Saving Energy and Money
The total cost of heating and cooling the average U.S. home is about $2,000—and that price is rising. When you’ve got an energy-efficient air conditioning or heating system, you don’t have to be part of that statistic. That’s why it pays to calculate how much energy a new home comfort system can save you.
Understanding Energy Rating Systems
To help you make informed decisions about how to save energy, several rating systems have been developed.
The Seasonal Energy Efficiency Ratio (SEER) rating measures the efficiency of central air conditioners or heat pump usage over a theoretical cooling season.
It's a simple ratio of the amount of cooling provided by the air conditioner — as measured in BTUs — with the amount of energy the central system consumes — measured in watts/hr. So if you see a system rated at 16 SEER, that actually means it produces 16 BTUs per watt-hour.
But remember, a SEER number is theoretical. Your usage patterns — as well as proper equipment sizing and installation — will determine actual efficiency.
The Heating Seasonal Performance Factor (HSPF) measures a heat pump’s energy efficiency over one heating season combined with its SEER value over one cooling season. The HSPF formula is slightly more complicated. But the HSPF rating uses BTU to calculate useful heating output (including electric heat) divided by the total electricity energy heat pump consumed (in watt/hr) during the heating season.
The Annual Fuel Utilization Efficiency (AFUE) measures average efficiency for furnaces, boilers and water heaters. This is a measure for a theoretical heating season, not including electricity.
For SEER, HSPF and AFUE, higher numbers indicate higher energy efficiency. These numbers are then used in two energy rating programs: 
EnergyGuide label: Manufacturers of heating and cooling equipment are required to display the EnergyGuide label. This label estimates how much energy the equipment uses, compares energy use of similar products, and gives approximate annual operating costs. Your exact costs will depend on local utility rates and the type and source of your energy.
ENERGY STAR® certification: ENERGY STAR® is a voluntary energy awareness program developed by the U.S. Department of Energy and the Environmental Protection Agency (EPA). Our high-efficiency systems are labeled ENERGY STAR to identify products that are at least 15% more efficient than standard products.
Get the Right Size to Save the Most Money
In most homes, the heating and cooling system is too big. Besides wasting energy, improper size can create uneven temperatures, poor humidity control and maintenance problems over time.
Improper installation can reduce system efficiency by up to 30%. But properly sized ENERGY STAR® qualified equipment can easily cut your annual energy bill by hundreds of dollars. Programmable thermostats, like the York® Affinity™ Residential Communicating Control, can save you even more with improved energy savings, home comfort and peace of mind that your equipment is operating at peak efficiency.
- See more at: http://www.york.com/residential/getting-started/energy-efficient-savings.aspx#sthash.N6PS5ZjG.dpuf