What is NPS?
NPS, Net Promoter Score, is a customer loyalty metric introduced by Fred Reichheld at Bain & Company in 2003. NPS is measured by asking a single question: "How likely are you to recommend this product or service to a friend or colleague, on a scale of 0 to 10?" Respondents are then categorised: scores of 9 or 10 are Promoters, 7 or 8 are Passives, 0 to 6 are Detractors. NPS equals the percentage of Promoters minus the percentage of Detractors. The range is -100 to +100.
The premise is that customers willing to recommend a product are loyal advocates who drive referral growth, while detractors actively damage growth through negative word-of-mouth. NPS captures both in a single number.
For Indian solar EPCs, NPS is particularly valuable because residential and commercial solar markets rely heavily on referrals. A high NPS predicts strong referral momentum; a low NPS predicts stalled growth.
Why NPS matters
For solar EPCs, NPS is the leading indicator of referral-driven growth. Promoters generate new customers at lower CAC than any paid channel; detractors slow growth through negative reviews and word-of-mouth. Quality EPCs measure NPS and act on it.
For investors and operators, NPS signals product-market fit and customer relationship health. Best-in-class SaaS companies (Apple, Tesla, Costco) achieve NPS above 70. Solar EPCs that achieve NPS above 60 typically have strong word-of-mouth growth.
For day-to-day operations, NPS surveys (especially transactional NPS at key moments) surface issues quickly. The follow-up "Why did you rate that?" question is often more valuable than the numeric score.
How NPS is measured and acted on
- Survey timing. Transactional (post-event) or relationship (periodic).
- Question delivery. Email, WhatsApp, in-app.
- Score collection. 0 to 10 scale.
- Follow-up question. Why did you rate that?
- Categorisation. Promoter, Passive, Detractor.
- Score calculation. % Promoter minus % Detractor.
- Trend tracking. Over time and cohorts.
- Closed-loop follow-up. Contact each respondent.
- Root-cause analysis. Detractor concerns.
- Improvement actions. Address systemic issues.
Benefits of NPS discipline
- Referral pipeline. Promoters identified.
- Churn prevention. Detractors addressed early.
- Operational signal. Trends spot issues.
- Customer voice. Direct feedback channel.
- Team alignment. Shared metric.
- Investor signal. Customer health proxy.
- Marketing content. Promoter testimonials.
Limitations and challenges
Simplicity vs nuance. Single number hides complexity.
Cultural bias. Indians often rate conservatively.
Sample bias. Survey responders not representative.
Score gaming. If tied to bonuses, manipulation risk.
Lagging indicator. Reflects past, not future.
Lack of action. Measuring without closing loop wastes effort.
NPS benchmarks for Indian solar context
| Segment | Typical NPS range |
|---|---|
| Residential solar EPC (quality) | 40 to 65 |
| Residential solar EPC (average) | 15 to 35 |
| Commercial / industrial solar EPC | 30 to 55 |
| Solar CRM SaaS | 30 to 55 |
| Solar marketplace | -10 to 25 (lower expected) |
| Solar O&M services | 20 to 50 |
Quick facts
| Question | How likely to recommend, 0 to 10 |
|---|---|
| Categories | Promoter 9-10, Passive 7-8, Detractor 0-6 |
| Formula | % Promoter minus % Detractor |
| Range | -100 to +100 |
| SaaS benchmark | 30 good, 50 excellent, 70 world-class |
| Origin | Fred Reichheld, Bain & Co (2003) |
| Related | CSAT, churn, retention, referrals |
Common mistakes about NPS
- Measuring without closed loop. Wasted effort.
- Skipping the why question. Loses the diagnostic value.
- Tying to bonuses without controls. Manipulation.
- Small samples treated as significant. Statistical noise.
- Ignoring Passive segment. Conversion opportunity.
- Comparing across very different industries. Apples and oranges.
- NPS without usage data. Partial picture.
- One-off measurement. Trends matter.
