Energy Audits

OverviewBlower Door

Residential Energy Audits were made common place in the early 1980s with the Residential Conservation Service (RCS) Program that was a mandated part of the original National Energy Conservation Policy Act (NECPA) from the Carter Administration. Not all states implemented the RCS part of the NECPA, but many states did and performed millions of energy audits for free or a highly subsidized rate of next to free. The good news is that a new industry was created. The bad news is that it created an expectation that residential energy audits should be ‘Free’ or very cheap. Therefore, when the program subsidies ended, most of the market for residential energy audits evaporated with it. Now, with the return to even higher energy prices than in the early 1980s, audits are becoming a popular option again.

There are still utility sponsored programs in some states that offer free or subsidized audits. There are also many web-based Do-It-Yourself audits that are free. However, in most areas home owners desiring to have an energy audit done by a professional who comes to inspect and/or test their house, should expect to pay a significant fee for that service.

New house builders who build to ENERGY STAR standards must have the house independently tested and certified by a HERS Rater. HERS Raters operate under the only national standard for residential energy auditors. HERS stands for Home Energy Rating System and is a product of the RESNet, Inc.



RESNet is a national non-profit organization created in 1995 to standardize the process of rating residential dwellings for energy efficiency. The need for standards was driven primarily by the home mortgage industry in the 1980’s, but today is driven more by the energy efficiency industry. The RESNet organization created and maintains a set of ‘Standards’ that covers all aspects of the process. RESNet certifies Providers, Trainers, software and Raters. The Raters are known as HERS Raters. HERS (Home Energy Rating System) is the Index that is used to score all rated dwellings. ENERGY STAR requires a HERS Rater to certify a house, the Federal Government accepts a HERS rating for the Builder Federal Tax Credit, and several states require HERS Ratings on new houses to prove compliance with their Energy Codes. (The Federal Tax Credit does not specify exclusively HERS, but an energy usage index that is programmed into the RESNet software creates a standard compliance report.)

RESNet is the only nationally recognized standard for residential energy audits. For an auditor to become a certified HERS Rater, they must agree to work with a certified Provider, receive certified training, pass an initial test, own or have access to all the equipment required to perform the work, perform field work and submit reports under the supervision of a Quality Control Delegate (QCD) who works for a Certified Provider, and agree to perform work according to the RESNet Ethics Standards.

The Rating Process

A Rating can be done on any house, single or multi-family, up to 3 stories. An ENERGY STAR Rating can only be given to NEW construction.

Existing Houses

To complete a rating on an existing house, a home owner typically works directly with the Rater, like they would any other energy auditor or contractor. Typically they are new owners of the house or are ready to do major renovations and are looking for advice on how to make the house more energy efficient.

The Rater sets the appointment, performs on-site data gathering, performs on-site testing, and takes the information back to his office where the data is entered into the software to produce the report. The typical reports from the software contain a lot of numbers and graphics, but almost no narrative. It is up to the Rater to add narrative, photos, images, and/or make specific recommendations beyond the numbers, depending on what the customer has hired them to do.

New Construction

Ratings for new construction are done for builders who wish to qualify for the Federal $2,000 Tax Credit for new houses (planned to expire at the end of 2008 if not extended), or are going for ENERGY STAR Rating because of their marketing plan. To qualify for the Tax Credit, a house typically scores a better HERS Rating number than ENERGY STAR requires, but each system has their ‘pros-and-cons’ and ‘standards/specs’ so a builder may not necessarily want to do both at the same time for the same house. It is possible to get the Tax Credit – score a better Rating Index, yet NOT get an ENERGY STAR approval because some requirement that did not make a large impact on the numeric score was not met in the ENERGY STAR Standard.

Builders hire a Rater BEFORE construction begins or at least before the framing is enclosed. The Rater reviews the plans and specs and provides a Preliminary Rating. If the specs don’t make the score needed, the Rater will work with the builder on changes to improve the score. The Rater then must inspect the house as it is being built to assure that the specs are being followed. At the completion of the building, the Rater performs diagnostic testing to certify that the house meets the Standards. Blower Doors, Duct Blaster and Indoor Air Quality (venting, flue gas analysis) are the typical tests done by the Rater upon building completion.

The ENERGY STAR is determined by the HERS Index (number) given to the house by the Rater.   The ‘Star’ is actually ‘5 Star’ as the old ENERGY STAR system is still available and does award 1 – 5 stars. The HERS Index required for the number of stars is determined by Climate Region, with 100 considered the standard (reference) house built to the national energy code and ‘0’ meaning a zero-energy house (ie: VERY efficient and on-site renewable energy power production generates as much power as the house needs.)

ENERGY STAR is gradually becoming synonymous with ‘5 Stars’. However, it would not be technically wrong for a builder to market a house as ‘ENERGY STAR’ even if the house got only 3 stars.

A Rated house gets a certificate printed by the RESNet/HERS Provider from the software after it has passed the final site testing and quality control process.


Tools of the Trade

The tools required to become a Rater can be a barrier to some that may otherwise be doing just basic energy audits. Most energy auditors I’ve been meeting are already ‘tooling up’ because they’ve learned they need to have a more sophisticated approach to their work in order to have credibility with their potential customers. Customers paying several hundred dollars for a service expect more than a flashlight and NCR hand-written form report. However, I’ve heard from others who think they can get more work by keeping their prices down and using a low-tech approach. This may be more of a reflection on the energy auditor than their market. There is certainly a market for different approaches. But, to be a HERS Rater, the following tools are required and additional tools are recommended.

Required Tools

  • Computer with RESNet-approved software
  • Blower Door and manual gauges
  • Duct Blaster with manual gauges
  • Duct Hood to measure CFM Fan Flows
  • Flue gas analysis/detection equipment
  • Register Pan to check individual register pressures
  • Digital camera
  • IR Thermometer
  • Various hand tools such as ladders, flashlights, battery operated drill, screw drivers, tapes, etc

Highly Recommended Tools

  • IR Thermography camera
  • Bore scope
  • Computerized blower door controls and software
  • Multiple gauges for simultaneous testing of different areas

Basic tools can be in the $7,500 – $10,000 range, depending on what the auditor may already have. The biggest variable in the recommended tools is the IR camera, which range in price from $5,000 to over $20,000. There are rental programs for IR cameras, but everything else is typically purchased.


Software and QC Review

The approved software is listed on the RESNet site. Various licenses are available.

Rating Fee

Raters may charge whatever they want for their services. Raters charge anywhere from $250 to $1,700 depending on the level of service they provide and the location and size of the houses. Typical fees are $300 – $500.




More Information

IR Thermography

Blower Doors





Source: Text Bob Fegan 12/2008; photo Bob Fegan;


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