Title 24 Reports and Energy Calculations for Ontario
Title 24 Calcs prepares permit-ready Title 24 energy reports for Ontario. We cover new homes, ADUs, granny flats, room additions, remodels, and commercial projects. Most residential reports ship within 1 to 2 business days. Ontario is part of our full California cities service area.
Ontario California is a major Inland Empire hub. It centers on Ontario International Airport and the surrounding logistics and industrial zone. The airport's continued expansion has driven significant commercial and warehouse permit activity throughout the city. At the same time, Ontario's residential neighborhoods generate consistent residential Title 24 permit demand. The city spans project types from single-family homes and ADUs to massive distribution center facilities.
Ontario Title 24 — key facts:
• Provider: Title 24 Calcs prepares CF1R energy compliance reports for Ontario
• Climate zone: Zone 10 — hot inland San Bernardino County near Ontario International Airport
• Building department: City of Ontario Building and Safety Division
• Address: 303 East B Street, Ontario, CA 91764
• Phone: (909) 395-2010 | Portal: City of Ontario online permit portal
• 2025 code: In effect for all Ontario permits submitted on or after January 1, 2026
• Starting price: $250 for eligible residential projects
• Turnaround: 1 to 2 business days for most residential reports
Ontario Title 24 Climate Zone 10
Ontario California is in Climate Zone 10. The city's flat, inland valley location means summer temperatures regularly exceed 95 to 100 degrees. Zone 10 homes need higher insulation values than coastal Orange County projects. They also need more efficient HVAC systems and larger solar PV arrays. Commercial warehouses in Ontario's airport zone face strict energy compliance requirements. This includes lighting power density, HVAC controls, and mandatory solar PV.
Ontario's Building and Safety Division at 303 East B Street requires Title 24 energy documentation at permit submittal. Residential projects use the CF1R package. Commercial and industrial projects use NRCC-ENV, NRCC-MCH, and NRCC-LTI forms. Large warehouse projects may require detailed energy modeling. This helps meet the 2025 code's updated lighting power density requirements.
We confirm your exact climate zone by project address before starting any report. The California Energy Commission climate zone tool provides the official zone map. You can also view our full California Title 24 climate zones guide for zone-by-zone details.
We also serve nearby cities: Rancho Cucamonga • Fontana • Corona • San Bernardino • Pomona • Riverside. See our San Bernardino County page or the full cities index for all locations we cover.
CF1R Reports and HERS Testing in Ontario
City of Ontario Building and Safety Division requires a CF1R Certificate of Compliance for all residential permits that trigger Title 24. Title 24 Calcs prepares the CF1R using current CEC-approved software. The software uses the 2025 code. We register it with an approved HERS provider before delivery. As a result, it is ready for permit submittal.
| CF1RCertificate of Compliance — submitted with the Ontario permit application | CF2RCertificate of Installation — signed by the installing contractor in the field | CF3RCertificate of Verification — signed by a HERS Rater before Ontario final inspection |
HERS testing is mandatory for specific energy systems. A certified HERS Rater must verify duct leakage, heat pump refrigerant charge, ventilation flow rates, and battery readiness. This verification is required before issuing a certificate of occupancy. Your CF1R identifies all applicable HERS measures for your Ontario project.
Title 24 Services for Ontario Projects
New Home Construction in Ontario
New single-family homes in Ontario need a Title 24 new construction report for every permit submitted on or after January 1, 2026. Heat pumps are the prescriptive baseline for space and water heating. Solar PV and battery readiness provisions also apply to most new homes. We prepare the complete CF1R package. We register it and deliver it ready for permit submittal. See our residential new construction service page for full details.
Title 24 ADU, Granny Flat, and In-Law Unit Reports in Ontario
Ontario's established residential neighborhoods have seen ADU permit growth. Garage conversions and attached ADUs are common in Ontario's older residential areas where lot sizes are smaller than newer Inland Empire communities. A Title 24 ADU report is required for every new ADU, JADU, granny flat, or in-law unit submitted on or after January 1, 2026. The compliance path depends on how the project is classified. Title 24 Calcs confirms the correct classification before starting your report. See our ADU Title 24 service page for more information.
Room Additions and Alterations in Ontario
Room additions that add conditioned floor area trigger Title 24 compliance. All new walls must meet Zone 10 insulation values. Ceilings and windows must also meet Zone 10 fenestration requirements. Additionally, HVAC replacement, window replacement, and water heater replacement may trigger a report. See our room addition service page and alteration service page for details. If you are unsure whether your Ontario project needs a report, submit your project details and we will confirm before you pay.
Title 24 Compliance for Ontario Remodels
Common triggers for Title 24 alteration reports in Ontario include HVAC replacement and window replacement to meet Zone 10 U-factor minimums. Heat pump water heater installation and significant lighting changes also trigger reports. These scopes of work require energy compliance documentation at plan check submittal.
Commercial Title 24 Reports in Ontario
Ontario's commercial market centers on logistics facilities and distribution centers near Ontario International Airport. These large-footprint projects require NRCC-ENV and NRCC-LTI commercial forms with updated 2025 code lighting power density calculations. We prepare NRCC-ENV, NRCC-MCH, and NRCC-LTI forms for all nonresidential project types throughout Ontario. The 2025 code requires solar PV for most new nonresidential buildings. It also requires ASHRAE Guideline 36 controls for VAV systems.
Frequently Asked Questions — Title 24 Ontario
Which building department handles permits in Ontario?
City of Ontario Building and Safety Division at 303 East B Street, Ontario, CA 91764. Phone: (909) 395-2010. Permits submit through the City of Ontario online permit portal. Title 24 energy compliance documentation must accompany the permit application at the time of permit submittal.
What Title 24 climate zone is Ontario in?
Ontario is in Climate Zone 10. This is a hot inland San Bernardino County near Ontario International Airport climate. Zone 10 has specific insulation, window performance, HVAC efficiency, and solar PV requirements. We confirm your exact zone by project address before starting any report.
What is HERS testing and is it required in Ontario?
HERS testing is third-party field verification of energy systems. In Ontario, a certified HERS Rater must verify duct leakage, heat pump refrigerant charge, and ventilation flow rates. This is required before the building department issues your certificate of occupancy. Your CF1R identifies the applicable measures.
Do I need a Title 24 report for an ADU in Ontario?
Yes. All new ADUs, JADUs, granny flats, and in-law units submitted on or after January 1, 2026 require a Title 24 report in Ontario. Title 24 Calcs confirms the correct compliance path before starting your report.
How much does a Title 24 energy report cost in Ontario?
Pricing starts at $250 for eligible residential projects. All pricing includes HERS registration, plan-sized PDFs, and revision support. See our pricing page for current rates.
How long does it take to get a Title 24 energy report in Ontario?
Most residential reports for Ontario projects are delivered within 1 to 2 business days after we receive complete plans. Commercial reports typically take 2 to 3 business days. Rush options are available for urgent submittals.