When researching the City of Portland home energy score program online, you might run across several different terms describing similar, but different things: Portland home energy audits, assessments, scores, and ratings. What’s the difference, and which one do you need to get?
Portland Home Energy Scores
This standardized scoring procedure was developed by the U.S. Department of Energy and adopted by Portland City Council on January 1st, 2017 to be the required method of scoring homes before they can be listed on the Portland real estate market. Performed by a licensed Home Energy Score Assessor, the Home Energy Score provides an objective estimate of a home’s energy use based on its “envelope” (foundation, roof, walls, insulation, windows), energy systems, and square footage. This energy score is communicated on a scale of 1-10, with 10 being the lowest energy use (good) and 1 being the highest (bad). The home energy score takes about an hour to produce, depending on the size of the home, and the cost for a score in the City of Portland is anywhere from $99-$300 (often depending on the size of the home).
Portland Home Energy Reports
That’s right, a Home Energy Report is just another term for the Home Energy Score, but the term “Report” may be preferred because it’s less confusing. Specifically, the Score refers to that number on the 1-10 scale, but the Report itself contains the Score and more! It is a standardized document produced by the Home Energy Assessor’s software that includes, in its entirety, the Score (1-10), an estimate of the home’s annual energy cost in dollars, the home’s estimated carbon footprint, along with recommended improvements to increase the score, lower the energy cost, and decrease the carbon footprint of the home.
Above and Beyond: Portland Home Energy Audit
An audit is much more involved than a Home Energy Score, typically taking 2-4 times as long to complete. Some Portland Home Energy Score providers are offering a full Home Energy Audit service to homeowners (we do not), but generally will charge extra.
There is no standardized procedure we are aware of, for performing a home energy audit, but it may include the following tests:
- A blower door test. This procedure is excellent for finding air leaks in the home’s envelope. First, a blower door is mounted in the frame of an exterior door on the home. With all other doors and windows closed as tightly as possible, it begins “sucking” all the air from the home. In the low-pressure environment, air flows into the home from all unsealed cracks and openings.
- Thermographic imaging. This test also attempts to find locations where heat is leaving the building envelope. A thermal imaging camera is used to find cool and hot spots, helping the auditor determine where insulation and air seals are working, and where they are not. They can also show abnormally hot electrical connections or components, and heat created by excessive friction.
Which home energy assessment you decide to use depends on your needs as a homeowner (or if you are required to get a home energy score prior to selling). If you have the time and extra money to spend on a full audit, it might help you decide whether new windows or better insulation are your best bet for improving home energy efficiency. If you’re simply looking to list your home on the Portland real estate market, then you may simply want the energy score. And while you’re at it, check out the Department of Energy’s Better Buildings Solution Center for detailed information on what the Home Energy Score means and how it is determined.