Generator shopping tends to happen under time pressure, usually with a storm forecast already on the news. Working through sizing, safety, and installation questions ahead of time, while the power is still on, produces a much better outcome than making decisions in a parking lot the day before landfall. Here are seven free resources worth bookmarking now.
1. Electrical Power Calculator
This free tool handles the running-versus-starting watt math that trips up most generator shoppers, converts between watts, amps, and volts for single and three-phase setups, and includes a dedicated motor-starting mode for appliances like sump pumps and well pumps. Building an appliance list against real numbers here, before you're standing in a store aisle, removes most of the guesswork from the purchase.
It also handles the kW-to-kVA conversion that trips up shoppers comparing a portable unit against a whole-house standby system, since those two categories are frequently rated in different units on their spec sheets.
2. Ready.gov Power Outage Guidance
Ready.gov is FEMA's public preparedness site, and its power outage section covers generator placement safety, carbon monoxide risk, and food safety during extended outages. It's a good gut check on the non-electrical parts of outage planning that are easy to overlook when you're focused entirely on wattage math, including how long refrigerated and frozen food actually stays safe once the power goes out.
3. NFPA National Electrical Code Resources
The NFPA maintains the National Electrical Code that governs how generator inlets, transfer switches, and interlock kits are supposed to be installed. You won't need to read the full code to plan a purchase, but knowing an installation has to meet a real published standard is useful context before hiring an electrician or attempting a DIY transfer switch setup, and it's worth asking any electrician you hire to confirm the installation meets current code rather than assuming it automatically does.
4. OSHA Portable Generator Safety Guidance
OSHA publishes portable generator safety material aimed at worksites, but the carbon monoxide, backfeed, and wet-conditions warnings apply just as directly to home use. It's a concise reference for the failure modes that cause injuries every storm season, most of which have nothing to do with sizing and everything to do with placement and wiring, including running a generator in a garage with the door partly open, which is a common and genuinely dangerous mistake despite feeling like a reasonable compromise.
5. U.S. Department of Energy Backup Power Guidance
The Department of Energy has consumer-facing material comparing portable generators, standby generators, and battery backup systems, along with efficiency and fuel-type considerations. Useful if you're deciding between a portable unit and a permanently installed standby system rather than assuming portable is automatically the right call, particularly if your area experiences multi-day outages often enough that a permanent installation might make more sense long term.
6. UL Certification Lookup
UL certifies generators and related electrical equipment for safety, and checking whether a specific model carries UL listing is a quick way to filter out questionable off-brand units before you've spent any money. A missing certification on an otherwise cheap generator is worth treating as a real red flag rather than a minor detail, since certification testing covers things like overload protection and insulation integrity that aren't obvious from a product listing photo.
7. Consumer Reports Generator Testing
Consumer Reports independently tests portable and inverter generators for real-world wattage delivery, noise levels, and runtime, which sometimes differs meaningfully from manufacturer marketing claims. Cross-referencing a shortlist against their testing data before buying can save you from a unit that underperforms its printed spec once it's actually under load, particularly on the surge-watts figure, which is the number most prone to optimistic rounding on a spec sheet.
How to Prioritize These If You're Short on Time
If a storm is already in the forecast and you don't have time to work through all seven, start with the calculator to get a real target wattage, then check Ready.gov for placement and carbon monoxide safety before you set anything up in the garage or driveway. Those two alone cover the most consequential mistakes: buying the wrong size and running the unit somewhere dangerous.
If you have more lead time, work through the rest in order. NFPA and UL matter most before a purchase, since they affect which specific unit and installation method you choose. OSHA and Consumer Reports matter most after you've narrowed down a shortlist, since they help you compare specific candidates against real safety and performance data rather than marketing claims alone. DOE's comparison material is most useful earlier in the process, when you're still deciding between a portable unit, a standby system, or a battery backup rather than assuming portable is automatically right.
What Each Resource Doesn't Cover
Worth being honest about the gaps too. The calculator handles wattage, amperage, and voltage math but says nothing about placement safety or carbon monoxide risk, which is why Ready.gov and OSHA are on this list in the first place rather than being redundant with it. NFPA's code documents are written for professionals installing equipment, not homeowners comparing purchase options, so they're a reference to have on hand rather than something to read cover to cover before buying anything.
UL certification tells you a unit met a safety standard during testing; it doesn't tell you whether that specific unit is well suited to your household's appliance list, which is a sizing question the certification doesn't address at all. Consumer Reports and DOE both help with comparing options, but neither replaces working out your own actual peak wattage requirement first, since a well-reviewed generator that's simply the wrong size for your appliances doesn't become the right size because it tested well in someone else's review.
Why It's Worth Doing This Before, Not During, a Storm
Every one of these resources takes longer to use well under time pressure than it does with a calm afternoon and a cup of coffee. Reading OSHA's placement guidance while a generator is already running in the wrong spot doesn't help as much as reading it before you've set anything up. Comparing Consumer Reports data while standing in a store aisle with a limited selection isn't as useful as narrowing a shortlist ahead of time, when every option is still available online.
Putting These Together
None of these seven resources replace the others. The calculator handles your specific appliance math, Ready.gov and OSHA cover the safety side, NFPA and UL cover the standards and certification side, and DOE and Consumer Reports help with the actual purchase decision. Working through all seven once, well before a storm is on the forecast, turns generator shopping from a panic decision into a five-minute confirmation of a plan you already made.
Bookmarking these now costs nothing. Looking them up for the first time during an active outage, on a phone with a dwindling battery and no reliable signal, costs a lot more than the ten minutes it takes to read through them today while the power is still on and the wifi still works.
For the full sizing methodology, including a worked example with real running and starting watt numbers, see How to Size a Backup Generator Before the Next Outage.
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