When a Home Energy Rating System (HERS) rater steps onto a residential job site or into a home, they aren’t just there to perform a visual walkthrough with a clipboard. True energy compliance and performance tracking cannot be achieved by taking a quick glance at an AC unit or looking at duct runs in an attic.
At Grizzly HERS Testing, we operate on a simple principle: we measure, we don’t guess.
To catch the invisible air leaks, systemic pressure imbalances, and thermal losses that standard home inspections miss, our team relies on specialized, precision-grade technology. Demystifying these tools shows exactly how high-fidelity diagnostics lock in Title 24 compliance and guarantee long-term energy savings for San Diego builders and homeowners.
The Duct Blaster System: Measuring the Invisible
One of the most frequent tests required by California’s energy code is a duct leakage verification. Because the vast majority of a home’s ductwork is buried deep within walls, ceilings, or unconditioned attic spaces, visually finding leaks is nearly impossible. This is where the Duct Blaster system becomes essential.
To perform this test, our team seals off all the supply and return registers throughout the house with specialized temporary tape, making the ductwork a closed system. We then connect the Duct Blaster fan directly to the central return grille or the air handler unit.
The fan blows air into the system, pressurizing the ducts to a specific target level. A digital gauge tracks exactly how much air the fan must continuously push to maintain that pressure. If the system requires a high volume of air to stay pressurized, it means air is actively escaping through loose joints, tears, or poor seals. The equipment calculates the exact leakage percentage, giving builders a clear baseline to verify that their installation meets tight state thresholds.
The Blower Door: Evaluating the Building Envelope
While a duct blaster isolates the heating and cooling lines, a Blower Door system evaluates the airtightness of the entire structure—often referred to as the “building envelope.”
This diagnostic setup consists of a temporary, adjustable frame covered in airtight fabric that fits securely into an exterior doorway. Built into the bottom of this frame is a powerful, calibrated variable-speed fan.
When turned on, the fan pulls air out of the house, creating a slight negative pressure inside. To equalize that pressure, outside air rushes back in through any unsealed gaps, cracks, or penetrations in the home’s construction—such as around windows, electrical outlets, recessed lighting fixtures, or top plates.
By measuring the airflow required to maintain a depressurized home, the system delivers an incredibly precise readout of the home’s total air changes per hour. This data tells us exactly how well the building will retain conditioned air during hot San Diego summers and cooler winter nights.
The Brain of the Operation: The Digital Manometer
The fans themselves are only part of the equation. The real scientific work is done by the digital manometer—the highly sensitive electronic pressure gauge attached to these systems.
These devices don’t just measure pressure in standard units like PSI. Instead, they measure pressure differences in pascals, a microscopic metric of force. To put that in perspective, a single pascal is roughly equivalent to the weight of a single sheet of Post-it note paper resting on a table.
Because these instruments measure such incredibly minute pressure changes, equipment quality and routine calibration are paramount. Using cheap, generic, or uncalibrated tools leads to erratic data. For a builder, a faulty reading can mean a false failure that delays occupancy permits. For a homeowner, it could mean missing a significant efficiency defect that goes completely uncorrected.
How Precision Diagnostics Directly Benefits Your Project
Investing the time and utilizing top-tier diagnostic technology isn’t just about having fancy tools on the truck. It creates real, tangible benefits for everyone involved in the construction process:
For General Contractors & HVAC Installers: Precision data eliminates the friction of municipal inspections. When we hand you a certified HERS report backed by calibrated data, you have bulletproof proof that your work complies perfectly with the 2026 Energy Code.
For Homeowners: It eliminates the “performance gap.” You can buy the most expensive, high-efficiency heat pump or air conditioner available, but it will only perform as well as the building envelope and ductwork allow. These tests ensure you actually get the performance, indoor air quality, and utility savings you paid for.
High-Performance Tools for High-Performance Homes
Modern California homes are built to complex, high-performance standards and cannot be accurately evaluated using outdated methods. By using calibrated, field-tested systems such as Blower Doors and Duct Blasters, the team at Grizzly HERS Testing takes the guesswork completely out of the equation. Precision diagnostics ensure your project passes inspections smoothly, runs efficiently, and maintains low utility costs from day one.
If you have any questions about HERS Testing or would like to schedule a HERS Test, contact us today!
Grizzly HERS Testing
Grizzly HERS Testing is a certified HERS Rater and Energy Consultant. We specialize in Title 24 HERS Verifications, Residential HERS Testing, Mechanical Acceptance Testing and Title 24 Energy Calculations.