Honeywell

A typical heat pump would lose almost 50% of its efficiency after 20 years, even if a typical "dust stop" filter had been installed. Also in 20 years, a unit's efficiency could degrade by 50% if it is not properly maintained. This would double the energy cost!

Pacific Gas & Electric Study

In the summer of 1990, Pacific Gas & Electric (PG&E) hired Proctor Engineering Group to investigate the potential energy savings in residential air conditioners and forced air gas furnaces. The study targeted clients with high utility bills.

The objectives of the study were to:

1. Identify the major problems with existing residential air conditioning installations.
2. Identify the major problems with existing furnace installations.
3. Determine what actions could be taken to correct those problems.
4. Estimate the potential savings from those actions.

The results are startling. Here is a summary of their findings on heating problems:

• 60% Fan Off Temperature above 90º F
• 60% Steady-state efficiency less than 75%
• 27% Gas leak
• 13% Low heat anticipator setting (caused short cycles)
• 7% incomplete combustion (Carbon Monoxide present)
• 7% Cracked heat exchanger

The PG&E study identified a significant source of untapped electrical and gas savings. In all cases the cooling energy use could be lowered by 10% to 30% without extreme effort. In addition, these repairs have the potential to improve customer satisfaction.

The Fresno project showed that the existing HVAC contractor infrastructure was not able to identify and solve the problems that led to the high bill complaints. This can be attributed to a business environment that concentrates on low first cost and lowest bid. This business atmosphere results in poor installations and inadequate time available to diagnose and repair extreme problems that exist.

North Carolina Alternative Energy Corp.

This non-profit organization examined air conditioning manufacturers' efficiencies versus the actual efficiencies that resulted after installation.

• 90% of the units tested exhibited some sort of energy-wasting problem.
• 50% had an improper refrigerant charge<./li>
• 40% failed to meet minimum airflow criterion. 20% were barely inside the range specified by manufacturers.
• A deficiency of only 20% in indoor airflow reduces the efficiency rating by 17%.

A 15% return air leak from a 120° attic could reduce efficiency by 50%!