Air conditioners

When it comes to keeping our homes cool, an air conditioner (AC) is likely the first option that comes to mind. Right now, about half of all Canadian homes have some form of stand-alone or cen­tral air conditioners. There are four popular types of AC for you to choose from: central, window, wall-through and portable.

Central ACs

If you have a detached or semi-detached house or a townhouse with ductwork, a central air (whole home) conditioner is the most cost-effective choice. There are single-stage units that operate con­tinually until turned off. These are the least expensive and the least efficient. Two-stage units operate at either full power like a single-stage unit, or at a lower capacity when the temperature is more moderate. Variable speed units operate at variable speeds depend­ing on the temperature in the home. They are the most expensive but the least costly to operate and the most efficient at maintaining consistent cooling levels.

Central ACs consist of an outdoor unit that houses a compressor, condenser coil, fan and some electrical components. An evaporator coil is usually installed on the furnace in the home, while a refrig­erant flows between the two via piping. The system draws warm air out of the house, cools the air and removes moisture, and then disperses the cooled air through the ductwork. The more com­mon refrigerant, halogenated chlorofluorocarbons (HCFCs), is being phased out and replaced by ozone-safe hydrofluorocarbons (HFCs). You really do need the services of a HVAC professional when selecting a central AC because there are a lot of factors to consider, apart for the square footage of the house.

Ductless mini-split ACs

If your home doesn’t have ductwork, a good alternative is a duct­less mini-split conditioner. These units consist of two components – an evaporator (a.k.a. “air handler”) is installed inside the home (on a wall or ceiling or freestanding on the floor) while a compres­sor/condenser is installed outside the home. Tubing between the two carries the refrigerant, power and water runoff. Similar to cen­tral ACs, mini-splits are classed by their BTU cooling output rating. The larger the square footage of a room the higher the BTU rating needed. Large homes typically require multiple air handlers, usu­ally connected to a single compressor.

Mini-splits are highly energy efficient, the air handler has a small footprint and they operate very quietly. They have the added advan­tage of being able to provide heat during cold seasons. Choosing the correct mini-split for your home is best done with the help of an HVAC professional.

Window ACs

When you need to cool a single room, a window AC can be a good choice. Most are designed to fit inside standard double-hung windows and include a slide-out chassis and mounting sleeve to stabilize and secure the unit. Window ACs with cooling capaci­ties of around 15,000 BTU or lower can be plugged into a standard 110V outlet. For larger capacity units you’ll need to install a 220V receptacle. Look for a CEER rating (combined energy efficiency rating) that’s at least 12.

Window ACs can also be very noisy (both inside and outside the house). Those with a higher BTU rating will be louder. The quietest window ACs are in the 44 to 52dB level (for comparison, nor­mal conversation has a decibel level of around 60dB, while most refrigerators run at about 50dB). Some models have built-in heat­ers, remote controls or are Wi-Fi enabled.

Wall-through (built-in) ACs

You’ll get better energy savings and better cooling perfor­mance from a wall-through (or in-wall) AC than a window AC. Essentially, it’s a window AC that’s permanently installed in your home’s exterior wall. Because a good portion of the unit is located outside the wall, they’re less obtrusive and quieter than window ACs. They come in a wide range of sizes, cooling capacities and prices. Features to look for include variable speed, built-in heaters, remote control and Wi-Fi connectivity. They do require the instal­lation of a wall sleeve and support to accommodate the weight of the unit. Homeowners with advanced DIY skills can install a wall-through AC, though it’s advisable to have an electrician do the electrical work.

Portable ACs

Portable ACs are free-standing units that require venting though a window. They’re typically more expensive than window ACs of the same cooling capacity. They’re also less efficient and noisier than window units and they take up more floor space. Read our review of the Frigidaire 3-in-1 air conditioner – it keeps rooms cool in summer, moistens dry air in winter, and cleans indoor air all year round.

Fans

Fans don’t cool the air, rather they circulate air to help it evap­orate perspiration from the skin. They work best when placed to maximize air flow. You can use fans in conjunction with an air conditioner running on a low setting to more efficiently circulate cold air around a room and from room to room. The most com­mon types are window, ceiling, floor / table and whole-house fans.

Optimally, window fans should be used in pairs. Position one fan on the shaded side of the house or on the windward side (the direction from which the wind typically blows toward the house) to pull air into the house, and, if feasible, locate a second fan on the opposite side of the room to push air out. In a multi-storey house have the fans pulling air in on the first floor and fans push­ing air out on the upper floors. When the outdoor temperature is higher than the indoor temperature window fans become ineffec­tive. During the hottest part of the summer they should be used later at night or early in the morning when the outside tempera­ture typically drops.

Size ceiling fans for the room in which they’re installed. An oversized fan will create an uncomfortable amount of airflow. In general, wider and longer blades will move more air. Remember to switch ceiling fans to rotate in a counterclockwise direction dur­ing the summer so that air is pushed downward. And because they cool by means of evaporation, it’s a waste of energy to keep them running when you leave a room. The new crop of smart ceiling fans can cycle on or off automatically based on room temperature, whether a room is occupied, or according to a personalized sched­ule. Some can also be connected to a home’s smart thermostat.

Floor and table fans offer the convenience of being easily moved around the house as needed. Variable speed allows you to adjust the fan’s output while a tilting head enables you to better direct air where it’s most needed.
Whole-house fans have been in use since the early 20th century. Mounted on top of a roof, they pull air in through open windows and exhaust it through the roof. During the hot summer months, they’re best used at night or early in the morning on days when the outside air temperature is lower than the temperature inside the house. Newer models have self-sealing insulated shutters that auto­matically close when the fan is turned off. Selecting the right size is best done in consultation with a HVAC professional.

Evaporative Coolers

The basic components of an evaporative cooler are a fan, an absorption pad and water. The pad absorbs water from a reservoir in the unit, and as warm air is pulled through the pad by the fan, water molecules on the pad evaporate, reducing the temperature of the air, which is then blown into the room. Some evaporative cool­ers have air filters to reduce allergens, oscillate to better distribute cool air, variable speed fans and remote controls. While they’re very energy efficient, they work best in areas where the outdoor rel­ative humidity is below 30%, making them a less attractive option for most Canadian cities.

Practical tips

• Whenever purchasing air-cooling products it’s advisable to select those that have the ENERGY STAR symbol. These products are certified as high efficiency.
• Bright sunlight brings a lot of heat into your home. There are sev­eral options to consider to reduce heat infiltration, including the use of window film (see “Window Film,” December/January 2020), insulated window shades and curtains, exterior shutters (see “Window Shutters,” October/November 2008) and awnings.
• Keep windows and window coverings closed during the day to reduce heat infiltration and block the sun’s heat.
• Hot air can seep into your home through gaps around windows and doors. Weather stripping and caulking doesn’t last indefi­nitely, and should be inspected annually and replaced as needed.
• Ensure that you have the right amount of insulation in your attic and that your attic is well ventilated. This will reduce the temperature in the attic and consequently put less of a strain on your air conditioner.
• Strategic landscaping can help reduce heat infiltration by shad­ing your house.
• Replace older windows and doors with energy-efficient units.
• If you replace your roof, use a light-coloured material to help reflect heat.