Methodology

Facts

Exam format, fees, eligibility, content weights and passing rules are taken only from the United States Environmental Protection Agency or a government/regulatory source. Each fact page lists its sources with the date we retrieved and last verified them. Sources are re-fetched on a schedule; when a source changes, dependent pages are flagged for human review and are not rewritten automatically.

Questions

Every question is originally authored by our team against the published content outline (blueprint 40 CFR part 82 subpart F, appendix D, section d). We do not use recalled exam items, question dumps, or other providers' banks. Each question stores its topic, difficulty, sources, author and reviewer. Questions marked draft are usable in practice but are not published as standalone pages until a reviewer approves them.

Readiness score

topic_mastery = recency- and difficulty-weighted correctness, shrunk toward 0.5 when fewer than three attempts exist. readiness = Σ(blueprint_weight × topic_mastery), shown 0–100. Bands: Strong ≥ 80, Developing 60–79, Needs focused review < 60. We deliberately do not publish a "pass probability"; we have no outcome data to calibrate one.

Study plan

priority(topic) = blueprint_weight × (1 − mastery) × urgency, where urgency rises for weak topics as the exam approaches. Weekly hours are allocated proportionally with 15% review + 10% mixed quiz (40% + 20% in the final week).

Practice selection

question_priority = weakness × blueprint_weight × time_since_last_seen × difficulty_fit. Questions seen in the last 24 hours are excluded.

Independence

EPA 608 Plan is an independent resource and is not affiliated with, endorsed by, or connected to the United States Environmental Protection Agency. Every regulatory figure on this site carries its CFR citation and is re-checked every 60 days against the eCFR. Questions are original and pending review by a certified HVAC technician. Nothing here is legal advice, and EPA-approved certifying programmes set their own fees and time limits.