Quality Insulation Inspection (QII)

QII: Quality Insulation Inspection for Title 24 California Energy Compliance

A Quality Insulation Inspection (QII) is a mandatory verification performed by a certified ECC (Energy Code Compliance) rater which was formerly a certified HERS (Home Energy Rating System) rater to confirm that a building's insulation meets the standards set by the California Energy Commission under Title 24. Whether you are building a new home, constructing an ADU, or completing an addition or alteration, the QII is one of the most critical steps in the compliance process.

In Sacramento Valley and the surrounding region, QII delivers one of the largest measurable increases in building performance. By verifying that the building envelope — the walls, ceilings, floors, and roof — provides continuous, uniform insulation, QII helps ensure that your home is energy efficient, comfortable, and code-compliant from day one.

What Happens During a Quality Insulation Inspection?

During a QII, a ECC-certified technician (formerly HERS-certified technician) reviews the building's Title 24 energy report and then performs a detailed, room-by-room walkthrough of the structure. The inspector checks every insulated surface to verify that what was specified in the energy report has actually been installed.

For example, if the Title 24 report calls for R-19 insulation in exterior walls, the ECC rater (formerly HERS rater) will confirm that R-19 or better is in place. Since homes use many different types of insulating material — batt, blown-in, spray foam, and rigid board — each type is verified using the appropriate method:

• Batt and blanket insulation — measured by thickness and compared against the manufacturer's stated R-value
• Blown-in (loose-fill) insulation — verified by weight per square foot using manufacturer specifications
• Spray foam insulation — measured for thickness at multiple points to confirm uniform coverage
• Rigid board insulation — checked for correct thickness and proper installation without gaps

The rater also uses specialized tools to check for moisture content within the insulation and may perform air leakage tests to identify and quantify any gaps in the thermal envelope.

Throughout the inspection, the ECC rater (formerly HERS rater) documents every finding with photographs and detailed notes, creating a comprehensive record for compliance purposes.

What Does a ECC/HERS Rater Look for in a QII?

A ECC rater (formerly HERS rater) (also known as a ECC/HERS inspector) examines several critical aspects of the insulation installation:

• Correct R-values — Every section of wall, ceiling, floor, and roof must match or exceed the R-values specified in the Title 24 report.
• Continuous coverage — Insulation must be installed without gaps, voids, or compressions that reduce its effectiveness.
• Top plate sealing — The rater confirms that foam strips are installed on the top plates of wall framing so that when drywall is installed, no air leakage occurs at the ceiling-wall junction.
• Electrical and plumbing penetrations — Where wires, pipes, or boxes pass through insulated cavities, the insulation must be properly split and fitted around them rather than compressed behind them.
• Proper air barriers — Insulation must be in contact with an air barrier on all six sides of each cavity to prevent convective air movement.
• Fire-stopping and draft-stopping — The rater verifies that required fire-stopping materials are in place at floor/ceiling penetrations and other code-required locations.

If any area falls short — for example, R-13 installed where R-21 is required — a correction notice is issued.

Correction Notices

During a QII, if insulation installation does not meet the standards of the California Energy Commission, a correction notice will be issued. Common correction items include:

• Insufficient R-value for the specified area
• Gaps or voids in insulation coverage
• Compressed insulation around wiring or plumbing
• Missing or incomplete air barriers
• Absent top-plate foam seals

Many issues can be corrected while the ECC rater (formerly HERS rater) is still on site. More significant corrections may require a follow-up visit with photographs and documentation proving the deficiency has been resolved.

Learn more about QII Correction Notices, examples, and best practices →

Types of Insulation Verified During a QII

Different areas of a building require different insulation types and R-values. During a QII, the ECC rater (formerly HERS rater) evaluates all of the following:

Batt and Blanket Insulation

The most common type found in wall cavities and between floor joists. Batt insulation is pre-cut to fit standard framing widths (2×4 and 2×6 walls). The rater measures thickness and confirms the R-value matches the manufacturer's specifications. Proper fit is critical — batts that are compressed, bunched, or leave gaps significantly reduce thermal performance.

Blown-In (Loose-Fill) Insulation

Commonly used in attic spaces and sometimes in wall cavities. Blown-in insulation is verified by weight per square foot, using the manufacturer's coverage charts. The rater checks for consistent depth and density across the entire area, paying special attention to corners, edges, and areas around obstructions.

Spray Foam Insulation

Both open-cell and closed-cell spray foam are measured for thickness at multiple points. Spray foam provides both insulation and air sealing, which can be a significant advantage for energy performance. The rater verifies minimum thickness requirements and checks for areas where the foam may have been under-applied.

Rigid Board Insulation

Used on exterior walls, foundation walls, and sometimes in cathedral ceilings. The rater checks board thickness, proper sealing at joints, and confirms that the material is installed per manufacturer specifications and the Title 24 report.

QII for New Construction

For new residential construction in California, a QII is required to obtain a building permit sign-off. The ECC/HERS-certified technician verifies that all insulation meets the specifications outlined in the energy report and that materials conform to all applicable building codes, including:

• R-value compliance for walls, roof/ceiling, and floors
• Flame spread and smoke density ratings for all insulation materials
• Proper installation per manufacturer instructions
• Compliance with California Residential Appendix RA2 provisions

The QII inspection typically occurs after insulation is installed but before drywall goes up, giving the rater full visual access to every insulated cavity. This timing is critical — once drywall is in place, verifying insulation installation becomes significantly more difficult and expensive.

