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Cooling

Keeping our homes comfortable in the summer months is nearly as important as in the winter. 

Although Minnesota historically averages about 12 days a year of 90-degree or warmer weather, there have been increasing numbers of hot days and a significant number of days with high heat index numbers. As these extreme weather events continue, the health and safety issues for the elderly, the very young, and ill people make home cooling more important –and an increasing part of home energy costs. 

Air conditioning

You should try to have your air conditioning (AC) systems inspected annually. Proper maintenance of your AC system will improve its safety and performance, reduce energy use and electric costs, and prolong the life of your system. A typical central AC system inspection will cover a list of tasks such as checking voltage and belt condition, checking drain line, confirming proper airflow, and more.

Between annual checkups, there are several things homeowners can do to keep AC systems operating efficiently and safely. One key maintenance task is to routinely replace or clean AC filters. Clogged, dirty filters block normal airflow and reduce a system’s efficiency significantly. Central AC filters are usually located in the return duct near the furnace or air handler, while room air conditioners have a filter mounted in the grill that faces into the room. Filters should be cleaned or replaced per manufacturer’s recommendations; some may require more frequent attention if the air conditioner is in constant use, is subjected to dusty conditions, or you have fur-bearing pets in the house.

Other do-it-yourself AC maintenance tasks include keeping the area around the outside unit free of foliage or anything that can block airflow to the unit and keeping the coils of the outside unit clean and free of leaves, dust and other debris—spray with a hose. 

Central air conditioners have a life expectancy of about 15-20 years and can show signs of aging through refrigerant leaks, motor failures, and an inability to efficiently cool your home. Installing a new unit before the old one fails completely allows you time for careful shopping, as well as enjoying the energy savings of a high-efficiency unit. Proper sizing is critical when purchasing a new AC system. A properly sized unit needs an operating cycle long enough to balance the removal of both heat and humidity. Make sure that your contractor does a heat-gain calculation to ensure the proper sizing of the unit.

The seasonal energy efficiency rating (SEER) is another key consideration of AC systems. The higher the SEER rating, the more efficient it is for cooling. ENERGY STAR® qualified units must have a SEER rating of at least 14; SEER ratings go up to 20.


Keeping the heat out 

In summer, the sun is high and long in the sky. It may seem impossible to keep the heat out. But there are several things that you can do to minimize the sun’s effect on your house and stay cool indoors. 

  • Window awnings. Aluminum or canvas awnings installed over south-facing windows can reduce heat. 

  • Trees. Properly placed trees can provide cooling shade for the lawn and the house. Plant leafy trees on the west side of the house, at least 20 feet away to avoid future foundation or limb issues. 

  • Wide overhangs. When building a new home or remodeling, consider adding wide overhangs on the south side to shield the house and windows from the high summer sun. 

  • Insulation and air-sealing. The same strategies that keep our homes warm in the winter work to keep heat out in the summer. 

  • Windows and doors closed. Close windows and doors and latch them tightly when it is warmer outside than inside. 

Cutting down on heat indoors

Many of our daily activities produce heat or moisture in the home. A few changes can reduce temperature and humidity levels, adding to comfort and saving on air conditioning. 

  • Reschedule. Plan to use appliances like the oven, dryer, and dishwasher in the evening when it is cooler. 

  • Turn it off. Make sure that unnecessary devices or lighting are turned off or unplugged. 

  • Properly ventilate. When cooking or bathing, use exhaust fans to quickly remove heat and moisture. 

  • Let cooler air in. During cooler evenings, open the windows –but only if you are not using air conditioning! If you use A/C during the day, it is actually more energy-efficient to leave it running at lower levels overnight rather than opening windows and then restarting in the morning.

  • Use fans. Ceiling fans, box fans, and portable fans can be used to cool a room’s inhabitants (but not the room, so turn them off when you are gone!). Whole-house fans should be avoided in our climate. 

  • Install an air conditioning system. Central air conditioners can last 15-20 years when properly maintained. Energy-efficient window and wall units can cool individual rooms in rental units and older homes. 

  • Try a dehumidifier. High humidity in your home will make you feel even warmer, and it also encourages mold and mildew growth in the space. An energy-efficient dehumidifying unit can help a great deal. 

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