Now that spring is here, the summer months are coming quickly and its best to plan for your cooling needs now. To help with the process, here is an air conditioner buying guide to help you determine the right choice of your air conditioning needs.
Where do you start?
You should start with some very basic considerations. Is it a portable or temporary system, or a permanent built in appliance? Either way, the size of the room or home is the biggest factor in your choice. As well as the type of heating system you currently have. Of course, the cost is always a consideration as many units can cost thousands of dollars.
Besides these basics, you will want to consider the location of the unit. The amount of sun exposure. As well as the noise level and unit efficiency to mention a few. But before digging into the various options available. It's important for you to understand some common industry terms and rating specifications for air conditioners.
Energy Efficiency Ratings (EERs)
Room air conditioners are rated by the Energy Efficiency Ratings (EERs). These numbers measure the amount of energy a unit requires to deliver a given amount of cooling. A higher EER translates to lower relative energy use. Units with a high EER are usually more expensive initially, but may save you money by reducing your monthly energy costs. Weigh the price increase of more efficient models against the potential savings on your energy bill to find out if a high-efficiency unit is the right choice for you.
BTU’s (British Thermal Units)
The term, BTUs (British Thermal Units) measures the amount of heat an air conditioner can remove from the air over a given period. The higher the number, the greater the cooling capacity, but bigger is not always better. In order to properly cool a room you have to match the BTU capacity of the air conditioner to the dimensions of the room that needs cooling. An under powered air conditioner will not cool a large room properly. On the other hand, one that has too high of a BTU rating might cool the area to quickly. This doesn't give it time to dehumidify the air, which can leave the space feeling cold and clammy.
When selecting the appropriate BTU rating to match a room by square feet you should also consider the following. The ceiling height, sizes of windows and doorways. Also, will the unit be in a sunny room or a kitchen with extra heat from appliances.
SEER: Seasonal Energy Efficiency Ratio
When comparing central air conditioners, one term you will see repeatedly is the seasonal energy efficiency ratio (SEER). This a measure of how much energy the air conditioner uses to cool a home. Modern central air conditioners range from 13 to 28 SEER. The SEER is calculated by taking the total cooling output over the course of a summer, measured in British Thermal Units (BTUs), and dividing it by the total amount of energy the air conditioner uses over that same period.
These figures are based on a theoretical average climate for the whole country. In reality, the same air conditioner's performance may vary considerably based on how hot and humid it is outdoors.
Energy Star Ratings
Energy Star Ratings for central air conditioners are based on both SEER and EER. To qualify for the label, a standard split-system central air conditioner must have a SEER of at least 14.5 and an EER of at least 12. For single-package units, the requirements are lower: 14 SEER and 11 EER.
We mentioned earlier EER. This is another measure of air conditioner efficiency called the energy efficiency ratio (EER). This measures the air conditioner's efficiency at any given moment. It is simply the cooling capacity of the air conditioner, as measured in BTU per hour, divided by its energy consumption in watts.
The Energy Star label is only one award a central air conditioner can earn for efficiency. The Consortium for Energy Efficiency (CEE) goes beyond the Energy Star ratings by defining three additional tiers for super-efficient models. A CEE Tier 0 unit is one that meets the Energy Star criteria. Tier 1 split central air conditioners have a minimum of 15 SEER and 12.5 EER, Tier 2 air conditioners have a minimum of 16 SEER and 13 EER, while the Tier 3 specification is a minimum of 18 SEER and 13 EER.
Room Air Conditioners
Room air conditioners are very common and available for mounting in windows or through walls. In each case they work the same way, with the compressor located outside. Window or single room air conditioners are intended to cool just one room, so a number of them may be required for a whole house. Individual units cost less to buy than central systems.
Available in a number of sizes and cooling capacities, these types of units can be used as a primary cooling source in a room. Or if needed, in combination with your central AC. Before purchasing a window unit, you will want to take measurements to ensure it will properly fit your window. You'll also want to look at the outlet in your wall to make sure it's compatible with the kind of plug on the AC unit.
Window units are made for three different types of windows — standard, slider and casement. These units are installed in an open window with the hot air exhaust facing outside and the cool air return system facing inside. A shaded window will offer extra cooling efficiency.
Most units have a chassis or frame that supports the air conditioner. It is important to note whether the chassis is fixed or not. Units with a slide-out chassis can be installed in a window or a wall, while a fixed-chassis unit can only be installed in a window. A slide-out chassis enables easy maintenance and cleaning since the inside of the machine is easily accessible once you slide out the chassis.
Portable Air Conditioners
These types of air conditioners offer more flexibility on the installation side than window or in-wall air conditioners. Since they don't require permanent installation and can be moved from room to room. These units use the air from inside the room to cool the condenser and exhaust the hot air out of a hose that vents through a window, sliding door, wall or ceiling. Water is drained from portable air conditioners in different ways. In self-evaporating systems, often referred to as "swamp coolers," the water condensation is recycled back into the air. If you buy a unit with a condensate pump, excess water gets pumped outside through a hose. Other models require you to manually empty the water tank every few hours.
Split Systems – Central Air
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These systems are very commonly used throughout Canada and the United States. Inside the house, is the evaporator coil, which removes heat and moisture from the air. Outside the house, a metal case contains the condenser coil, which releases the heat, and the compressor, which pumps refrigerant between the two coils. The indoor component of the air conditioner is connected through a network of ducts. A blower circulates the cold air through them to reach all parts of the house. This type of system is the most economical to install in a house with a central forced air furnace, because it can share the duct-work used by the heating system.
Ductless mini-split systems
These units can be a good choice for houses that do not have ductwork. Like a basic split system, the ductless mini-split combines an outdoor compressor and condenser with one or more indoor air-handling units. These units are mounted high on the wall and have blowers attached. Tubing connects the indoor and outdoor units and circulates refrigerant between them. Each indoor unit is installed in a separate room and cools that room only, much like a window air conditioner.
The main advantage of ductless mini-split systems is that they can be installed without tearing up walls to install duct-work. This system allows you to control the flow of cold independently in each room or shut off altogether in empty rooms. If used to cool an entire house, mini-split systems are more expensive than ducted central air conditioning systems. Costing roughly 30 percent more for the same amount of cooling power. However, they are also more efficient, since they avoid the energy loss associated with duct-work.
Heat Pumps
Heat pumps are a variation of the traditional split system. During hot summer months, it pumps heat from the house and releases it outside. In the wintertime, it extracts heat from the outdoor air and uses it to warm the house. Air sourced heat pumps are effective for both heating and cooling in mild climates. Air sourced heat pumps do not generally work well when temperatures stay below freezing for a long time, so they are not the best choice for cold climates.
A specialized type of heat pump called a ground-source or geothermal heat pump, could be an option for colder environments. It works by drawing heat out of the ground rather than the air. However, while long term energy savings can be impressive, a geothermal heat pump costs much more than other types of HVAC systems and normally installed at the time of the homes construction.
Whatever type of air conditioning system you choose to invest in, look for energy efficiency appliances. A typical home in North America spends up to 17% of their income on heating and cooling costs so it will pay off in savings latter. You can also check with the various power providers and municipal, provincial and state governments for rebate programs associated with upgrading your homes heating and cooling efficiency.
If a new air conditioning system is not in your plans this year there are lots of ways to help cool you home, check our our previous article here. Ventilation for a Healthy Home and Life
