Most people associate ECC and HERS ratings with new construction or permit-required HVAC work. And they're right — that is where the majority of energy compliance inspections happen in California. But existing homeowners sometimes need a rating too, for reasons that have nothing to do with a building permit or a new heating system.
Utility rebate programs, PACE financing, energy-efficient mortgage products, and real estate transactions are four scenarios where an existing homeowner in the Sacramento area may find themselves needing an independent energy assessment of their home. This guide explains what an existing home ECC rating is, when you need one, what the process involves, and what you can expect from the results.
What Is an Existing Home ECC Rating?
An existing home ECC rating is an independent assessment of a home's current energy performance conducted by a licensed ECC (Energy Code Compliance, formerly HERS) rater. Unlike new construction ratings — which are tied to a building permit and produce a compliance certificate — an existing home rating focuses on documenting the home's energy characteristics as they actually are today.
The rating process involves a combination of visual inspection and field testing. The rater gathers information about the home's insulation levels, window specifications, HVAC equipment efficiency, duct system condition, and building envelope tightness. This data is entered into energy modeling software that calculates a HERS Index score — a single number that summarizes the home's overall energy performance relative to a standard reference home.
The output is typically an energy report and a HERS Index score. These documents can be used for a variety of purposes depending on why the rating was requested. Unlike a new construction permit inspection, an existing home rating does not result in a CF-2R compliance certificate filed with the state — the outcome is an energy report and score, not a compliance record.
Four Reasons You Might Need an Existing Home Rating
1. Utility Rebates
SMUD (Sacramento Municipal Utility District) and PG&E both offer rebate programs for homeowners who make qualifying energy efficiency improvements — upgrading insulation, replacing windows, installing high-efficiency HVAC systems, or adding solar. Some of these programs require a before-and-after HERS rating to verify the improvement actually occurred and to quantify how much energy savings the upgrade is expected to produce.
The pre-upgrade rating establishes a baseline. After the improvement is made, a post-upgrade rating documents the new performance level. The difference between the two — in HERS score and in projected energy savings — justifies the rebate amount. Without the ratings, the utility has no way to independently verify the improvement, so many rebate programs simply require them.
If you're planning a major energy efficiency upgrade and intend to apply for utility rebates, ask the rebate program coordinator whether ratings are required and at what points in the project they need to be completed. Scheduling the pre-upgrade rating before any work begins is critical — you cannot retroactively establish a baseline.
2. PACE Financing
Property Assessed Clean Energy (PACE) financing allows homeowners to finance energy efficiency and renewable energy improvements — solar panels, HVAC systems, insulation, windows, roofing — through an assessment on their property tax bill rather than a traditional loan. PACE programs are popular in California and widely available in the Sacramento region.
Many PACE lenders and program administrators require a HERS rating as part of the application process. The rating documents the home's current energy performance and helps verify that the proposed improvements are appropriate for the home and will deliver meaningful energy savings. Some programs use the rating to size the loan or determine which measures qualify for financing.
If you're exploring PACE financing for a home improvement project, check with your PACE program coordinator about their rating requirements before you start the project. Some programs require the rating before financing is approved; others accept it at different points in the process.
3. Energy-Efficient Mortgages
FHA and VA loan programs offer Energy-Efficient Mortgage (EEM) products that allow homebuyers to finance the cost of energy improvements into their mortgage. The idea is that a home's reduced utility costs can offset the additional loan payment, making it financially viable to borrow more upfront to make improvements that will pay back over time.
To access EEM financing, lenders typically require an independent energy audit or HERS rating that documents the home's current energy performance and identifies what improvements are cost-effective. The HERS rating establishes where the home stands today — and the energy audit component identifies what upgrades would deliver the most savings per dollar invested.
Real estate agents working with buyers who have VA or FHA loans should be aware of EEM as an option for homes that have obvious energy deficiencies — older HVAC systems, poor insulation, single-pane windows. A HERS rating is the starting point for accessing this financing tool.
4. Real Estate Transactions
A growing number of homebuyers want to understand a home's energy performance before they complete a purchase. Monthly utility bills are a significant ongoing cost, and a home with an inefficient HVAC system, poor insulation, or a leaky envelope can cost hundreds of dollars more per month to operate than a comparable efficient home.
The HERS Index score is the residential real estate industry's standard metric for energy performance. A home rated by a licensed ECC rater and assigned a HERS score gives buyers an objective, third-party assessment they can compare across properties. Some sellers order a HERS rating proactively to demonstrate their home's energy performance as a selling point. In high-end markets and among energy-conscious buyers, a favorable HERS score can be a meaningful differentiator.
Important distinction: A HERS rating for an existing home is not the same as a Title 24 permit inspection. You will not receive a CF-2R compliance certificate — instead you get an energy report and a HERS Index score. This is appropriate for rebate programs, financing, and real estate purposes, but it is not a substitute for a permit-required ECC inspection on HVAC replacement or new construction work.
What the HERS Index Score Means
The HERS Index is a scale developed by RESNET (Residential Energy Services Network) to measure home energy efficiency. The scale works as follows:
- 100: The reference point — a home built to 2006 IECC code standards. This is the baseline the index is calibrated against.
