FAIRBANKS — What’s an energy rater, and an energy auditor, and why would I need one?
You hear the terms “energy raters” and “energy auditors” a lot when we talk about energy efficient buildings. Although they have similar titles, and are focused on energy use, the two positions are different. So what’s the difference, and which one do you need for your energy project?
Certified energy raters examine residential buildings — houses, apartments, etc. — and assess their energy use. Nowadays, this is done using software that models the energy use of a particular building — the amount of heating oil, electricity, natural gas or other fuels that the building will consume to keep occupants warm and comfortable during the year.
In Alaska, energy raters typically use AkWarm software, which is provided by the Alaska Housing Finance Corporation (you can see and download it at www.ahfc.us). To perform an energy rating, the rater first gathers data about a building. This entails walking through a building, measuring the size, counting the number of rooms and windows, examining the appliances and assessing the condition of building components.
Raters also will look at building plans and past fuel bills if available, and will perform a blower door test to measure the air leakage of the building. They also may perform additional tests, such as monitoring the electrical use of an appliance or using a thermal imaging camera to determine areas of high heat loss.
All of this data is then entered into the AkWarm software, which processes the building data along with average climate data for the building’s location and produces an energy rating. AkWarm produces an Alaska Home Energy Rating Score that rates buildings on a star system, with 1-star buildings being very energy inefficient and 6-star buildings being the most energy efficient buildings in Alaska.
You can download AkWarm software and use it to get a rough estimate of your home’s energy rating. However, for an accurate rating, it’s best to hire a professional energy rater certified by AHFC. Raters are trained in cold climate housing technology, building diagnostics and energy modeling, and have received national certification as building analysts from the Building Performance Institute. There are many reasons to hire an energy rater — for example, to qualify for an AHFC loan or to inform potential buyers about the energy use of the home. Energy ratings also are the beginning of the energy audit process.
Energy auditors typically work on larger nonresidential buildings, so they have received slightly different training than an energy rater. To become a Certified Energy Auditor, you must have a degree in architecture or engineering and three years of auditing experience (or significantly more experience without the degree). Auditors usually have expertise with the more complex mechanical systems found in non-residential buildings and more familiarity with the type of economic decision-making that occurs in larger organizations.
An energy audit typically begins with obtaining energy bills to benchmark the building’s energy use. The auditor will do a walk-through, then, depending on the level of the audit, may use energy modeling software to determine the most cost-effective, energy-saving measures.
Auditors use energy rating software to assess the effects of potential changes to the building; they run different scenarios and study the effect of the changes on the building’s energy use. This information is used, together with cost estimates, to prioritize which retrofits are best for a particular building. Many energy auditors work closely with the building manager to plan and stage the retrofits, taking into account those that reduce the most energy use for the least cost, but also that make sense for occupant comfort and the building’s use.
For instance, if the kitchen is used most often, the auditor might suggest retrofitting it before other rooms. Also, they will know strategies, such as performing envelope upgrades before purchasing a new boiler so the boiler is sized correctly for the reduced heating load. And finally, they will prioritize any health and safety concerns, such as addressing indoor air quality or structural repairs.
Although energy raters and energy auditors typically have slightly different training and work in different building sectors, many of the skills overlap and some people have extensive experience doing both. In Alaska, there are different certification requirements for those who work with residential structures and those who work with nonresidential structures; however, in the Lower 48, they are referred to as energy auditors.
Gradually, Alaskans have added the distinction between the two to reduce confusion and acknowledge the differences in certification requirements. When choosing a rater or an energy auditor, it is important to ask whether they have experience working with buildings such as yours, and it can be helpful to have them describe their process. Whether retrofitting your home or business, AHFC-certified energy raters and certified energy auditors both have the same goal: to help you save energy and save money.
Ask a Builder articles promote home awareness for the Cold Climate Housing Research Center. If you have a question, contact us at firstname.lastname@example.org or 457-3454.