Air Conditioner Efficiency

Air Conditioner Problem

Suppose an older home in San Antonio is equipped with a central air-conditioning unit with SEER rating equal to 6 and that this home consumes 36,000 kWh of electrical power each year to power this system. Suppose this system is replaced by a central unit with a SEER rating equal to 18.

1.  How much energy (in kWh) is consumed annually by the central A/C unit after the upgrade?

Energy Consumed =

= 36,000 kWh • Old SEER / New SEER= 36,000 kWh • 6 /18= 36,000 kWh • 1 /3= 12,000 kWh

2.  How much energy is saved annually by switching to the A/C unit with the higher SEER rating?

Energy Saved =

= 36,000 kWh – 12,000 kWh= 24,000 kWh

3.  How much money is saved annually, assuming that the cost of electricity equals $0.10/kWh?

Money Saved =

= 24,000 kWh • $0.10/kWh= $2,400

4.  What is the payback period if the cost of purchasing and installing the new A/C unit equals $4,800?

Cost = $4,800Savings= $2,400/yearPayback = Cost / Savings = 2 years