The beauty of a central air conditioning system is that it can distribute cool air through the whole house as opposed to window units which are generally designed to cool a single room. Despite the larger initial cost, a central cooling system can still save you money by reducing your monthly utility bill. If new or modified ductowork is required, then your initial investment will rise. Central air conditioning units also vary in size and efficiency. A common, costly error is to install an oversized unit in the home.
The most expensive part of an air conditioner to replace is the compressor. Air conditioners typically feature a scroll or reciprocating compressor, depending on the unit size and efficiency. Check to see if the compressor has an additional warranty (e.g. 10 year compressor warranty), separate from the standard cooling system warranty
And if you are wondering whether you should turn off the air conditioner so you can open a window to enjoy a break in the warm weather, here is some advice: do not continually turn on and off your air conditioner to adjust to the changing warm weather patterns outside. If you want to open a window to get some fresh air, it is better to leave your air conditioner on rather than turning it off. If the inside of the house gets hot and you have to turn the air conditioner back on then your air conditioner has to work harder to cool down your house and everything in it.