Portland Home Energy Score:
What It Measures and What You Can Do With It
Portland requires a Home Energy Score for most residential sales. Here’s how the score works, what it tells buyers, and what homeowners can do before they list.
Portland homeowners planning to sell need to think about the Home Energy Score before they list. The city requires it for most residential sales. Buyers see the score right in the listing. It sits there next to the bedroom count and the square footage, a number from 1 to 10, and buyers notice it.
What the score means, how it’s calculated, and what you can do about it before listing: that’s what this post covers.
One clarification before we get into it: a Home Energy Score assessment is not a home inspection. These are two different things done by different people. A home inspector evaluates the physical condition of the home: systems, structure, roof, electrical, plumbing. A HES assessor estimates energy use based on the home’s characteristics. If you’re preparing to sell, you likely need both.
What the Score Actually Measures
The Home Energy Score is a number from 1 to 10. A 10 is the most energy-efficient. A 1 is the least. The U.S. Department of Energy developed the scoring system. Portland adopted it for home sales.
The score models how much energy the home uses for three things: heating, cooling, and water heating. It does not account for plug loads, appliances, or how the current occupants actually use the home. It’s a model of the house itself, not the household.
To calculate the score, a certified assessor visits the home and records:
- Foundation type and insulation level
- Wall construction and insulation
- Attic insulation depth and type
- Window type and area (single-pane, double-pane, etc.)
- Heating and cooling system type, age, and efficiency
- Water heater type and efficiency
- Air sealing (estimated or blower-door tested)
That data goes into the DOE’s scoring tool, which outputs the score and produces a report. The report also includes a projected score if you made specific upgrades, so you can see what changes would move the needle.
Why Portland Adopted This Requirement
Portland has a goal of reducing carbon emissions from the built environment. Homes are a big part of that picture. Heating and cooling accounts for a large share of residential energy use, and Portland’s older housing stock isn’t especially efficient.
The city’s reasoning is straightforward: buyers can’t act on information they don’t have. By requiring disclosure at listing, Portland ensures buyers know what they’re buying from an energy standpoint. A home that costs $300 a month to heat is a different financial picture than one that costs $100 a month. That’s useful information before you sign.
It also creates an incentive for sellers to improve. If a low score might affect buyer interest, there’s a reason to invest in insulation or a more efficient furnace before listing. Some sellers do. Others list as-is and let the score speak for itself.
What the HES requirement covers in Portland
- Required for most single-family homes listed for sale in Portland city limits
- Applies regardless of the home’s age; exemptions include manufactured and floating homes and stacked condo units
- Must be performed by a certified HES assessor using the DOE protocol
- The score and report must be disclosed to buyers at the time of listing
- The requirement is enforced through the listing process: the score must be obtained before listing and included in the listing
Typical Scores in Portland
Portland’s housing stock skews old. A significant portion of homes in close-in neighborhoods (SE, NE, North, inner SW) were built before 1950. Many of those homes have:
- Little or no attic insulation, or insulation that’s been compressed or degraded over decades
- Uninsulated or poorly insulated walls
- Single-pane windows or early double-pane windows that have failed seals
- Older gas furnaces running at 60-70% efficiency
- Minimal air sealing throughout
The result is a lot of scores in the 2-4 range for older homes. A score of 5 represents a home with average energy use. Getting there or above it often requires at least one meaningful upgrade, usually insulation or heating system.
Newer homes or homes that have been updated with modern HVAC, good insulation, and quality windows score higher. A well-insulated home with a heat pump and no major air leaks can reach the 7-9 range.
The score alone doesn’t tell you whether the home is in good condition. A home can score a 3 but have a solid roof, good bones, and updated electrical. A home can score a 7 but have serious structural issues. The energy score and the physical condition of the home are separate questions.
