INTRODUCTION

In summer, high relative humidity, elevated air temperatures and bright sunshine can sometimes combine to produce an uncomfortable indoor environment. An air-conditioning system can provide comfort for occupants by lowering the air temperature and the humidity level in the home.

Options that are open to the consumer include a room air conditioner, a central air conditioner or a heat pump. The best choice of system will depend on your circumstances; therefore, it is worthwhile taking the time to evaluate your needs.

Does the whole house need to be air-conditioned or would cooling in one or two rooms be sufficient? Room air conditioners offer an effective, low-cost approach to providing comfort in a small space, up to three rooms, with minimum installation effort. Central air conditioners and heat pumps are used to cool the entire space. Central air conditioners are cooling-only products, whereas heat pumps provide winter heating as well. The cost of a heat pump is greater than that of a central air conditioner, which is greater han that of a room air conditioner. The choice between central air conditioners and heat pumps is examined in Natural Resources Canada's booklet Heating and Cooling with a Heat Pump.

If you are currently renting your home or apartment or if you are planning to move in the near future, a significant investment in either a central air-conditioning system or a heat pump probably does not make sense. However, a room air conditioner can be moved with you and re-installed in another residence.

If your home has a central air-duct system and an acceptable place to mount the outdoor unit (see “Installation considerations”), installation of a central air conditioner or heat pump should be straightforward.

In bungalows with unfinished basements, the addition of a duct system may be relatively simple and inexpensive, but in other cases, this option is usually expensive and frequently impractical. In these cases, there are two other options for central systems:

• Mini-split units that distribute cooling by using two or three indoor sections connected to a single outdoor unit.
  
  
• Central air-conditioning systems that use small-diameter high-pressure ducts, designed to facilitate retrofit installation through walls, floors and attic spaces.

There are a number of things that you can do to reduce the need for mechanical cooling in your home, hereby minimizing the capacity and cost of the equipment that you purchase and the amount of electricity that it will consume. Actions you can take to reduce cooling requirements are as follows:

• Caulk and weatherstrip to seal air gaps, and ensure that the attic and exterior walls are insulated to meet or exceed the minimum recommended levels to minimize heat transfer to the interior.
  
  
• Use awnings, blinds or drapes to keep direct sunlight from entering the living space. Deciduous trees planted on the south and west sides of the house and wide roof overhangs will reduce solar heat gain to the interior in summer, while having only a small effect on heating in winter. Light-colored exterior finishes will also help reduce solar heat gain year-round.
  
  
• Turn on the kitchen rangehood fan when cooking, if it exhausts outside, and turn on the bathroom fan while bathing to minimize moisture buildup in the space.
  
  
• Turn off lights and appliances that are not needed. Plan heat-and moisture-generating activities (cooking, dish washing, drying clothes and bathing) for cooler morning and evening hours. Consider using appliances with time-delay controls. In addition to generating heat and humidity at a less noticeable time (after midnight, for example), your air conditioner will operate more efficiently in the cooler night hours.
  
  
• Select compact fluorescent lamps and energy-efficient appliances, since they produce less waste heat than conventional products. The electricity consumed by a less efficient refrigerator, for example, is converted to heat, which is released into your kitchen.

There are several common heat sources in a house.
Common heat sources in a house

Becoming informed about all aspects of air conditioning your home is the way to ensure that the correct choices are made for your particular cooling needs. This booklet identifies the commonly available air-conditioning equipment and discusses factors involved in selecting, installing, operating and maintaining an air-conditioning system. It provides you with a sound basis for making a smart purchasing decision.

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