Portable Air Conditioner Buying Guide

Understanding portable air conditioners

A portable air conditioner, also known as a room air conditioner, is a self-contained unit that provides cooling. Like window and wall models, portable air conditioners cool by using a fan to draw air past a coil filled with pressurized refrigerant gas. As the air passes the coil, hot air is pulled out and replaced with cold air.

For a portable air conditioner to be effective, hot air must be vented outside of a sealed room. Most portables have a vent hose that installs in a window to push out hot air. It’s best to take the term “portable” with a grain of salt; portable air conditioners can weigh from 50 to 90 pounds, but these self-contained units move on casters, making it easy to push them from room to room.

Portable air conditioners are not as effective at general cooling as window- or wall-mounted air conditioners, typically because they’re the only source of cooling in a hot home. If you live in an apartment, have windows that prevent the installation of an air conditioner or have hot spots in a home with central cooling, you’ll benefit the most from a portable air conditioner. If you need significant cooling, check out Pronto’s Air Conditioner Buying Guide.

Portable air conditioner ratings

All air conditioners are rated for cooling in terms of British Thermal Units (BTUs) per hour. A single BTU is a measurement of a portable air conditioner’s ability to lower the temperature of a pound of water by one degree Farenheit. More BTUs equals more cooling power, but also more energy consumption.

To determine the amount of cooling needed, you should convert BTUs to tons at a rate of 12,000 BTUs per ton. In other words, a 12,000 BTU air conditioner creates one ton of cold air per hour, enough to cool a 500-square-foot room. If you’re using a portable air conditioner to supplement cooling from a central system, you can stick with this standard measurements. But if the portable air conditioner is working alone, either in an apartment or a home that lacks other air conditioning, you’ll need 20% to 30% more BTUs per 500 square feet for effective cooling.

There are many variables to consider in choosing the power of a portable air conditioner. Consider the room size, its location in the house (heat rises, so you’ll need more cooling on upper floors), insulation thickness and the quality of window seals. Ceiling height also plays a factor, as BTU and ton ratings assume a standard eight-foot ceiling. When it comes to portable air conditioners, it’s a good idea to get more than the minimum needed for the best cooling.

Cooling controls

Gone are the days of twisting a knob all the way to the right for maximum cold. Most portable air conditioners now offer digital controls that let you set a precise temperature, a feature worth paying for because it gives you precise climate control and regulates energy consumption. Some portable air conditioners include remote controls, so you don’t have to break a sweat walking across the room to make adjustments.

Adjustable fan speeds are another feature that adds to the efficiency of portable air conditioners. Most portables offer two or three fan speeds and few manufacturers charge more for this feature. A little comparison shopping will yield a portable air conditioner with the fan settings you desire.

Variable fan speeds also let you control noise, which is a chief concern if you’ll be using a portable air conditioner where you sleep. Portable air conditioners bring all the cooling elements into the room, making it worthwhile to read online comments about noise when you’re shopping.

Condensation and filters

When hot air meets cold air, condensation occurs, creating water. Most portable air conditioners need a way to get rid of condensation, though some newer models can evaporate the water they create. Known as evaporating or dripless portable air conditioners, these models come at premium prices but may be worth it for ease of use.

Most portable air conditioners collect condensation in a drip pan that must be removed and emptied on a regular basis. Look for deep drip pans that slide out easily to prevent spills and eliminate the need for 3 AM emptying on hot nights.

Alternatively, you can choose a portable air conditioner that disposes of water through its vent hose. Although this feature eliminates the need to empty drip pans, it limits the placement of the portable air conditioner as you’ll need the hose to have a short downhill trip outdoors to prevent water from collecting in the hose.

Portable air conditioners have filters that prevent dust and other airborne particles from clogging their fans. Most filters are for the portable air conditioner’s benefit—they won’t clean the air, they just keep dust from clogging moving parts. Some portables can use air-cleaning filters, but if clean air is a top concern, you’re usually better off with a separate air filtration system.

Filters need to be cleaned or replaced periodically. The best value is a portable air conditioner with a reusable filter that can be removed, cleaned and replaced. This provides a lower lifetime ownership cost than a portable air conditioner with disposable filters.

Energy savings

Most people think of air conditioners as electricity hogs. In reality, a portable air conditioner can reduce your energy use by cutting back on whole-home cooling. Portable air conditioners let you turn the main thermostat up while keeping cool in a single room.

To get the best balance of electricity consumption and cooling, look at a portable air conditioner’s energy efficiency rating (EER), which divides a unit’s BTUs per hour by the amount of electricity consumed. Higher EERs deliver more energy efficiency. A portable air conditioner with an Energy Star certification is at least 10 times more efficient than comparable models. Remember, too, that raising the thermostat and slowing down the fan will provide the greatest energy efficiency.

Need to know more?

• Portable Air Conditioners FAQ
  http://www.sylvane.com/FAQS/portable-ac-faq.html
• Energy Star Qualified Room Air Conditioners
  http://www.energystar.gov/index.cfm?c=roomac.pr_room_ac
• Air Conditioner Sizes and Features
  http://www.goodhousekeeping.com/home/products/air-conditioner-faq-1001_2