QII for ADUs, Additions & Alterations

Accessory Dwelling Units (ADUs), room additions, and building alterations in California are subject to the same Title 24 energy compliance requirements as new construction. This means a QII is required for:

• ADU construction — Whether it is a garage conversion, detached backyard unit, or attached addition, all insulation must be inspected and verified.
• Room additions — Any new habitable space added to an existing structure requires QII verification of all new insulated areas.
• Alterations and remodels — When a project involves opening up walls or ceilings and replacing insulation, the new insulation must meet current code requirements and pass QII.

Because ADUs and additions often involve connecting new construction to existing structures, the ECC rater (formerly HERS rater) pays special attention to transition points where the old and new building envelopes meet, ensuring continuous insulation and air sealing at these junctions.

Why QII Matters: Energy Savings and Comfort

A properly performed QII is not just a code requirement — it directly impacts the long-term performance of your home. Buildings that pass QII with properly installed insulation benefit from:

• Lower energy bills — Properly insulated homes use significantly less energy for heating and cooling. According to the California Energy Commission, insulation improvements verified through QII can reduce heating and cooling energy use by 20–30%.
• Improved comfort — Uniform insulation eliminates hot spots, cold drafts, and temperature inconsistencies between rooms.
• Reduced HVAC wear — When insulation performs as designed, heating and cooling systems don't have to work as hard, extending equipment life and reducing maintenance costs.
• Higher home value — Energy-efficient homes with documented compliance certifications are increasingly valued by buyers and appraisers.
• Environmental benefits — Lower energy consumption means a smaller carbon footprint for your home.

Skipping or rushing through insulation installation — and hoping it passes inspection — is one of the most common and costly mistakes in residential construction. A thorough QII catches problems before they are buried behind drywall, saving thousands of dollars in potential rework and energy waste.

QII Certification

When all insulation is installed and verified to be in compliance with Title 24, the ECC rater (formerly HERS rater) issues a Certificate of Installation. This certification confirms that the installation matches the specifications the building permit was issued for and typically includes:

• The installer's company name
• The insulation manufacturer's name
• The type and brand of insulation material
• The installed R-value for each area
• The ECC/HERS rater's certification and signature

The insulation contractor is also required to complete their portion of the Certificate of Installation form and provide data sheets for all insulation materials used. This documentation becomes part of the permanent compliance record for the building.

QII Process Timeline: What to Expect

Understanding the QII timeline helps you plan your construction schedule effectively:

1. Pre-inspection coordination — Before insulation is installed, contact your ECC rater (formerly HERS rater) to schedule the QII. Provide a copy of the Title 24 energy report so the rater can review specifications in advance.
2. Insulation installation — Your insulation contractor installs all specified materials per the energy report.
3. QII inspection — The ECC rater (formerly HERS rater) performs the on-site inspection, typically taking 1–3 hours depending on the size and complexity of the project.
4. Corrections (if needed) — If deficiencies are found, the insulation contractor makes corrections. Minor fixes can often be completed the same day; more significant issues may require a follow-up inspection.
5. Certification — Once all insulation passes inspection, the Certificate of Installation is issued and submitted to the building department.

Tip: Schedule your QII early in the construction process. The inspection must be completed before drywall installation begins, and scheduling delays can hold up your entire construction timeline.

Frequently Asked Questions About QII

What does QII stand for?

QII stands for Quality Insulation Inspection. It is a required inspection under California's Title 24 Energy Code performed by a certified ECC rater (formerly HERS rater) to verify that insulation has been correctly installed.

Is a QII required in California?

Yes. A QII is required for all new residential construction, ADUs, additions, and certain alterations in California. It is part of the Title 24 energy compliance process and must be completed before drywall installation.

How long does a QII take?

A typical QII takes between 1 and 3 hours, depending on the size and complexity of the building. Larger custom homes or multi-unit projects may take longer.

What happens if my home fails a QII?

If insulation does not meet the specifications in the Title 24 report, the ECC rater (formerly HERS rater) issues a correction notice. The insulation contractor must fix the deficiencies, and a follow-up inspection may be required to verify compliance.

Can the same company install insulation and perform the QII?

No. The QII must be performed by an independent, certified ECC rater (formerly HERS rater) who is not affiliated with the insulation contractor. This ensures an unbiased, objective inspection.

How much does a QII cost?

QII costs vary based on the size of the project and the number of inspections required. Contact Poppy Energy for a free estimate tailored to your specific project.

Do I need a QII for an ADU?

Yes. ADUs are subject to the same Title 24 energy compliance requirements as new construction, which includes a mandatory QII before drywall installation.

What is the difference between QII and a blower door test?

A QII verifies the correct installation of insulation materials before drywall goes up. A blower door test measures the overall air-tightness of the finished building. Both are separate ECC/HERS verification requirements under Title 24, and both may be required for your project.

How Can Poppy Energy Help?

At Poppy Energy, our ECC/HERS-certified technicians provide thorough, professional Quality Insulation Inspections for projects of all sizes throughout Sacramento Valley and the surrounding areas. Our services include:

• QII for new construction — Single-family homes, custom builds, and production housing
• QII for ADUs — Garage conversions, detached units, and attached additions
• QII for additions and alterations — Room additions, major remodels, and envelope upgrades
• Coordination with builders and contractors — We work directly with your insulation contractors, energy consultants, and designers to keep your project on schedule
• Duct leakage testing — Complementary ECC/HERS testing to verify air-tightness of duct systems
• Full ECC/HERS compliance packages — Bundled testing services for projects that require multiple ECC/HERS verifications

We understand that construction schedules are tight and delays are expensive. That's why we offer flexible scheduling, fast turnaround on inspection reports, and clear communication throughout the process.

Contact our team today to schedule your Quality Insulation Inspection or to get a free estimate for your project.