How to improve AC cooling efficiency?

I've noticed that my AC takes longer than usual to cool the house, especially on hot days. The air filter is clean, but the cooling still seems weak. What could be causing this, and what should I check first?

Try adding a sprinkler hose outside to cool the unit.

How old is it?  Could the problem be with the thermostat?

Anne Miller wrote:Try adding a sprinkler hose outside to cool the unit.

How old is it?  Could the problem be with the thermostat?

Water sprayed on the condensing coils outside is helpful, if you do not have hard water.  If you get deposits built up on the coils they will not cool as well.

If the unit is in the sun build a shade over it to help it stay cooler, but leave enough room for plenty of airflow.

Check your ductwork to make sure the connections are still secure and there are no leaks.

I definitely agree with getting shade on the unit.  It’s cheap and effective.  I personally like a wooden fence-like structure (broad, thin pieces of wood stapled together—it allows airflow but blocks almost all direct light).

Also. Consider some living structure (vines) climbing up a fence.  Just leave room for access and carefully watch for stuff that will fall into the unit.  An occasional hose-down and wash-out is also good.  It keeps the unit free from stuff that blocks heat flow and drops efficiency.  Also, make whatever light-blocking barrier you create big enough to block light from many angles.



Eric

I'd like to add that making sure your coils are clean is a good step. Funk can buildup and cause the unit to work harder. A good cleaning can be useful, especially on older units.

You may have a refrigerant leak and/or the interior coils are icing up.  Can you get to the interior unit and remove a panel to check the coils?  They might be dirty as well.