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When it comes to selecting windows and doors for your home or commercial project, climate is the ultimate guide. The right fenestration products don’t just match your style—they’re engineered to perform in your specific regional climate, cutting energy costs, boosting indoor comfort, and meeting strict industry and government efficiency standards.
At PUERTANA, we design and manufacture windows and doors that meet or exceed ENERGY STAR® requirements for every U.S. and Canadian climate zone. Backed by third-party NFRC certification and rigorous independent testing, our products deliver precise energy performance data you can trust—all clearly labeled and accessible in our Energy Performance Database.
This guide breaks down North America’s key climate zone energy standards, including ENERGY STAR® 2023 criteria for the U.S., California’s strict Title 24 requirements, and Canada’s Energy Rating (ER) and U-factor rules. Whether you’re a homeowner, builder, or dealer, you’ll find the clear, data-driven insights you need to choose the perfect energy-efficient windows and doors for your location.
ENERGY STAR® & NFRC: The Foundation of Energy Performance
ENERGY STAR®—a joint program of the U.S. EPA and Department of Energy (DOE)—is the gold standard for identifying energy-efficient home and building products. For windows and doors, ENERGY STAR® eligibility is 100% based on NFRC ratings—the only third-party, scientifically validated performance metrics for fenestration products.
The National Fenestration Rating Council (NFRC) tests and certifies the total performance of our windows and doors (glass + frame), measuring core metrics that define energy efficiency:
- U-factor: Measures heat transfer through the product (lower = less heat loss/gain, better for extreme temperatures).
- SHGC (Solar Heat Gain Coefficient): Measures how much solar heat passes through the product (lower = less unwanted solar gain for warm climates; higher = more beneficial solar gain for cold climates).
- ER (Energy Rating): Canada’s all-in-one metric for thermal performance, combining U-factor, SHGC, and air tightness (higher = better performance).
Every PUERTANA product features an official NFRC label, with clear, accurate ratings for easy compliance and comparison. We never cut corners on testing—our products are independently simulated, inspected, and listed in the NFRC certification program to ensure data you can rely on.
U.S. Climate Zones & ENERGY STAR® Criteria (2023)
The U.S. ENERGY STAR® program divides the nation into four distinct climate zones—Northern, North-Central, South-Central, and Southern—with tailored performance criteria for windows and doors that took full effect in 2023. Our products meet or exceed all these requirements, with flexible options for the Northern zone’s prescriptive and alternative compliance paths.
ENERGY STAR® Qualification Criteria for U.S. Windows
| CLIMATE ZONES – U.S. | U-FACTOR | SHGC |
|---|---|---|
| Northern (Prescriptive) | ≤ 0.22 | ≥ 0.17 |
| Northern (Alternative) | = 0.23 | ≥ 0.35 |
| Northern (Alternative) | = 0.24 | ≥ 0.35 |
| Northern (Alternative) | = 0.25 | ≥ 0.40 |
| Northern (Alternative) | = 0.26 | ≥ 0.40 |
| North-Central | ≤ 0.25 | ≤ 0.40 |
| South-Central | ≤ 0.28 | ≤ 0.23 |
| Southern | ≤ 0.32 | ≤ 0.23 |
Northern zone windows qualify for ENERGY STAR® via either prescriptive (strictest) or alternative performance criteria—our full product line supports both paths.
ENERGY STAR® Qualification Criteria for U.S. Doors
Door performance standards are tailored to glazing area (the amount of glass in the door), with region-specific SHGC requirements for larger glazed areas:
| GLAZING | U-FACTOR | SHGC |
|---|---|---|
| Opaque | ≤ 0.17 | No rating |
| ≤ 1/2-Lite | ≤ 0.23 | ≤ 0.23 |
| > 1/2-Lite | ≤ 0.26 | Northern/North-Central ≤ 0.40 |
| > 1/2-Lite | ≤ 0.28 | Southern/South-Central ≤ 0.23 |
California Title 24: Exceeding Strict Regional Standards
California’s Title 24 Building Energy Efficiency Standards are the most rigorous in the U.S.—and for good reason. Designed to drive decarbonization and reduce energy use in the state’s unique climate, these standards demand next-level performance from windows and doors.
At PUERTANA, we offer a dedicated line of windows and doors with custom glass options engineered to meet and exceed Title 24 requirements. Whether you’re building or renovating in Northern California’s cool coastal zones or Southern California’s hot inland areas, our products align with the latest Title 24 updates (including the 2025 Energy Code’s focus on heat pump compatibility and decarbonization). Our team and authorized dealers are ready to walk you through the exact products that fit your California project’s compliance needs.
Canada’s ENERGY STAR® Requirements: ER Rating & U-Factor
Canada’s ENERGY STAR® program (administered by Natural Resources Canada) takes a holistic approach to fenestration efficiency, with two compliance paths for windows, sliding doors, and swinging doors: meeting a minimum Energy Rating (ER) or a maximum U-factor (with metric and imperial equivalencies for easy reference).
Our Canadian-compliant products exceed both paths, delivering industry-leading thermal performance for Canada’s cold climates and variable regional conditions.
ENERGY STAR® Qualification Criteria for Canadian Windows & Doors
| MINIMUM ENERGY RATING (ER) | or | MAXIMUM U-FACTOR |
|---|---|---|
| 34 | or | ≤ 0.21 |
Canadian U-Factor Equivalency (Imperial → Metric)
| IMPERIAL | METRIC (W/m²∙K) |
|---|---|
| 0.35 | 2.00 |
| 0.32 | 1.80 |
| 0.28 | 1.60 |
| 0.25 | 1.40 |
| 0.21 | 1.20 |
ER ratings combine solar heat gain, U-factor, and average air tightness—our products boast ER ratings well above the 34 minimum for unbeatable winter performance.
Our Commitment to Precision & Performance
Energy efficiency isn’t a feature for us—it’s a fundamental design principle. Every PUERTANA window and door is engineered with:
- NFRC-certified performance: Independent testing ensures our ratings are accurate, fair, and compliant with all ENERGY STAR® and regional standards.
- Climate-specific engineering: Custom glass packages, frame materials, and insulation for every U.S. and Canadian climate zone—from the frigid Northern U.S. and Canada to the hot, sunny Southern U.S.
- Transparent data: Our Energy Performance Search page lets you look up exact ratings for every product, by climate zone. Every window and door also features a clear NFRC label, so you have performance data at a glance.
- Regional expertise: Our team and authorized dealers know the ins and outs of local energy codes—from California’s Title 24 to Canada’s ER requirements—and are here to help you find the perfect product for compliance and comfort.
Find Your Perfect Energy-Efficient Solution
Your climate zone defines your energy efficiency needs—and we have the perfect windows and doors to match. Whether you’re looking to cut heating costs in the Northern U.S. and Canada, reduce cooling loads in the South, or meet California’s Title 24 standards, our NFRC-certified, ENERGY STAR® compliant products deliver performance, style, and durability.
Explore our [Energy Performance Database] to find product ratings for your climate zone, or contact our team for personalized guidance. Our authorized dealers are also ready to answer your questions and help you select the right windows and doors for your project.
At PUERTANA, we believe energy efficiency should never mean compromising on style or quality. For every climate, every project, every home—we build windows and doors that work with your environment.
