Upgrade those Air conditioning Units Now

Here are some notes on why it's a good idea to update your air units now as opposed to next year and beyond.
In a nutshell, it'll cost less money to buy the units now and more in the future due to mandates from the clean air act and the required efficiencies of the units which will change Jan. 1 2006.

AC units are rated with what is called a SEER (Seasonal Energy Efficiency Ratio). It is the similar to the efficiency rating on the furnace, the higher the number, the better the efficiency. Currently, the City of Columbus requires a minimum 10 SEER condenser be used (that may be as low as they go; I’m not sure off the top of my head).
As of January1stt, they are going to change the minimum requirement to be a 13 SEER condenser. One of our HVAC subs gave us a ballpark of a 30% increase in price. Additionally, the size of the condenser gets considerably bigger. This could end up being a problem if someone squeezed the condenser into a tight side yard or something like that. And if I remember correctly the other component of the AC system, the coil in the furnace gets bigger too. This could be a problem on replacement/ upgrade situations.
If the new coildoesn'tn’t fit in the existing plenum (the sheet metal box that sits on top of your furnace, where all the individual ducts run out of), you are then into replacing that as well.
It is considered that the 13 SEER iquieterer than a 10 SEER.
One thing that we're looking into is if the 30% increase in price is in direct relation to a 30% increase in efficiency and savings on the electric bill. If it was motivated by a true desire by the City to increase the energy efficiency and make things environmentally friendly, it is a good thing. It may just be the cynic in me, but I'm guessing Carrier and Lennox just have golobbyistssts. (Thanks architect-about-town, Richard Cissell for the info and commentary)
Currently this is true for the City of Columbus but the smaller municipalities often follow suit. In fact, I'm not sure that the federal government won't require them to anyway.
From the city:
January 1, 2006 the code changes for AC units. All new units will be required to be 13 seer in lieu of 10 seer currently. This, if not designed for, could pose a few problems:
a. Increase size of unit:
I i. A 5 ton 13 seer unit will be approximately.
i. . 7’-0” long and 3’-0” wide with two fans, a 2 ton 13 seer unit will be approximately. 3’x3’x3’ tall.
b. 13 seer AC units can’t be retrofitted to most existing furnaces.
c. Cost of 13 seer unit will increase approximately 30% over current 10 seer units