Although it would seem wise to buy an air conditioning unit that is overpowered for the space, the opposite is true.  An overpowered window (or central) air conditioning unit wastes electricity and doesn’t actually control the humidity within your home.

    Air conditioning units are rated by BTU’s.  It takes about 18 BTU’s an hour to cool 1 sq. foot of space.  If you have 1000 sq. feet of space to cool, the unit should have an output of 18,000 BTU’s.  Personnel in the store where you buy your air conditioning unit will figure the exact amount of cooling power necessary for your home.

     A central air conditioning unit costs about 20% less to operate than window units with the same cooling capacity; of course, the initial investment is somewhat greater.

     Be sure to keep filters checked.  Replace or clean dirty filters in window air conditioners.  Remove a panel on the front of the unit to reach the filters.  some filters may be washed in the kitchen sink, then lightly oiled (household oil); other filters have to be raplaced.  This information about type of filter is usually found in the owners manual.

      If you have window air conditioning units: Level the air conditioner.  If the unit is not level, the oil in the compressor is not flowing properly.  If the air conditioner sits on brackets, you may be able to adjust these to level the unit.  If the air conditioner sits on a concrete pad, you will have to leel the pad.  Do this by digging dirt from underneath the pad;  then pry it up with a pry bar, and force earth under the pad with a shovel.  Or, level the unit on a pad with wooden shims.  Do not start the unit for 2 full days.  Leveling permits the oil in the system to flow into the compressor component.  Clean the exposed surfaces.  Paint any sheet metal or exposed parts that have rusted.  Clean off the rust with a wire brush and steel wool.  Then spot prime the area with metal primer.  Coat the entire surface with a high quality metal paint to complete the job.


      If you have a central air conditioning unit:  Reset the dampers in your home, if there are separate ducts for air conditioning.  Replace filters.  Check the auxiliary drain pan under the unit, if the air conditioner has one, be sure the pan is clean and the drain works.  Start the air conditioner on a warm day & switch the thermostat from heating to cooling.  The unit should run smoothly. If not, carefully check hose connections.  The connections should fit tightly to the outside part of the air conditioning unit and to the furnace inside your home.  If the hoses are loose, use an auto hose clamp to tighten them.  If the connection cannot be tightened, or if the hoses are damaged, call a serviceman.

     There are several little tricks you can use during the summer months to help save air conditioning costs and energy; Apply the follwoing:  Remember that cool air drops.  When you are using a window unit, make sure that floor, side walls, and low-return registers and grill are closed.  Turn off window air conditioners in rooms that are not occupied.  If the room will periodically be occupied during the day, set the air conditioner at a temperature higher than the temperature setting in a room which is constantly occupied. Shade window air conditioner from the sun with awnings. If possible, place window air conditioners on the north side of the house. If temperatures are low at night in your area, use an attic fan or an exhaust fan instead of air conditioning.  Fans pull out hot daytime air and pull in fresh, cool nighttime air. Turn off the air conditioning while you’re on vacation. Keep the thermostat set at 78 degrees.  Leave the storm windows and doors on in the summer months.  Keep draperies closed-especially on windows that face the sun. Weather strip all air leaks.  Check for leaks in ductwork.  Leaks cause loss of cool air and heat.


central air uniit