- 0: A net-zero energy home — it produces as much energy as it consumes over the course of a year.
- Below 100: More efficient than the reference home. Lower is better.
- Above 100: Less efficient than the reference home. Many older existing homes score 120, 140, or higher.
Homes built under California's current Title 24 code typically score in the 50–70 range, reflecting how much California's energy standards exceed the national reference point. Energy Star certified new homes in California generally score 55 or better.
For existing homes in Sacramento, typical scores vary widely depending on age and condition. A 1970s home with original windows, minimal attic insulation, and an aging single-stage air conditioner might score 130 or higher. A 1990s home with attic insulation upgrades and a newer HVAC system might score 90–110. A recently renovated home with modern equipment, added insulation, and sealed ducts could score in the 60–80 range.
The score tells you where you are. It also tells you — through the supporting energy report — where the biggest opportunities for improvement are and what impact different upgrades would have on your score and projected energy costs.
What Does the Rating Process Involve for Existing Homes?
An existing home rating typically takes two to three hours on site and covers the following:
- Visual inspection of insulation: The rater checks attic insulation depth and type, looks for wall insulation where accessible, and documents what exists versus what the energy model will need to assume.
- Window assessment: Window type, frame material, and glazing type are documented. Single-pane windows have a major impact on energy performance, especially in Sacramento's hot summers.
- HVAC equipment documentation: The rater records existing equipment make, model, age, and efficiency ratings. Older systems often have no efficiency documentation — the rater will use age-based defaults or measure performance where possible.
- Duct leakage test: The rater performs a duct pressurization test to measure how much conditioned air is leaking from the duct system. Leaky ducts in unconditioned attic spaces are one of the largest sources of energy waste in Sacramento homes.
- Blower door test: A blower door test measures building envelope airtightness — how much air leaks in and out of the home through gaps in the walls, ceiling, and floor. This data is entered into the energy model and affects the final HERS score.
- Data entry and modeling: All collected information is entered into HERS-certified energy modeling software, which calculates the HERS Index score and generates the energy report.
Before you schedule: If you're getting a PACE loan or a utility rebate, contact the program coordinator and ask exactly what documentation they require — before calling a rater. Some programs need specific forms, specific test protocols, or ratings completed at specific project milestones. Knowing this in advance lets your rater capture everything in a single visit rather than returning for a second trip.
How Long Does It Take and What Does It Cost?
On-site time for an existing home rating is typically two to three hours for a standard single-family home, depending on size and accessibility. Larger homes, homes with complex duct systems, or homes where the attic or crawl space is difficult to access may take longer.
After the site visit, the rater processes the field data, runs the energy model, and produces the written report. Most raters, including Roo's Ratings, can provide the completed report within one to two business days of the site visit.
Pricing for existing home ratings varies based on home size, scope of testing required, and the specific deliverables needed for your program or purpose. Call Roo's Ratings at (530) 300-4472 for current pricing and to discuss exactly what your program requires.
Sacramento Homeowners: Why Energy Performance Matters Here
Sacramento sits in California Climate Zone 12 — one of the most energy-demanding residential climates in the state. Summers routinely bring stretches of 100°F or above that last for weeks. Air conditioning is not optional — it runs continuously on hot summer days, and in homes with inefficient envelopes or leaky ducts, it runs even harder to maintain comfortable temperatures.
Most Sacramento homes are served by SMUD, which has some of the most robust utility rebate programs in California. SMUD actively incentivizes homeowners to improve energy performance and reduce peak demand. For homeowners considering significant improvements — insulation upgrades, duct sealing, HVAC replacement, window upgrades — a pre-upgrade HERS rating is often the first step toward accessing those rebates and making informed decisions about where to invest.
A HERS rating also gives you an objective baseline that documents your home's current condition. If you sell the home in the future, that documented performance history has value. If you make improvements over time, subsequent ratings track the progress. And if your energy bills seem inexplicably high, the rating and supporting diagnostic data often point directly to the cause.
Schedule an Existing Home Rating
Roo's Ratings performs existing home HERS ratings throughout the Sacramento region. We work with SMUD rebate programs, PACE lenders, and real estate professionals. Call to discuss your project and get a quote.
A Rating Gives You a Baseline and a Roadmap
Whether you're pursuing a rebate, applying for financing, buying or selling a home, or simply curious about how your home performs, an existing home HERS rating does two things that nothing else does: it gives you an objective, independently verified baseline of your home's current energy performance, and it gives you a prioritized roadmap of what improvements would have the most impact.
The energy report that accompanies the HERS score typically shows projected energy use by end use — heating, cooling, water heating, lighting, and plug loads — and models the impact of various improvement measures. That information helps you make smarter decisions about where to spend your home improvement budget and which upgrades will actually move the needle on your utility bills.
For Sacramento homeowners dealing with high summer cooling bills, uncomfortable rooms, or aging equipment that's clearly past its prime, a HERS rating is an excellent starting point. It replaces guesswork with data and gives you a clear picture of what's happening in your home and what to do about it.
Contact Roo's Ratings at (530) 300-4472 or send us a message to learn more about existing home ratings and to schedule an assessment for your Sacramento-area home.
