Understanding your home's energy rating
This article is for educational purposes only and is not a substitute for professional advice. Local codes, regulations, and best practices vary by region.
Your home’s energy rating is a standardized score comparing your efficiency to similar homes. Different systems exist depending on your location: HERS scores in the US, Energy Star certifications, EPC ratings in the UK and EU. Understanding your rating helps you prioritize upgrades and track improvements.
HERS Score (US Standard)
The Home Energy Rating System is the industry standard. It uses a 0-100 scale where lower numbers mean more efficient. An average home scores 100. Homes above 100 are less efficient than average. Homes below 100 are more efficient. High performers score 50 to 70.
The score is calibrated against a standardized baseline home in your region. Reducing your score by 15 points typically saves 15 percent of energy. A certified HERS rater costs $300 to $500 to assess your home.
Energy Star Certification
Homes can earn Energy Star certification by meeting stringent efficiency standards set by region. Certification requires third-party inspection and testing. Energy Star homes are marketed as significantly more efficient. Buyers recognize it as a trusted indicator. Some utilities offer rebates for Energy Star homes or renovations. Achieving standards requires above-code construction or retrofits. Energy Star homes sometimes command 2 to 5 percent resale premium, though this varies by market.
EPC Ratings (UK and EU)
The Energy Performance Certificate uses an A-G scale where A is most efficient and G is least. In the UK and EU, EPC certification is required for all home sales. Ratings assess insulation, HVAC, renewables, water heating, lighting. The certificate includes upgrade recommendations. Poor-rated properties are harder to sell. Better-rated properties command higher value.
What Determines Your Rating
Construction year is the primary factor. Older homes are inherently less efficient. Climate zone matters; the same home is more efficient in mild climates than extreme climates. HVAC age, insulation quality, and window condition are major factors. Building envelope air tightness and insulation quality drive efficiency. Appliances and water heater efficiency determine baseline energy use.
Occupant behavior affects actual usage but doesn’t change the rating. The same home used differently by different occupants can show 20 to 30 percent variation in actual consumption.
Using Rating to Prioritize Improvements
An energy audit identifies upgrade priorities. Understanding your rating helps predict which improvements yield biggest gains. Combining improvement cost with energy savings potential informs decisions. Doing highest-impact improvements first maximizes rating improvement per dollar. After major improvements, reassess to quantify actual gains.
Limitations of Ratings
Ratings predict efficiency; they don’t determine actual consumption. Your utility bills show real energy use. Ratings can’t capture all factors affecting real consumption. Weather varies year-to-year. Occupancy changes affect usage. Rate increases complicate year-to-year comparison.
Improving your home might encourage increased comfort, offsetting efficiency gains. This “rebound effect” means actual savings might be less than predicted.
Combining Rating With Bills
Your utility bills measure actual energy use. Ratings predict. Both are useful. Track bills before and after improvements. Account for seasonal variation. In heating climates, winter bills are highest. In cooling climates, summer bills are. Weather normalization accounts for unusually hot or cold years. Occupancy changes require context when comparing bills.
Resale Value
Efficient homes sometimes sell faster and higher (regional variation). Some appraisers account for efficiency in valuation. Environmentally conscious buyers value efficiency. Some programs favor financing efficient homes. But don’t assume significant resale premiums. Affluent markets value efficiency more. Price-sensitive markets less. Market conditions matter more than efficiency rating.
Programs Available
Energy.gov and state energy office websites list available programs. Many states have efficiency standards or incentive programs. Local utilities offer efficiency ratings and rebates. Some cities require energy audits or efficiency standards for renovations. Rebates or tax credits sometimes tie to achieving ratings. Some programs offer low-interest loans for efficiency improvements.
The Practical Use
Energy ratings identify improvement opportunities and track progress. They inform decisions about which upgrades matter most. But ratings are predictions. Your actual energy use depends on behavior, weather, and occupancy. Use ratings as a guide. Verify improvements with utility bills. Set realistic expectations for resale value based on your market.
© The Whole Home Guide