Buying or owning a home comes with a lot of obvious costs: mortgage, insurance, property taxes. But one of the biggest line items—energy use—is often misunderstood or overlooked altogether.
Whether you’re house hunting or living in your forever home, understanding how a home uses energy can help you:
Spot potential problems, including but not limited to energy waste
Compare homes more accurately
Reduce monthly bills
Improve comfort and efficiency
Here are six smart ways to uncover the full picture of a home’s energy usage—so you’re not caught off guard when the first utility bill arrives.
Most single-family attached and detached homes have an energy score or rating that estimates how much energy the home should use based on its features. This estimate is usually generated by an energy model and is referred to as an asset-based rating.
These models evaluate a home’s:
Insulation levels
Heating and cooling system efficiency
Windows and building orientation
And more…
The benefit? It removes occupant behavior from the equation, allowing for an objective, apples-to-apples comparison between homes. This can be especially helpful when evaluating homes during a purchase.
Offer a standardized comparison between homes
Can identify and predict the energy-savings impact of specific upgrades to help determine the return-on-investment (ROI)
Useful for long-term planning and resale value
Don’t reflect current occupant behavior. While this is a strength of asset-based models if you are buying a home, it’s a weakness if you want to identify patterns or if your family’s particular use of energy might be a cause of energy waste
Can’t detect maintenance issues (e.g., a clogged HVAC filter)
Are based on inputs that may or may not reflect the home’s actual physical characteristics. Especially in existing homes, it’s difficult to know the condition, quality, and specific characteristics of many of the home’s features such as insulation levels in the walls, window specifications, the home’s air tightness, HVAC systems, and appliances.
The Home Energy Ratings Index (HERS) provides an asset-based rating that includes a home’s annual estimated operating costs for energy. Most HERS are performed when a home is under construction. As a result, the HERS model has a robust set of accurate home features because items like wall insulation can be inspected prior to sheetrock installation. You can find HERS-rated homes on the RESNET Registry. There are approximately 4 million homes with a HERS index.
The U.S. Department of Energy’s (DOE) Home Energy Score (HES) provides an asset-based rating that includes a home’s annual estimated operating costs for energy. Most HEScores are generated for existing homes. Even when a certified Home Energy Score assessor does an in-field inspection of a home, many home features used in the model use inferred data (e.g., an assumed amount of wall insulation based on when the age of the home). The U.S. DOE has a DIY tool for homeowners to create an unofficial HEScore. There are approximately 250,000 homes with an official HEScore.
Pearl provides an asset-based rating that includes a home’s annual estimated operating costs for energy. Pearl includes these operating costs for newly constructed homes as well as existing homes. Pearl’s data about home features includes publicly available sources that are often used in the real estate market (e.g., to display a home’s characteristics on a listing page), but those publicly available sources often lack key information about a home’s performance features. As a result, Pearl enables homeowners and professionals to update the home’s record and increase the accuracy of the model over time. You can see a home’s Pearl SCORE and operating costs on the Pearl Registry. Pearl has scored 87 million single family homes.
Some homes waste less energy than others. Features like high-efficiency insulation, sealed ductwork, modern windows, and energy-efficient HVAC systems make a big difference—regardless of who lives there.
These physical characteristics significantly influence how much energy a home uses and how comfortable it feels day to day.
HVAC and water heater age and efficiency
Levels of insulation in the attic, walls, and floors
Air sealing around ducts, windows, and doors
Ventilation systems or mechanical fresh air
Window type and solar exposure
The ENERGY STAR Home Upgrade program provides information about the six high-impact, energy efficiency features that are designed to work together to deliver significant energy and cost savings.
Pearl provides guides and information about a variety of home features to help home buyers and homeowners to understand which features have the biggest impact on energy usage as well as non-energy benefits.
A home’s past utility bills offer real-world insight into what energy usage actually looks like from month to month. These are known as operational ratings, because they reflect how the home is being operated by the occupants.
Reveal true monthly costs
Reflect how systems, maintenance, and behavior interact
Can help detect abnormal usage or underlying performance issues with specific features (e.g., an HVAC system using a lot more energy than expected, or a well pump that runs 24/7 because of a water leak)
Highly influenced by occupant behavior (e.g., thermostat set points, number of people) and whether the occupant has a unique use that may not be applicable for a new occupant (e.g, owning an electric vehicle)
Require at least 12 months of bills to account for seasonal fluctuations, especially in climates where heating or cooling costs are significant
Vacations or having extra guests in a home can make certain months unreliable as a source for insights
Not ideal for comparing different homes without context
Ask for 12 months of utility data if you’re buying a home
Compare summer and winter usage patterns
Use ENERGY STAR’s Home Energy Yardstick to obtain a score and additional energy insights
To truly understand a home’s energy performance, it helps to look at:
What the home is designed to do (asset rating)
What it actually uses (energy bills)
What features are physically in place to support efficiency (equipment, insulation, etc.)
Each perspective offers part of the picture. Used together, these perspectives can reveal mismatches (like great equipment that’s underperforming) or opportunities (like easy upgrades with big payback).
Energy-efficient homes don’t just save money—they often provide better quality of life. That’s because many upgrades that improve efficiency also:
Improve safety and indoor air quality (better ventilation, reduced humidity, fewer indoor air pollutants)
Enhance comfort (more even temperatures, fewer drafts)
Enhanced resilience (protection from extreme heat and cold, even if the power goes out)
A poorly sealed or under-insulated home isn’t just more expensive—it can significantly compromise the quality of life of the occupants.
If you are in the buying process, be aware of the hidden costs of homeownership. When comparing homes, be sure to consider energy-related costs—but don’t let a high energy bill be a dealbreaker, especially if the home checks every other box.
While location, size, and layout will always carry more weight in real estate decisions, it’s helpful to understand how much each home might cost to operate. The good news? An “energy hog” can always be improved. You can upgrade equipment, seal air leaks, and boost insulation—but you can’t pick up a house and move it to a better neighborhood.
Understanding energy usage isn’t just for buyers. If you already own your home, you can:
Identify where you’re losing energy (and money)
Prioritize upgrades with the biggest impact
Improve your comfort and resale value
Energy use doesn’t need to be a mystery. With the right mix of data—what a home is designed to do, and how it’s actually performing—you can:
Make smarter buying decisions – whether you are buying a home, replacing a broken feature (e.g., air conditioner, furnace, water heater, etc.), or planning your next home improvement project
Avoid surprise bills
Improve comfort and efficiency year-round
