Category Archives: Ventilation

Keep the AC going on hot summer days.

Want to know if you air conditioning is working properly? Wait until it gets hot and then you will find out. If the AC can keep up to the load, then it is likely working properly.  If it cannot keep up or quits then you got issues. The hottest days of the year, is a bad time to call the for the AC guy, there could be 100’s calls ahead of you.

Air Conditioning systems, are sized to work on what is expected to be the hottest days of the year, which is about 97.5% of the time, for your area. This is the design temperature, that the engineer used to determined the size of the air conditioner. At this temperature, the amount of heat that is gained in a building, will be equal to the amount of  heat being absorbed by AC.  If more heat is gained, than can be absorbed, then the room temperature is going up.  The designer will allow for a little more capacity, and use a 10% safety margin and will select up,  the next available equipment size, above the design requirements.

If the compressor is running continuously without cycling off,  your AC is running at maximum capacity. This is normal on very hot and humid days. If the AC cannot keep up or if it is not the hottest days of the year, and your AC is running continuously just to keep up, then there is a problem.

There can be a lot of hidden issues with an AC system that will reduce efficiency but do not get noticed until weather gets hot. This loss of efficiency, affects your AC all year and it can cost you twice as much for electricity.  It can also damage the compressor and controls and will most likely to fail, when it is in highest demand, on the hottest days of the year.

Image of a AC system used in residential housing
Typical split AC system

AC Tip.

Two piece air conditioners have an indoor coil and outdoor coil and compressor. The two are connected with two copper pipes, a big pipe and a little pipe. The big pipe should be cool (~60°F to ~50°F) and the little pipe should be warm. (~80°F to ~90°F) If the big pipe is cold, ice forming on the pipe or the pipe is too warm then there could be a problem with the refrigerant charge.

If the little pipe is hot, then the condenser could be dirty or over charged with refrigerant. If it is too cool, where the line connects to the indoor coil, there could be a clogged filter, pinched line or  it could be under charged.

These problems can only be repaired by a qualified Refrigeration/AC Technician. Do not attempt to repair these systems yourself.