room air conditioners

Room air conditioners – also called window air conditioners - are conceived to cool just one room. With room AC we may restrict the use of the equipment to the needs of a specific room (zoning), achieving considerable cooling savings over central air conditioning.

Energy Efficiency of Room Air Conditioners

The efficiency of a room AC is measured by its EER (Energy Efficiency Ratio) rating. The EER is the relation between the cooling capacity and the watts power input, which makes an high EER a good indicator. Replacing an old room AC with a EER of 6 with a 12 EER one will reduce air conditioning by half.

So, do not buy room ACe with low EER ratings. Buy equipments with an EER of at least 12. Also look for AC units with UE eco-labeling (for European countries) or the Energy Star ratings (in USA, Canada or New Zealand and Australia).

Installing and Operating Your Room Air Conditioner

Little details when installing a room AC can save you electricity (and money):

- Level the equipment: equipments with inside mechanisms (namely the drainage system…) unleveled will not operate efficiently;

- Install the equipment in a shaded spot, whenever possible. In the north hemisphere, the home's north and east side are the best ones (in the south hemisphere, install the room AC at the opposite sides). The main rule is to avoid as much as possible direct sunshine on the unit's outdoor elements.

- If possible, have or plant trees and shrubs to shade the air conditioner (without blocking the equipment airflow);

- Never place lamps or televisions near the AC thermostat; the heat from these or other appliances will cause the air conditioner to run longer and… unnecessarily.

Where to install the room AC unit

Installing the room AC unit in a central position is usually a good option.

If you intend to install near a corner, look for units that can drive their airflow into the remaining room.

If you need to install the room AC at one extreme of a long room, look for a fan control to send the cooled air into the whole room (the so called "Power Thrust" or "Super Thrust" control fans).

Room Air Conditioners and electrical circuits

Smaller room AC – demanding less than 7.5 amps of electricity, can be plugged into common household circuits (if they aren’t shared with other demanding appliances). Larger room AC (more than 7.5 amps) may require dedicated 115-volt circuits or even dedicated 230-volt circuits.

Thermostat use

You will not get a faster cooling by adjusting your thermostat to a very cold setting. A normal setting will cool your home as fast as a colder one. A colder setting will represent an excessive cooling and higher bills.

Other tips concerning Room AC

- Prefer a room AC with a digital readout for the thermostat setting, and a built-in timer.

- In high humidity days, set the AC fan speed on low. It will cool your home better and it will dehumidify more, due to slower air movement through the cooling equipment;

- Using a fan in conjunction with room AC is often a good option: it will spread the air very effectively with low costs (the electric consumption of fans is very low).

- Do not oversize (or undersize) your room AC (see: Air Conditioner Sizing)