The make and size of the unit will depend on the size of the space that is looking to be cooled, for spaces that are high in sunlight, it is recommended to add at least 10% over on the BTU’s needed for the space.

Some minor noises can often be repaired, particularly if the unit is fairly new, but when louder sounds start happening like screeching, rattling, scraping, or other unusual noises, it's probably time for air conditioner replacement.

It depends on the age of the system, if it’s within 4-5 years, most likely you will be able to replace the outside unit with one of the same. Longer than 5 years it will likely be difficult to find parts or not cost effective.

Single stage- Runs at 100% all the time. Lower initial cost, smaller chance of failure, low maintenance and repair cost, low to average efficiency.

Two Stage- Runs at 70% average most times but can go to 100%. They cost more than the single stage upfront and to maintain, however over long periods of time the cost is offset by lower energy bills.

Clean or replace the filters often, always keep an eye on your blower motor and that it is functioning properly, and make sure to keep vents and intakes free of obstructions in your home. For gas furnaces always make sure your exhaust flue is free and clear.