Energy Auditing and Green Awareness
Energy Auditing and Green Awareness covers finding savings and proving they are real: audit levels, benchmarking, energy metrics, weather normalization and financial screening, plus the environmental dimension of refrigerant and efficiency choices.
Audit types and metrics
- ASHRAE Level 1: walk-through, rough savings, low-cost list. Level 2: energy survey and analysis with end-use breakdown and a costed package of measures. Level 3: capital-intensive analysis with detailed modeling, possibly commissioning.
- EUI = annual site energy in kBtu ÷ conditioned floor area (kBtu/ft²·yr). Compare against similar buildings before trusting it.
- Weather normalization: use heating and cooling degree days and consumption per degree day, so a mild year is not mistaken for a successful retrofit.
- Screen measures with simple payback = installed cost ÷ annual savings; refine long-lived measures with life-cycle cost or savings-to-investment ratio.
Worked example
A 10,000 ft² building uses 1,200,000 kBtu/yr: EUI = 120 kBtu/ft²·yr. A controls package cuts consumption 15%, or 180,000 kBtu = 180 MMBtu. At $10/MMBtu the savings are $1,800/yr. Installed cost is $8,000, so simple payback = 8,000 ÷ 1,800 = 4.4 years - usually acceptable for controls, and stronger still if comfort or peak demand improves.
Green awareness
Efficiency ratings (SEER2, HSPF2, EER2) are tested at defined conditions and do not predict part-load performance in a leaky house. Refrigerant choice is now an audit item: documented leak rate and GWP determine a system's direct and indirect carbon footprint, and leak repair with proper recovery is often the cheapest green measure available.
Traps
Calling a walk-through a Level 2 audit; quoting savings without a weather-normalized baseline; and adding measure savings linearly when air sealing and thermostat setbacks interact.