The proper size HVAC system depends on a number of factors. Bigger is not necessarily better. The bigger the unit, the more energy it consumes, if the unit is undersized then it will need to work much harder and will not produce enough air. It is very important that you have the correct size unit for your application
Troubleshooting your air conditioner system begins with a few common sense checks. It seems that air conditioning problems show up when the weather becomes very hot. If your air conditioning does not seem to be working, there are several things to rule out before you have to contact a professional. Checking these things first can save you a lot of aggravation and possibly money as well.
Refrigeration is an ever evolving technology with far reaching consequences and impacts. For example, when you install new HVAC systems they are hopefully going to last 15- 20 years. If the refrigerant that system uses becomes obsolete there is no way to add refrigerant and can affect repairs later on. One refrigerant cannot just be used in the place of another. An existing system would need to be retrofitted to accept a different refrigerant. The cost to retrofit can often be cost prohibitive.
There are many uses for refrigerants both commercially and residentially and the EPA classifies and regulates them by their usage and classification.