To analyze options for improving a building's energy performance, an energy auditor views its energy systems and its occupants as interrelated parts of an organic whole. Changes in one part can affect many of the others.
For example, a combination of air sealing, adding attic and wall insulation and adjusting equipment controls can often cure the problems of poor heat distribution and lower bills at the same time. Or if a new furnace or cooling system is really needed, a smaller, more efficient unit along with a tighter "thermal envelope" (the insulated shell of a building) and well-sealed ducts may be the best strategy.
The energy auditor uses a number of instruments to evaluate the function, efficiency and interactions of the energy systems in a building. Watt hour meters monitor refrigerator and freezer performance. Manometers, combustion analyzers and gas leak detectors help in assessing heating, cooling, ventilating and hot water systems for appropriate control settings, efficiency and safety. A calibrated, variable speed fan is temporarily mounted in a doorway and used to measure the relative tightness of the building and identify most sources of leaks. An infrared sensor helps to find insulation voids.
Did You Know?
Except when the wind is blowing particularly hard, the dominant force causing convective losses in homes is called "stack effect." The greater the temperature difference between the inside and outside - and the taller the dwelling - the greater the force of stack effect. The resulting discomfort and energy loss is at a maximum on the coldest day of the year, just when the furnace is working its hardest to maintain comfort. Since infiltration forces are greatest at the bottom of the envelope and exfiltration forces at the top, sealing openings in basements and attic floors is especially important.