Constellation vs IGS Energy: most-reported complaints compared
Most-reported issues at Constellation and IGS Energy, according to reviewers on Trustpilot — classified by our automated reader and backed by verbatim quotes from distinct reviews. This is a side-by-side of what reviewers report, not a score, rating or recommendation for either company.
Constellation
TrustScore 4.2 · 327 reviews on Trustpilot.
177 reviews analysed, 2026-04-30 to 2026-09-22.
Complaint rate (recent window): 15%
98% of negative reviews get a company reply.
“I apply for service and recieved nothing with out an explanation.”
IGS Energy
TrustScore 4.4 · 29,353 reviews on Trustpilot.
472 reviews analysed, 2026-06-11 to 2026-09-20.
Complaint rate (recent window): 12%
100% of negative reviews get a company reply.
“The rate jumped to 11 cents or something ridiculous.”
Reported on both
Issues with an evidenced category (at least two verbatim quotes) on both sides.
| Issue | Constellation | IGS Energy |
|---|---|---|
| Other | 18% | 24% |
| Billing errors | 11% | 8% |
| Misleading pricing | 11% | 36% |
Method: reviews are classified into a fixed complaint taxonomy by an automated reader; every category shown is backed by at least two verbatim quotes from distinct reviews. Figures are census classifications, not official statistics, and reflect what reviewers reported — not findings of wrongdoing by either company. Not affiliated with, endorsed by, or sponsored by Trustpilot A/S, Constellation or IGS Energy.