New central AC question ?

Just saw your other post where you say you have a 2008 system, that means it is 13 SEER efficient, why are you changing? But...

Do the math, the answer is...... 1 SEER = $85 -$120 per year = appx. 10 years:

Assume a current 9 SEER (Seasonal Energy Efficiency Rating) system 10 years old, 10 SEER when new. Replace with a 13 SEER system (min. required Jan 2006), the increase in efficiency is:

13 new - 9 old = 4, 4/9 = 44% efficiency increase. Now assume a $300/mo utility bill. Energy.gov says 65% is due to cooling, x 65% = $195/mo. for A/C x 44% efficiency increase = $86../mo. for a 4 SEER increase = $21.50/mo. per SEER x 5 cooling months = $107.50 per year per SEER.

Note the savings diminish by going from high to higher because while 9 Seer to 13 Seer is 44% increase, 13 Seer to 14 Seer is : 14-13 =1 /13 = 7.7%. Also, Minimum SEER rating is scheduled to be 14 SEER, eff. Jan 2015. Energy Star is around 15 SEER ,depending on the system, but also on EER (efficiency at a constant 95 degrees).

If you live in the northern states, the payback would take longer than if you live in the south. There are other things to take into consideration besides energy consumption. Oftentimes, upgraded systems run quieter and carry a better warranty. On the other hand, high efficiency a/c units tend to be physically larger than the less efficient model. You may want to inquire about those things before making a decision.

Depends on how much it gets used. Say if you lived in the north where you may use it only a few months out of the year then no. Most contractors can tell you what your savings would be depending on the SEER rating per season and the climate in your area.