Key takeaways
- NPS measures customer loyalty: % Promoters minus % Detractors.
- Range -100 to +100; SaaS benchmarks 30 good, 50 excellent.
- Indian solar EPC benchmark above 40 competitive.
- Transactional and relationship NPS both valuable.
- Closed-loop follow-up is the action that drives value.
- Predicts referral velocity and churn risk.
- Combine with usage data and direct retention metrics.
Frequently Asked Questions
What is NPS?
NPS (Net Promoter Score) is a customer loyalty metric measured by asking a single question: 'How likely are you to recommend this product or service to a friend or colleague, on a scale of 0 to 10?' Respondents are categorised: Promoters (9-10), Passives (7-8), Detractors (0-6). NPS = % Promoters minus % Detractors. Range is -100 to +100.
Who created NPS?
NPS was introduced by Fred Reichheld at Bain & Company in 2003 through a Harvard Business Review article titled 'The One Number You Need to Grow.' Reichheld argued that the recommendation question correlates with future business growth better than traditional satisfaction surveys.
What is a good NPS score?
Industry-specific. SaaS benchmarks: above 30 is good, above 50 excellent, above 70 world-class. For Indian solar EPCs, benchmark NPS varies: above 40 is competitive, above 60 indicates strong referral momentum. Negative NPS is a red flag requiring immediate action.
How often should NPS be measured?
Two common approaches. Transactional NPS: after key moments (onboarding complete, project commissioned, AMC renewed). Relationship NPS: quarterly or biannual survey of full customer base. Quality SaaS measures both.
Does NPS predict retention?
Promoters churn less and refer more. Detractors are more likely to churn and warn others away. NPS thus correlates with retention and referral velocity. However NPS alone is imperfect; combine with usage data and direct retention metrics.
How can solar EPCs use NPS?
Survey post-commissioning and post-AMC to gauge customer satisfaction. Use Promoters for referrals and testimonials. Address Detractor concerns immediately to prevent churn and negative word-of-mouth. Track NPS trends to spot systemic issues.
What is the right NPS sample size?
Statistically significant samples typically need 50+ responses per cohort. Small EPCs can still use NPS for qualitative direction even at smaller samples. The follow-up question 'Why did you rate that?' is often more valuable than the number.
What is the difference between NPS and CSAT?
NPS measures loyalty and likelihood to recommend. CSAT (Customer Satisfaction) measures satisfaction with a specific interaction or feature. Both are useful: NPS for relationship health; CSAT for transaction quality.
Is NPS still relevant in 2026?
Yes, though debated. Critics argue NPS is too simple and culturally biased; advocates value its predictive power and simplicity. Modern practice combines NPS with qualitative analysis of the 'why' follow-up, usage data, and other retention signals.
How do I improve NPS?
Find Detractor root causes through follow-up calls. Address systemic issues (slow response, project delays, poor handover quality). Empower frontline teams to resolve customer issues. Close the loop with each respondent.
Can solar EPCs ask for referrals based on NPS?
Yes effectively. Promoters (9-10) are the prime referral pool. Quality EPCs invite Promoters to refer, often with incentives (discount on AMC, referral bonus). Detractors should not be asked for referrals until concerns are addressed.
What is closed-loop feedback?
Closed-loop feedback is the practice of contacting each NPS respondent to acknowledge their score, understand context, and act on feedback. Promoters get thanked and asked to refer; Passives get questioned about what would make them Promoters; Detractors get root-cause investigation and resolution.
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- Fred Reichheld. Original HBR article (2003), 'The Ultimate Question' book.
- Bain & Company NPS research.
- OpenView Partners SaaS NPS Benchmarks.
- Retently NPS benchmarks by industry.
- NSEFI customer satisfaction surveys.
- QuickEstimate internal NPS data. Solar EPC patterns.
- SaaStr NPS frameworks.
Written by QuickEstimate Editorial, QuickEstimate Editorial (Surat).
Last updated: 4 June 2026.