Generator Sizing Guide
Size it right the first time — with the interactive kW calculator.
Nine guides on backup power — sizing, ratings, fuels, emissions, buying used, and values — from the buyer behind the library.
Nine guides covering sizing, ratings, fuels, emissions tiers, buying used, load-bank testing, and values — written for facility managers, contractors, farmers, and anyone buying or selling backup power. From the buyer who buys and sells used generators.
Diesel or natural gas, running or not — send nameplate photos. Sell your generator →
Size it right the first time — with the interactive kW calculator.
The three ratings that decide what a generator is allowed to do.
Fuel choice: power density, storage, emissions, and the real trade-offs.
Tier 4 Final, the emergency exemption, and how to read the emissions label.
Model families, hour meters, what to inspect, and the 20–50 kW sweet spot.
Why generators need real load, wet stacking, and NFPA 110.
When the job outgrows diesel: gas turbines on the secondary market.
Diesel and natural gas — how to get today’s price from Ironcrest.
End of life: copper, steel, aluminum, and the engine’s core value.
Every generator follows the same arc: specified and sized (sizing guide), installed for a duty it was rated for (ratings), fueled and permitted (fuel choice, EPA tiers), maintained and load-tested through its service years (load banks), and eventually decommissioned — sold whole to its second owner (buying guide, sell yours), or parted and recovered (scrap values). At the top end of the scale, turbines take over (turbines guide). This hub follows that arc in order — wherever your generator is in its life, there is a guide for what comes next.
Every generator listing — dealer, auction, or Marketplace — should answer five questions: make and model (the family tells you parts availability), kW and rating (standby? prime? continuous? — the number without the rating is noise), fuel (diesel or natural gas), hours (and whether the meter is believable), and tier/emissions label (can it legally do your duty?). If a listing is missing two or more of these, the seller either does not know or does not want you to know — price the uncertainty in. The guides in this hub teach each one: the sizing guide for kW, ratings for duty, EPA tiers for legality, and the buying guide for the inspection. Sixty seconds, five questions, no surprises.
Generators are the most misunderstood equipment on the secondary market: mis-sized, mis-rated, mislabeled on listings everywhere. A “100 kW” listing that is really 80 kW prime. A Tier 2 unit that cannot legally run non-emergency. A 2,000-hour unit with a rolled-back meter. We buy and sell used generators, and we wrote these guides so both sides of the trade know what they are looking at. An informed seller photographs the nameplate; an informed buyer reads the rating, the tier, and the hours before the price. That is the whole market, and now you know it.
Nameplate (make, model, kW, serial), hour meter, and overall condition. The nameplate is the entire specification.
Call or text 312-880-8174 or use the quote form. Tell us the kW, fuel, hours, and condition.
A real offer based on your photos and today’s market — not a calculator, not a guess.
Every industry that depends on standby power buys generators on a cycle — and sells them on one too. These guides cover what each industry runs, the rules behind the purchase, and when their used units hit the market.
Sizing, validation rules, and when pharma plants sell their used units.
2–3.5 MW fleets, Uptime Tiers, and the decommissioning cycle.
NFPA 110 requirements, monthly testing, and the best-kept secret in used generators.
Up to 60 MW plants and why a blip costs millions.
FAA standby requirements and what airport fleets back up.
EPA resilience guidance and sizing for pumps that cannot stop.
Prime-power 500–2,500 kW skid units — where the generator IS the power.
The diesel backbone, and why the energy transition is retiring it early.
-48V DC plants, central offices, and the consolidation surplus.
Factory sizing, EPA tier rules, and the closure surplus cycle.
The complete hub — every guide in one place.
Related: data center power infrastructure, sell a used UPS system.
Size it right with the interactive calculator.
Diesel and natural gas — get today’s price.
Diesel or natural gas, running or parts — send photos for today’s price.
Our sister hub: breakers, panels, switchgear, transformers — and the buyers behind them.
Cat5e through Cat8, termination, and cable values — from the internet’s Cat cable buyer.
The 7 factors buyers actually use — hours, tier, documentation, and how to present yours.
Campus expansions and teardowns put generators on the market — approvals, sizing, removal.
Spoilage-proof standby, replaced on schedule — how food facilities sell their generators.
Upgrades, mergers, relocations — the straightforward path for facility managers and trustees.
Removal is half the job — disposition options and what affects decommissioned value.
What “near me” results actually show — and why a national buyer beats a local one.
Code-driven replacement, low hours, full records — and rooftop removal logistics.
24/7 cultivation loads on serious standby — when facilities upgrade or consolidate.