Cooling Advice

Although the Summer months are short and sweet in Wisconsin, air conditioning is needed to make it through. Whether your A/C unit needs a quick fix or it’s time to invest in a new central air conditioning system, Harker is here to help you keep your cool. Our HVAC technicians have been providing high-quality air conditioning services to Madison-area residents for more than 65 years. Don’t break a sweat when you start having problems with your A/C unit, call Harker.

Cooling Tips

  • Madison Gas & Electric and Alliant Energy recommend setting thermostats at 78 degrees for cooling. We find most people set their thermostats between 75 and 78 degrees.
  • Operating your air conditioning system during the day then turning the unit off at night and opening windows will cost you more to operate. When you open windows you allow moisture to dampen carpet, furniture, beds, drapes and other items. 40% of the operation cost of A/C is to remove moisture. If you run A/C during the day, keep windows closed at night.
  • A properly designed system will drop indoor temperature by one to three degrees per hour. An oversized system that cools down too fast will not properly remove moisture. Your home will feel clammy. Air conditioners operate more efficiently the longer they run continuously, and are sized so they don’t turn on and off frequently.
  • Do not use expensive pleated furnace air filters purchased from hardware stores, as they may restrict air flow. Use either the $1.00 standard air filter or purchase a high-efficiency spaceguard type filter from a HVAC contractor.
  • Furnace air filters are used for both heating and cooling. Check your filters monthly and replace them if necessary.
  • Do not place items which generate heat such as lamps, computers, TVs, or fish tanks under the thermostat. If direct sunlight from windows hits your thermostat you may have to relocate the thermostat.
  • We recommend constant fan operation to circulate, filter & mix the air. This will cost you virtually no money if you have a variable speed blower motor. Contact us for details.
  • Close drapes on the sunny side of the house.
  • Have your heating and cooling system checked by a qualified technician on a yearly basis. Plant a tree. One well-placed shade tree can reduce your cooling costs by 25 percent. For maximum benefit, place leafy shade trees to the south and west, and evergreens to the north.
  • During late afternoon and early evening, turn off unnecessary lights and wait to use heat-producing appliances. It’s also a good idea to shade south and west-facing windows during the hottest part of the day.
  • Maintain your central air conditioner by cleaning the outside compressor with a garden hose (be sure to shut off power at the fuse or breaker first). Keep plantings at least one foot away for adequate airflow.
  • Use ceiling and box fans to help circulate air throughout the house, and make sure your attic is properly ventilated. In the summer, use a ceiling fan to blow air down and create a wind-chill effect. In the winter, reverse the fan to circulate warmed air near the ceiling throughout the rest of the room.
  • Set the fan on your central air conditioner to “on” rather than “auto”. This will circulate air continuously, keeping the temperature more even throughout the house and aiding in dehumidification.
  • If you use a window conditioner, make sure it’s the proper size. It’s better to get one that is too small rather than too large. A larger unit will start up and turn off more frequently and won’t dehumidify the air as well.
  • Don’t judge the efficiency of your air conditioner by the sound of the fan shutting on and off. The blower will continue to circulate cooled air throughout your home up to 15 minutes after the compressor has stopped (The same holds true for the furnace).
  • Raise the thermostat to about 78 to 80 degrees when you go to bed or leave the house. A programmable thermostat will do this for you automatically.
  • If your home can’t accommodate central air conditioning, try a whole-house attic fan. This device pushes hot air out through attic vents, lowering the temperature throughout your home about 5 degrees in less than 10 minutes. Attic fans cost about 5 cents per hour to operate.
  • During the winter, remove window air conditioners and seal the windows with caulk and weather-stripping. You might also want to cover the central air compressor with a tarp to keep it clean.

Features and Benefits

Here are some features and benefits associated with today’s cooling equipment:


Variable Speed Outdoor Fan Motor


A Variable Speed Outdoor Fan Motor allows the system to run longer at lower speeds. This will help to lower electric bills as well as reduce noise.


Two-Stage Cooling


Allows the system to produce a moderate temperature air for most of the time while still allowing it to cool your home during extremely hot/humid days. This feature will also save you money on your electrical bills as well as increase comfort.

Raising Your AC’s Efficiency

What Is A SEER?

SEER stands for Seasonal Energy Efficiency Ratio – a measure of cooling efficiency for air conditioners and heat pumps. The higher the SEER, the more energy efficient the unit.


Combining an efficient AC with a variable speed furnace will raise the efficiency of the air conditioner even more. Getting your air conditioner cleaned and checked by Harker Heating & Cooling can raise the efficiency of your AC as well as prolong its running life.

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