Home Generators and Backup Power: 4 Categories, Real Costs, No Rankings

Home generators and backup power systems fall into four distinct categories, but most buying guides only cover one or two. That gap costs homeowners money. Portable generators cause an average of 73 carbon monoxide poisoning deaths per year (CPSC, 2015-2020), and the advertised price on the box rarely matches the real build cost once required accessories are added. A generator advertised at $599 costs $919 after the transfer switch and cord that are not in the box. This page compares all four backup power categories side by side: portable generators, standby generators, portable power stations, and home battery systems.

No rankings. No picks. Every category has a use case, and every use case has a price tag that includes the parts the manufacturer leaves out of the box. The data below covers running watts, starting watts, real build costs, fuel burn rates, noise levels, and runtime calculations across 7 specific products tracked in the OffGridEmpire database.

Prices checked Apr 5, 2026. Current prices may differ.

Use the backup power calculator to size your specific load before comparing categories. Browse 301 portable power stations with real build costs for every unit.

Step 1: Calculate Your Actual Load

Starting watts versus running watts is the number one sizing mistake in backup power. A full-size refrigerator draws 150W while running, but its compressor pulls 1,200W at startup. Buying a generator rated for running watts alone means the unit stalls the moment a motor kicks on. Every motor-driven appliance (refrigerators, sump pumps, furnace fans, air conditioners) draws 2-3x its running wattage during startup surge.

Common Appliance Wattage Reference

Load Example 1: Basics Only

Fridge + sump pump + lights = 1,250W running. The sump pump surges to 2,100W at startup. This load requires a generator rated for 2,000W+ starting watts or a portable power station with 1,500Wh+ capacity. The Champion 100692 (1,700W running, 2,000W starting) barely covers this scenario with zero margin for the sump pump surging while the fridge compressor cycles on.

For a battery-based approach, the EcoFlow DELTA 3 Max (2,048Wh, 2,400W inverter) handles the 1,250W running load and provides approximately 13 hours of runtime (2,048 x 0.80 / 1,250). No fuel, no exhaust, no transfer switch required. The smaller EcoFlow DELTA 3 Plus (1,024Wh, 800W inverter) cannot handle this load. Its 800W inverter is 450W short of the 1,250W running demand.

Load Example 2: Comfort Load

Add a furnace fan and TV to the basics: 2,800W running, 4,450W surge if the furnace fan and sump pump start simultaneously. This requires a 5,000W+ generator. The Champion 100692 cannot handle this load. Its 2,000W starting ceiling is 2,450W short of the combined surge. No portable power station in the OffGridEmpire database handles this surge either. The EcoFlow DELTA 3 Max inverter (2,400W) covers the running watts but not the simultaneous startup surge of two motor-driven appliances.

The rule: size for surge watts, not running watts. A unit rated at 3,600W running but 4,650W starting (like the Westinghouse WGen3600DF) covers comfort loads with margin. A unit rated at 1,700W running (like the Champion 100692) does not. The Westinghouse WGen3600DF also runs for 14 hours on its 4-gallon tank, long enough to cover most regional outages.

Use the OGE calculator to input your specific appliances and get exact sizing. Compare generators and power stations side by side with real build costs.

Portable Generators: High Power, Real Costs

The Westinghouse WGen3600DF costs $599 on the product page. It costs $919 to actually connect to a home. The difference is $320 in required missing parts: a transfer switch and power cord that are not in the box but are legally required for home circuit connection.

Portable generators are open-frame gasoline or dual-fuel units producing 1,700W to 13,000W. They are the loudest backup power category at 68-74 dBA and the only category that produces carbon monoxide exhaust. Dual-fuel models (like both Westinghouse units in this comparison) run on gasoline or propane, providing fuel flexibility during shortages when gas station pumps lose power. Single-fuel gasoline models carry a lower listed price but are limited to one fuel source that requires stabilizer for long-term storage.

Advertised Price vs. Real Build Cost

Every portable generator in this table is 70% complete out of the box. The remaining 30% is the transfer switch, power cord, and associated hardware required to legally and safely connect the generator to home circuits.

Inverter Generators

Inverter generators produce cleaner power output (pure sine wave) safe for sensitive electronics. They run quieter at 48-57 dBA compared to conventional portable generators at 68-74 dBA. The tradeoff is capacity: most inverter models max out at 2,000-3,500W, and they cost more per watt than conventional open-frame units. The Champion 100692 is an inverter model: 1,700W running, 2,000W starting, 53 dBA, 39 lbs, with a runtime of 11.5 hours on its 1.05-gallon tank at 25% load.

Carbon Monoxide: The Risk Nobody Reads About Until It Happens

CPSC data shows 73 carbon monoxide poisoning deaths per year from portable generators (2015-2020 average). The CPSC 2023 rule now requires new portable generators to auto-shutoff when CO reaches unsafe indoor levels. The placement rule is non-negotiable: 20+ feet from the home with exhaust aimed away from all windows and doors.

During Hurricane Idalia, a homeowner placed a generator outdoors following guidelines. Wet, humid air pushed exhaust back toward the house. The CO detector alarmed. The homeowner switched to a solar and battery system afterward. Outdoor placement reduces risk but does not eliminate it in all weather conditions.

Noise in Context

A conventional portable generator at 68 dBA is equivalent to a loud conversation. At 74 dBA, it matches a lawnmower. HOA noise restrictions commonly cap sustained outdoor noise at 55-65 dBA, which rules out every conventional portable generator and permits only inverter models or portable power stations. The Champion 100692 at 53 dBA passes most HOA thresholds. The Westinghouse WGen3600DF at 68 dBA does not.

