Room Air Conditioners
Purchasing Considerations
- Energy efficiency
- List of models: Room air conditioners
- The right size
- Installation
- Operating costs
- Life expectancy and warranties
Components of a Room Air Conditioner
Energy Efficiency
The efficiency of room air conditioners in converting electricity into cooling effect varies widely, depending on the manufacturer's design choices.
With room air conditioners the bold number shown on the EnerGuide label represents the energy efficiency ratio (EER) of the unit. The higher the number, the more energy efficient the model. Models for window mounting are available with an energy efficiency ratio (EER) between 12.0 and 8.0; the EER of units intended for through-the-wall applications ranges between 9.5 and 8.0.
An ENERGY STAR® qualified window-mounted room air conditioner with a cooling capacity under 20 000 Btu/h must have an EER rating of at least 10.7.
High-efficiency units generally incorporate efficient rotary compressors, large evaporators and condensers with louvered fins and internally rifled tubes, as well as efficient fans and a slinger ring to deposit water collected from the evaporator onto the hot condenser. Minimum efficiency units tend to use small conventional heat exchangers and standard compressors and fans.
Efficiency of a room air conditioner
While higher efficiency units are more expensive to manufacture, retail prices do not necessarily reflect this premium. Select a unit with as high an EER as is practical, to minimize operating costs.
List of models: Room air conditioners
This list of models is continually updated and indicates which models are sold in Canada along with their energy ratings, including ENERGY STAR qualified models.
The Right Size
Choose an air conditioner with the proper cooling capacity for your application. An oversized unit may not stay on long enough to properly dehumidify the room, and an undersized unit will not be able to handle the cooling load in extremely hot weather.
The amount of cooling that the air conditioner must provide to maintain comfort conditions is called the cooling load. It is affected by such factors as the size of the room, the size and orientation of windows, attic and wall insulation levels, and the amount of heat being generated in the room. As a rough rule of thumb, 200 Btu/h of room air conditioner capacity is required to cool and dehumidify each square metre of living space. Ideally, the unit should be sized by a qualified air conditioning contractor, using detailed calculations that take into account factors such as the size of rooms, insulation levels, size and orientation of windows and doors, shading, number of occupants, appliances, lighting and climate. How to determine the right size.
Installation
Room air conditioners are available in styles that are designed to be mounted either through the wall or in a window opening. There are considerably more window-mounted models available, providing you with a good choice of features and suppliers.
Through-the-wall units offer the advantage of leaving windows available for aesthetic reasons, natural lighting and ventilation, but they do require the construction of a special opening in the wall, which can be costly. This approach lends itself to a tighter installation, so you should consider it if the air conditioner is to be left in place permanently.
While there usually isn't any choice as to the orientation of a room air conditioner, the best location is on a north wall or a wall that is shaded. A northern exposure is ideal, since solar heating of the unit is minimized.
Some room air conditioners can be quite heavy and awkward. Use enough helpers to make the installation a safe one. Once the unit is securely fastened in place, seal up all air leaks to avoid unnecessary air exchange (and cooling load) when the air conditioner is running. Fill large gaps with the panels or side curtains provided in the installation kit. Seal any remaining cracks with either peelable caulking or a sealant strip that stops draughts and can be removed without damaging the paint. An airtight seal will also prevent insects from entering the house through the air conditioner opening.
Room air conditioners usually weigh 25 kilograms or more and can be quite bulky. Consider design features, such as a slide-out chassis, that improve the ease and safety of installation and removal. Removing and storing your air conditioner properly for winter can make the unit last longer and lead to greater savings. Consider the potential heat loss when the unit is removed for the winter. Can the empty space be insulated easily? Most through-the-wall units require experienced installers, whereas smaller, lighter window units are relatively easy to install. A large, heavy unit usually needs a slide-out chassis and outdoor support and may require special electrical circuitry.
Room air conditioners, particularly those with larger capacities, should have a dedicated electrical circuit or have specific requirements regarding the current rating of the wiring and the breaker. Before you buy, investigate your electrical system. Identify which other electrical loads are on the circuit that you plan to use, and have an electrical contractor check existing wiring to determine how much additional load can be safely added. If a new circuit is needed, it should be installed by a qualified electrical contractor and inspected for conformity with the electrical code.
Noise
Noise level inside the room is also an important consideration. Noisy units might cost less but may bother you and your neighbours. Some municipalities have by-laws that establish maximum sound levels. To compare machines accurately, ask the salesperson to run each unit for a minute or two with the fan and compressor operating. Listen closely to the sound generated by the fan (indoor noise) and the compressor (outdoor noise).
Air Circulation
Good control over the direction and distribution of cool air from the unit is also important. Consider whether you need a high-velocity jet of cool air to penetrate well into a large room or if specific regions should avoid cool air. Select a unit with appropriate louver adjustments to fit your needs.
Controls and Energy-saving Modes
You can save both money and energy with such features as a programmable thermostat, a built-in timer or an energy–saving mode, which switches off the fan automatically whenever the compressor motor stops. A remote control can make it easier to save energy if the air conditioner is installed in a hard-to-reach spot.
Operating Costs
The cost of operating a room air conditioner will depend on the cost of electricity in your area, the cooling capacity, the EER of the unit and, most importantly, the amount of time that it operates. Many factors, notably the weather, will significantly influence the number of hours that it runs each year.
NRCan's 2006 EnerGuide Room Air Conditioner Directory includes conversion tables that provide the approximate energy consumption, in kilowatt hours, of different room air conditioners for locations across Canada. You can use these tables to estimate the operating cost for your location, air conditioner capacity and EER rating.
Remember that the way you operate the unit can have a large impact on the actual operating cost: heavily used room air conditioners run for three or four times as many hours as their seldom-used counterparts.
Life Expectancy and Warranties
In general, you can expect a new room air conditioner to have a service life of approximately 10 years. Lower annual run-time results in a greater-than-average life expectancy.
Warranties vary from one manufacturer to another. Some form of five-year warranty is common, with complete parts and labour coverage in the first year. Subsequent coverage is usually limited – for example, to the cost of sealed refrigeration-system parts. Check warranty details before buying.
The ENERGY STAR name and the ENERGY STAR symbol are registered trademarks of the United States Environmental Protection Agency and are used with permission.