| Air Conditioning - Staying cool while saving money
Residential air conditioning is a huge consumer of electricity in Ontario -- it takes the equivalent of full output of both the gigantic Nanticoke coal fired generating station and half the output of the Lambton generating station to meet the demand for power created just by residential air conditioning on a peak summer day. Nanticoke is Canada's No. 1 industrial air polluter, while the Lambton is No. 2 in Ontario.
Tips for purchasing an energy-efficient air conditioner
When you're shopping for air conditioners, look for SEER ratings of 13 or more for central air conditioning units or EER ratings of 11 or higher for room air conditioners. High-efficiency units generally cost more, but more efficient units can pay for themselves through reduced electricity bills. Newer units can use up to 50% less electricity than older air conditioners.
Central air conditioners are usually more efficient than room air conditioners. However, sizing your air conditioner to meet your home's needs is very important. Larger units, while generally more efficient, will not operate efficiently if they are over-sized -- they will cycle on and off frequently rather than running for longer more efficient periods. (See the Natural Resources Canada publication Air Conditioning Your Home for details about how to properly size a unit and other tips.)
When shopping for a new unit, always look for the ENERGY STAR label and then examine the SEER or EER rating on the unit's Energuide label (some Energy Star units are more efficient than others). Also look for a unit that has these features:
- Operates quietly
- A fan-only switch, so you can use the unit for nighttime ventilation to substantially reduce air-conditioning costs
- A filter check light to remind you to check the filter after a predetermined number of operating hours
- An automatic-delay fan switch to turn off the fan a few minutes after the compressor turns off
- A thermal expansion device (TXV), preferably factory-installed. The TXV improves high temperature performance, and helps the unit deliver its rated efficiency even under adverse conditions (such as inaccurate or low refrigerant levels). The device costs much less than the service call or inefficiency it guards against.
Tips for reducing the energy your unit consumes (and saving you money)
- Set your thermostat at 25°C or higher. Each half-degree setting below 26°C will increase your energy consumption by approximately 8%.
- Use bath and kitchen fans sparingly when the air conditioner is operating.
- Inspect and clean both the indoor and outdoor coils. The indoor coil in your air conditioner acts as a magnet for dust because it is constantly wetted during the cooling season. Dirt build-up on the indoor coil is the single most common cause of poor efficiency. The outdoor coil must also be checked periodically for dirt build-up and cleaned if necessary.
- Check the refrigerant charge. The circulating fluid in your air conditioner is a special refrigerant gas that is put in when the system is installed. If the system is overcharged or undercharged with refrigerant, it will not work properly. You may need a service contractor to check the fluid and adjust it appropriately.
- Reduce the cooling load by using cost-effective conservation measures, such as shading east and west windows. When possible, delay heat-generating activities, such as dish washing, until the evening on hot days.
- Over most of the cooling season, keep the house closed tight during the day. Don't let in unwanted heat and humidity. If practical, ventilate at night either naturally (e.g., by creating cross ventilation with open windows) or with fans.
- Try not to use a dehumidifier at the same time your air conditioner is operating. The dehumidifier will increase the cooling load and force the air conditioner to work harder.
You can use the Air Conditioning Comparison Calculator to see the average energy cost and emissions difference between high and low efficiency units. Or if you know know the size of the unit you want to purchase (in Btus), you can use these more specific calculators to estimate your energy costs and emissions:
| Air Conditioning Comparison Calculator |
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Select Air Conditioner type
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This calculator will give you an estimate of the energy and pollution costs for central air and window air conditioning units of different sizes. Your actual costs will depend on the amount you run your air conditioner, temperature settings and weather conditions, but this calculator will let you see the advantages of buying an energy efficient unit with a high Seasonal Energy Efficiency Rating (SEER) or EER over a less efficient unit. Look for the SEER or EER rating on the Energuide label on the unit or in the owner's manual. Click here for more information about Energuide and Energy Star.
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Annual operating cost
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Yearly smog and climate change emissions
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based on Toronto climate averages
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Nitrogen oxides (NOx)
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Sulphur dioxide (SO2)
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Equivalent CO2 emissions
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| Most effecient model available* |
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| Least effecient model available** |
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| Savings from purchasing most efficient model |
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CO2 reduction equivalent to taking
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*Central air: SEER=17, Window Unit EER=12 **Central air: SEER=10, Window Unit EER=8
Electricity price used is 9.7 cents per kilowatt hour, based on an average electricity rate of 5.5 cents per kWh. Other variable charges (distribution, debt retirement) are based on rates charged by Toronto Hydro. Customers must also pay a $12.43 fixed monthly charge, which is not included in these calculations. For more details, click here.
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SEER (Seasonal Energy Efficiency Rating): The efficiency of central air conditioners is measured by the air conditioning unit's seasonal cooling output in Btu divided by the seasonal energy input in watt-hours for an average climate. Many older central air conditioners have SEER ratings of only 6 or 7. To qualify for an ENERGY STAR label, units require a SEER of 13 or higher.
EER (Energy Efficiency Rating): The efficiency of room air conditioners is measured by the energy efficiency ratio (EER), which is the ratio of the cooling output (in Btu) divided by the power consumption (in watt-hours). The ENERGY STAR criteria for room air conditioners is 10.7 or 10.8 for units of less than 20,000 Btu/hr.
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