4 ways to keep your house cool
According to “Canada’s Changing Climate Report” (changingclimate.ca), six of the 10 warmest years have occurred during the last 15 years, while the annual average temperature in Canada has increased at roughly twice the global mean rate. The report underlines that the effects of widespread warming are evident in many parts of Canada and are projected to intensify in the future.
In practical terms, it means our summers are getting hotter. Last year, B.C. towns had significantly more days above 30°C than ever before. And so did towns across Manitoba, Ontario and Quebec. Even in Atlantic Canada, there were more 30°C days than normal.
We’ve reviewed recent research into home cooling and talked to several HVAC (heating, ventilation and air conditioning) professionals to provide you with a range of options for keeping your castle cool.
Central Air Units
Adding a central air conditioning unit to your home is the most efficient way to cool a larger area. Two units may be needed in large homes or homes in hotter areas. They’re usually placed in areas that are less visible.
Great for homes without ductwork, a mini-split is efficient and can also provide heat in the cooler months.
Portable Air Conditioner
The upside of a portable air conditioner is that they’re easy to install, as they just need a window to vent out. The downside is they’re less efficient and louder than some other types of air conditioners. (Photo by Black & Decker)
Although a fan only cools the interior of a house if the exterior air around the house is cooler than the interior temperature, they always have the added benefit of offering a “wind chill” that makes it feel cooler inside. Placing two fans on either side of a room or house will offer strong cross-ventilation.
Although stationary, a ceiling fan can do a lot to move around the air in a room and make it feel cooler inside. (Photo by Big Ass Fans)
Cover the Windows
Closing blinds or curtains, especially during a sunny day, can go a long way to keeping the interior temperature of a house or room lower. And as long as you already have window coverings, it’s free.
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.
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.
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 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.
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.
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.