Air Conditioning Size For Your Home

This is a great website for a comprehensive overview of buying the correct air conditioner and technology involved. http://www.popularmechanics.com/home_journal/home_improvement/1274616.html?page=1 This article from Popular Mechanics Home Journal explains the basics of how an air conditioner (split system in particular) works, what type of Freon one should use and how efficiency is rated. The article also goes into more detail explaining how size capacity is measured and price vs. energy savings. The sizing and reason for getting your home looked at by a certified contractor is below:

“Sizing For Capacity And Efficiency Your heating, ventilation and air-conditioning (HVAC) contractor will size your equipment to meet the specific needs of your home. Factored into the equation will be the age of your house, the number and quality of its windows, how well it's insulated, how many stories it has, its size, and, of course, local energy rates. Contractors use industry sizing models, such as Model J, but most use them as a reference, modifying the results to accommodate their own years of experience. A 1500-sq.-ft. ranch-style home, for example, might normally require a 2 1/2-ton air conditioner, but if it's not well insulated, or if a good many windows have western exposure, or if the trees offer little direct shade, then a 3-ton unit might be more appropriate. In any case, sizing is critical. If sized too small, the system will struggle, and even freeze over, on the warmest days. If sized too large, the system will cycle on and off too frequently, greatly reducing its ability to control humidity. It will also be less efficient. Keep in mind that efficiency ratings are measured at the factory, under conditions that may have little to do with your house. In any case, sizing is a job best left to seasoned professionals, and it's a good idea to seek out more than one opinion.”

Another important aspect to buying a new air conditioner is making sure the price and the benefits will balance out for you as an individual.

“The Price Vs. Efficiency Question Of course, you'll always pay more for high-efficiency appliances, so the critical question is whether you'll save enough in the long haul to come out ahead. And that, unfortunately, requires a region-by-region, even a house-by-house, assessment. You'll need to work closely with your contractor to make an informed decision. Don't assume that high efficiency always pays. It may from a good-citizenship perspective, but real dollars should drive the rest of the equation. And don't forget to add the cost of interest on the money gained or lost. All we can do here is provide some context. If, for example, your electricity costs you a low 6 cents per kilowatt-hour (kwh), and you live in a reasonably well-insulated home in the northern one-third of the nation, using your air conditioner 200 to 400 hours per year, a basic SEER 10 system is probably your best choice. There's little chance that you'd recover the several hundred extra dollars a SEER 11 or SEER 12 system would cost, spread over a 12- to 15-year projected service life. You may hope for longer service, and you'll probably get it, but don't count on it. A SEER 10 is also a reasonable choice if you plan to move in the next few years. On the other hand, if you live in Yuma, Ariz., and run your air conditioner 2000 hours per year, then it makes sense to buy the most efficient model you can afford. The same might be true if you live on the Eastern Seaboard and pay 11 or 12 cents per kwh, or if you live in a house with stone or brick exterior walls, where insulation is simply not feasible. In these cases, high efficiency really is a good investment. Prices vary by manufacturer and with local market pressures, but it's probably safe to say that each step up in efficiency will cost about $200. This may seem a paltry sum, and it is for many people, but when you consider that the equipment costs for an entire SEER 10 system might run $800 to $900, an increase of $200 to $800 is significant.”

The article also has a section of illustrated drawings describing maintenance. These should only be done per homeowners own risk. However, maintenance – especially yearly and right before the hot summer months – is necessary to keep one’s air conditioning system in the best running shape to prevent future problems.