Using The

Air Conditioning Carbon Footprint Calculator

It seems that everywhere we turn, we hear environmentalists warning that global warming will doom

our planet unless we do something dramatic. Despite the rhetoric that the science has been

settled, there is still debate about man's role in the warming of the planet. Whether you take

the former or the latter position is irrelevant.

Replacing an old, inefficient air conditioner with a new, 13 SEER or higher model can yield

drastic reduction in a homeowner's "carbon footprint."

The carbon footprint calculator uses the following formulas…

The emissions factor is a constant, provideded by the U.S. EPA, based on the mix of power plant

fuels used for electricity. The emissions factor is based on North American electricity grid.

Even though the emissions factor might vary for a local market, the grid is interconnected and

electricity is fungible, which means a consumer's electricity reduction ultimately reduces

generation by the national average.

Demand (Watts) = Capacity (Btu) / SEER

Energy Consumption (kWh) = Demand (Watts) X Cooling Load Hours

Carbon Footprint (Lbs of Carbon) = Energy Consumption (kWh) X Emissions Factor

© 2007 Service Roundtable

Air Conditioning Carbon Footprint Calculator

Enter the capacity of the air conditioner

in Btuh: 36,000 Btuh 36,000 Btuh

You can enter nominal or actual.

Enter the nameplate SEER when new: 8 SEER 13 SEERThis is the theoretical SEER, based on the limited test

laboratory test points required for product certification.

Estimate the reduction in SEER due to

installation & performance degradation

over time: 2 SEER - SEER

Rarely will an air conditioner operate in the field at the

nameplate efficiency rating. Lab conditions are ideal. Field

conditions are not. Lab tests are based on a limited number of

repeatable test points. Field conditions run the gamut of

operating conditions. Lab installations are perfect by design.

Field installations typically fall very short of perfection. Lab

test feature new equipment. In the field equipment

performance degrades over time (and without maintenance

degrades faster and farther). Thus, average operating SEER

always falls short of lab conditions when new and becomes

worse with time. Estimate the SEER reduction.

Operating SEER: 6 SEER 13 SEER

This is the actual estimated operating SEER.

Demand: 6,000 Watts 2,769 WattsThis demand is the watts of electricity drawn by the air

conditioner when on.

Enter Cooling Load Hours: 1,800 Hours 1,800 HoursThe cooling load hours is the number of hours an air

conditioner will normally run over the course of a year for a

geographical area.

Annual Energy Consumption: 10,800 kWh 4,985 kWh

The annual energy consumption is the amount of electricity

consumed by the air conditioner over a year's time.

Emissions Factor: 1.37 1.37 The emissions factor is supplied by the EPA and represents a

blended average of the carbon content resulting in electricity

generation nationwide.

Air Conditioner Carbon Footprint: 14,796 Lbs of Carbon 6,829 Lbs of Carbon

Carbon Footprint Reduction: Lbs

© 2007 Service Roundtable

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