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The Difference Between an Energy Audit and Ratings

April 10, 2012

What’s an Energy Rating?

To many people, a home energy audit (also called an energy assessment) and an energy rating sound pretty much like the same thing but they’re not. An energy rating provides a comparative analysis on how energy efficient your home is when compared to other similar homes.

An energy rating will generate a HERS Index score for your home, based upon its energy performance. The Home Energy Rating System or HERS was developed by RESNET and is the nationally recognized system for calculating how energy efficient a home is. The lower the HERS Index score, the more energy efficient the home.

Why is an Energy Rating Important?

  • It helps you understand how energy efficient your home is when compared to others
  • Gives you a projected idea of the energy costs of your home
  • An energy rating is a recognized tool in the mortgage industry

What’s an Energy Audit?

The purpose of a home energy assessment, also known as a survey or energy audit, is to pinpoint where and how a home is losing energy, which systems are working inefficiently and what cost effective measures can be put in place to rectify the situation.

Certified RESNET Home Energy Professionals offer three different types of energy assessments, varying in scope and depth:

Home Energy Survey

A Home Energy Survey is a visual inspection that doesn’t include the use of diagnostic testing equipment. Its purpose is to assess the general energy performance of an existing home including:

  • Building envelope features (windows, doors, insulation, ducts) and ages
  • Heating, cooling and ventilation equipment types, characteristics and ages
  • Appliance and lighting characteristics
  • Comfort complaints
  • Visible moisture issues
  • Visible health and safety issues

A RESNET Home Energy Survey Professional (HESP) will request a review of utility use and billing history to better understand potential opportunities for savings. A report of the complete assessment is provided, including basic recommendations for improving the home’s energy efficiency, as well as low-cost, do-it-yourself tasks. Also included is information on relevant utility-based programs to encourage the homeowner to take action. A Home Energy Survey takes approximately one hour to complete.

Building Performance Assessment

A Building Performance Assessment includes everything in the Home Energy Survey, along with diagnostic testing using specialized equipment such as a blower door test, duct leakage tester, combustion analyzer and infrared camera to determine:

  • The amount and location of air leaks in the building envelope
  • The amount of leakage from HVAC distribution ducts
  • The effectiveness of insulation inside walls and ceilings
  • Any existing or potential combustion safety issues

A Building Performance Auditor (BPA) conducts a whole-house evaluation and performs computer software analysis to identify and prioritize proposed treatments for improvement. A detailed report will provide suitable retrofit recommendations and specifications, and direct the homeowner to suitable RESNET Qualified EnergySmart Contractors who can perform the work. A Building Performance Assessment takes 3-4 hours depending on the size of your home.

Comprehensive HERS Rating

A Comprehensive HERS Rating is the most in-depth performance assessment of an existing home. It consists of everything included in the Building Performance Assessment, and in addition, provides a computerized simulation analysis utilizing RESNET Accredited Rating Software to calculate a rating score on the HERS Index. The report will also contain a cost/benefit analysis for the recommended improvements and expected return on investment. Comprehensive HERS Ratings of existing homes will be required to qualify loan applicants for certain federally sponsored mortgage products.

Consult your local certified RESNET Home Energy Auditor or Rater about doing an energy rating or assessment on your home.

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