Window Unit vs. Mini Split Efficiency

Written by:  Jackie S.

Problem:  Not a problem.  I have a Whirlpool 15,600 btu. window unit through the wall.  It cools to 70 degrees at a reasonable cost.  My question is can I expect an 18,000 btu. mini ductless to perform equally to my Whirlpool or better?  The sizing is right, I just don’t want to get too large or too small of a mini split air conditioner.

Solution: A mini split air conditioner will be a much more economical system than a window through the wall air conditioner.  Older window units are at or below 10 SEER.  Ductless mini split systems start at 13 SEER and at the 18,000 btu. size reach up to 16 SEER.  A 13 SEER unit will save over 30% on your utility bill versus a 10 SEER unit.  Also, mini split systems are much more quiet than a window unit.

My Mini Split Air Conditioner Won’t Start

Written by Terry M:

Problem:  My mini split air conditioner worked great last year when I purchased it and had it installed.  This year I turned on the inside unit and it only blows room temperature air.

Solution:  This is a pretty standard complaint for Springtime consumers.  There are two different strategies to try to find the problem.

1.  Check Electrical Wiring:  Make sure the outdoor condenser is operating while the power is “ON” for the indoor evaporator.  If the outdoor condenser is not operating check the outdoor electrical disconnect.  If it is a fused box make sure the fuses are still operational and the circuit breaker in the electrical box is “ON”.

Check that power is reaching the condenser, either 110 volts or 220 volts depending on the size of your condenser.  There are stickers on the outside condenser that will tell you the proper voltage.

You can then check that the contactor is receiving power between the terminals C and Y.  This should read 24 volts.

If both of these check out properly then it is probably a refrigerant problem.  If the evaporator is calling for power and the unit is low on refrigerant, the low pressure control will prevent it from operating.

2.  Refrigerant:  In most cases a loose fitting or crack in the refrigerant line set will leak the refrigerant that will have an oily feel.  You should call a HVAC professional to check the system.  Most systems will need to have the line sets vacuumed to remove any contamination that may have entered a crack and re-charged to manufacture settings.  This takes a special set of gauges for either R22 or R410A.