How Our Rating System Works
Modernize scores every window contractor and product on a one-to-five scale using a weighted formula:
Final Score = Σ (Criterion Score × Criterion Weight)
Each criterion is weighted based on how much it actually affects the outcome for you as a homeowner. For window contractors, installation quality and licensing carry the most weight because poor installation is the leading cause of air leaks, water intrusion, and energy loss — regardless of how good the window itself is. For products, thermal performance and durability drive the score.
Once the final score is calculated, it maps to a star rating:
- 4.75–5.00 stars: Excellent
- 4.25–4.74 stars: Very Good
- 3.50–4.24 stars: Good
- 2.75–3.49 stars: Fair
- 2.00–2.74 stars: Poor
- Below 2.00 stars: Very Poor
A five-star rating means a contractor or product is excellent relative to comparable options — not that it’s flawless. All ratings are evaluated within the same category. For a full explanation of the scoring formula and what each star tier represents, see our Rating Methodology overview.
Windows Contractor Rating Methodology
We evaluate window contractors by focusing on precise installation, energy performance, and long-term durability. While window quality matters, poor installation can cause air leaks, water issues, and reduced efficiency — which is why we place the most weight on workmanship, installation quality, credentials, and customer experience.
How we evaluate window contractors
Here’s how we break down each area we consider when scoring window contractors.
Workmanship and installation quality (22%)
Installation quality is the primary factor in window performance. We verify that contractors follow best practices for sealing, flashing, and fit, and deliver consistent results across projects. Contractors who install windows precisely, have few callbacks, and use effective sealing methods earn the highest scores.
Licensing and credentials (19%)
We verify that contractors hold the required licenses, insurance, and relevant certifications. Higher scores go to contractors with manufacturer certifications (such as Andersen or Pella), lead-safe certification where applicable, and clear, verifiable credential documentation.
Customer experience (18%)
Customer experience scores are based on reviews from multiple trusted platforms, considering overall satisfaction, consistency, and reliability. Higher scores indicate strong average ratings, consistent positive feedback, and minimal recurring complaints.
Pricing and transparency (15%)
We evaluate how clearly contractors communicate pricing, including written estimates, itemized quotes, and clear details about the scope of work. Contractors who are fully transparent about pricing and avoid unexpected costs earn the highest scores.
Responsiveness and availability (10%)
Responsiveness refers to how quickly and reliably a contractor communicates and schedules projects. We consider response times to inquiries, scheduling timelines, and communication clarity throughout the project. Contractors who respond promptly and keep clients informed earn higher scores.
Reputation and market presence (8%)
We look at how established a contractor is in your area, including how long they’ve been in business, their local presence, and overall visibility. Contractors with a strong community reputation and consistent market presence earn higher scores.
Warranty and post-service support (8%)
We evaluate both the strength of installation warranties and the contractor’s track record for post-installation service. Higher scores go to contractors offering longer installation warranties, clear service processes, and reliable follow-through on warranty claims.
Scoring philosophy
Our window contractor ratings are designed to reflect long-term results, not just initial impressions. Contractors who deliver precise installations, hold strong credentials, and keep customers satisfied earn the highest ratings. Providers with inconsistent workmanship, unclear pricing, or poor communication receive lower scores.
Windows Products and Brands Rating Methodology
Unlike contractor ratings, which focus on installation and service, our window product and brand ratings center on material quality, thermal performance, and long-term value. We prioritize how windows perform over time in different climates and conditions — not just how they’re marketed.
How we evaluate window products and brands
Here’s how we break down each area we consider when scoring window products and brands.
Performance and efficiency (22%)
We evaluate performance using key building science metrics, including U-factor (insulation performance), solar heat gain coefficient (SHGC), air leakage, and ENERGY STAR certification. Windows that provide strong insulation, controlled solar gain, and minimal air leakage earn higher scores, as these factors directly influence comfort and energy savings.
Durability and build quality (20%)
Durability reflects the materials, construction quality, and long-term reliability of the window. We assess frame materials (vinyl, aluminum, fiberglass, composite), seal integrity and hardware quality, and resistance to warping, moisture, and wear over time. Products with reinforced frames and high-quality components earn the highest scores.
Warranty coverage (16%)
We evaluate the strength and usability of manufacturer warranties, including coverage duration and terms, transferability, and the ease of filing claims and accessing customer support. Windows with lifetime or long-term, non-prorated warranties and strong claims support earn higher scores.
Value and pricing (14%)
We assess value by evaluating how well a product balances performance, durability, and cost. Windows with strong energy efficiency relative to price, a long lifespan with minimal maintenance, and a meaningful return on investment through energy savings earn higher scores.
Brand reputation (12%)
We evaluate brand strength based on market recognition and longevity, installer and contractor sentiment, and consistency of product quality across lines. Established brands with strong reputations and reliable product performance score higher.
Installation compatibility and ease (8%)
We assess product adaptability across various installation scenarios, including retrofit and new construction. Windows that are widely compatible, installer-friendly, and supported by clear installation standards earn higher scores.
Climate and regional suitability (8%)
Window performance can vary by climate. We assess how well products are suited for specific environmental conditions — such as hot climates requiring low SHGC, cold climates requiring low U-factor, and mixed climates requiring balanced performance. Products designed for strong performance in specific regions earn higher scores.
Scoring philosophy
Our window product ratings are designed to reflect real-world performance in your home, including energy efficiency, durability, and long-term value. Products that combine strong thermal performance, durable construction, and reliable warranties earn higher scores. Windows with weaker materials, limited efficiency, or poor long-term performance receive lower scores.