the thermostat a degree or two cooler than when you use the energy savings feature, saving more energy than using the feature does.
Another feature that really isn’t is the “sleep mode” touted as a cost saver when an air conditioner is used in a bedroom. Sleep studies show that we sleep better at a temperature of around 68 degrees, so letting the room temperature rise with the sleep mode feature might interfere with sleep.
Window air conditioners come in a variety of shapes and sizes to fit different window openings. Larger units may need special brackets for support and ease of installation should be considered. If you need a professional installation, this will add considerably to your costs. Will the unit remain in place over winter? In most applications, window air conditioners are removed because of heat loss in the winter. Two smaller units might actually be a better choice than a single monster.
Remember that power supply might be an issue, especially with higher capacity air conditioners. Even those that run on 115 volts may still require a dedicated circuit when they draw 15 amps or more. You should understand power needs and the outlets available where you intend to install the unit. Very large units may require rewiring to give a 220 volt supply.
The number one complaint with window air conditioners, other than reliability, is noise. If a window unit will be installed in a bedroom or an area without background noise, it will be worthwhile to spend more to get a quieter unit. Manufacturers who invest in better sound insulation will advertise the dB, or decibel level of their products – lower is better here. However, even the quietest units will be noisier when they are not installed properly. The air conditioner will vibrate if it is not securely mounted, so a good fit and solid support are a must.