What Affects Your Score the Most
Not all upgrades are equal. The biggest drivers of the score, roughly in order of impact:
Heating system efficiency has an outsized effect. An older gas furnace running at 60% efficiency compared to a modern unit at 95%+ efficiency is a large difference in modeled energy use. Heat pumps score even better in Portland’s climate because they move heat rather than generate it.
Attic insulation is often the single most cost-effective upgrade. Most older Portland homes have inadequate attic insulation, sometimes a few inches of compressed fiberglass from the 1960s. Getting to current recommendations (R-49 or higher) can meaningfully improve the score and the actual comfort of the home.
Air sealing matters but is harder to quantify without a blower door test. Drafty homes lose a lot of energy through gaps around penetrations, at the top and bottom plates, and around windows and doors.
Windows have less impact than most homeowners expect. They’re expensive to replace and the score improvement is often modest compared to insulation or HVAC upgrades. That said, failed double-pane windows (foggy glass, broken seals) contribute to heat loss, and replacing them is worth considering if they’re near end of life.
Water heater type matters too. A heat pump water heater scores significantly better than a standard electric resistance unit, and better than most gas units as well.
| Upgrade | Typical Cost | Score Impact |
|---|---|---|
| Attic insulation (to R-49) | $1,500 – $3,500 | High |
| Gas furnace replacement (95%+ AFUE) | $4,000 – $8,000 | High |
| Heat pump (air source, replacing gas) | $8,000 – $15,000 | Very High |
| Air sealing (professional) | $500 – $2,000 | Moderate |
| Heat pump water heater | $1,200 – $2,500 | Moderate |
| Window replacement (per window) | $400 – $1,200 | Low to Moderate |
Real Inspection Photos
Energy Findings From Real Inspections
Real photos from Russ's reports of the items that move a Home Energy Score most.
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Attic insulation below current depth standards. Adding insulation is often one of the most cost-effective upgrades. -
A thermal camera showing heat loss at an attic hatch that was not insulated or weather sealed.
How to Prepare Before the Assessment
The assessor will walk through the home and record what’s there. You don’t need to do anything special to prepare, but a few things help:
Make sure the assessor has access to the attic and crawlspace. These are critical for measuring insulation and evaluating the building envelope. An assessor who can’t get into the attic will have to estimate conditions, which isn’t ideal.
Have documentation ready if you’ve done upgrades. If you replaced the furnace or added insulation in the last few years, having records of the work, including the equipment model and efficiency rating, helps the assessor use accurate data.
Know that the assessor will ask about the vintage of major systems. How old is the water heater? When was the furnace last replaced? Approximate answers are fine, but accurate information produces a more accurate score.
The Home Inspection Connection
A Home Energy Score assessment and a home inspection are different things. But they complement each other.
A home inspection looks at the visible condition of the home’s major systems. That includes the HVAC system, attic insulation, windows, weatherstripping, and building envelope, all of which also affect the energy score. An inspector using thermal imaging can show temperature differences that may point to heat loss, which relates to what a HES assessment measures.
If you’re preparing to sell, getting a pre-listing home inspection before your HES assessment can help. The inspection may surface insulation gaps, HVAC issues, or window failures that you’d want to address anyway. Fixing those before the assessment could improve your score. Either way, you’ll have a clearer picture of what you’re selling.
Thermal imaging is included free on every Trusted Home Inspections inspection. That camera can show temperature differences that may point to where heat is escaping through inadequate insulation or air gaps, useful information whether you’re preparing for a HES assessment or just trying to understand your home.
The Home Energy Score tells buyers how efficient your home is. A pre-listing inspection tells you, and them, what condition it’s in. Together, these two assessments give sellers and buyers a clearer picture before a transaction.
For homeowners preparing to list in Portland, start with a pre-listing home inspection to know what you’re working with. Then get your Home Energy Score done by a certified assessor. If you have questions about what a home inspection covers or want to book, use the online scheduler or see the pricing page.
Portland Home Energy Score FAQ