Browse all tracked generators with real build costs on the comparison tool. View individual kit breakdowns for component-level pricing.

Standby Generators: Whole-Home Power at a Premium

A Generac 22kW standby generator burns 2.53 gallons per hour of propane at 50% load. That number does not appear on the product page, in most reviews, or in dealer quotes. It determines whether a 500-gallon propane tank lasts 4 days or 10. At propane prices of $2.50-$3.50/gal, that 22kW unit costs $6.33-$8.86/hr to run, or $152-$213/day at 50% load.

Standby generators are permanently installed units that run on natural gas or propane. They detect a power outage via an automatic transfer switch and start within 10-30 seconds with no manual intervention. Output ranges from 10 kW to 26 kW, enough to cover central air conditioning.

Installed Cost

A Generac 22kW unit costs $5,500-$7,000 for the generator alone. Fully installed, the total reaches $8,000-$16,000. Installation includes a concrete pad, automatic transfer switch (ATS), gas line extension, electrical permit, and licensed electrician labor. The spread depends on local permit costs, gas line distance, and contractor rates. A 10kW unit (sufficient for fridge + sump pump + furnace fan + lights) installs for $5,000-$8,000, roughly half the cost of a 22kW whole-home system.

Fuel Consumption: Generac Propane Data

Runtime by Tank Size

Natural gas connections provide theoretically unlimited runtime. The caveat: widespread emergencies can cause gas pressure drops across the distribution network. During the 2021 Texas winter storm, natural gas pressure dropped across the state grid, shutting down gas-fired generators at the moment they were needed most. Propane tanks do not depend on pipeline pressure.

Maintenance

Standby generators require annual maintenance: oil change, air filter, spark plugs, and a load test. Most manufacturers recommend professional servicing every 200 hours of operation or once per year, whichever comes first. Annual service contracts run $200-$500. The unit also runs a weekly self-test cycle (typically 15-20 minutes) to keep the engine lubricated and verify functionality.

Standby generators fit homeowners who need central AC coverage, have medical equipment on continuous power, or cannot tolerate manual switching. The minimum budget is $8,000 installed. OffGridEmpire does not track standby generators as individual kits due to the variable installation cost component.

Use the calculator to determine whether your load actually requires standby-level output. Explore whole-home backup options.

Portable Power Stations and Home Batteries: Silent, Safe, Finite

The EcoFlow DELTA 3 Max costs $799 advertised and $799 real build cost. Zero required missing parts. The Westinghouse WGen3600DF costs $599 advertised and $919 real build cost. The power station is $200 more on the shelf and $120 less once everything needed to use it is accounted for.

Portable power stations are all-in-one LiFePO4 battery and inverter units. No fuel. No exhaust. No carbon monoxide. Noise output ranges from 30-50 dBA (quieter than a refrigerator). They are safe to operate indoors, in a garage, or in a bedroom closet.

Runtime Formula

Hours = Wh x 0.80 / Device watts

The 0.80 factor accounts for inverter efficiency loss (source: EcoFlow engineering). Every watt-hour rating on a spec sheet is the battery's stored energy; roughly 20% is lost during DC-to-AC conversion.

Worked Runtime Examples: Full-Size Refrigerator (150W Running)

The real build cost advantage is direct. Every portable power station tracked on OffGridEmpire ships complete: advertised price equals real build cost. Generators require $250-$550 in transfer switches, cords, and hardware before they can connect to home circuits. Power stations also recharge from solar panels, a standard wall outlet, or a car's 12V port, adding flexibility that generators lack entirely.

Inverter Capacity Matters

The inverter wattage determines the maximum simultaneous load a power station can handle. The EcoFlow DELTA 3 Plus has a 800W inverter. That limits it to devices drawing 800W or less, which excludes sump pumps (800W running, 2,100W surge). The EcoFlow DELTA 3 Max at 2,400W handles sump pumps, space heaters, and multiple appliances simultaneously. The Bluetti AC180T at 1,800W falls between the two. Check inverter wattage against your surge load, not just battery capacity against your runtime needs.

Home Battery Systems

Home batteries scale the portable power station concept to whole-home capacity. The Anker SOLIX 18kWh stores 18,000Wh of LiFePO4 energy at an advertised price and real build cost of $8,299 (complete, zero required missing parts). The kit includes a 400W solar panel for daytime recharging.

Runtime at a combined critical load of 450W (fridge + lights + router): 18,000 x 0.80 / 450 = 32 hours. At the lighter load of fridge + lights only (~200W), runtime extends to 72 hours. Paired with the included solar panel, a home battery system can provide indefinite runtime during daylight recharging cycles.

20-Year Lifecycle Cost

EnergySage 2026 data puts the numbers in perspective:

• Gas generator system: $91,319 over 20 years (purchase + fuel + maintenance). That is $4,566/year.
• Solar + battery system: $60,961 over 20 years (purchase, zero fuel). That is $3,048/year.

The battery system costs 33% less over its lifetime, a difference of $30,358 over 20 years. The gap comes from compounding fuel and maintenance expenses on the generator side versus zero-fuel operation on the battery side. Generator fuel costs increase with energy prices; battery operating costs do not. LiFePO4 batteries are rated for 3,000-5,000 charge cycles before degrading to 80% capacity, which translates to 8-14 years of daily cycling.

Browse all 301 portable power stations with real build costs. Compare any two units side by side. Read the portable power station guide for deeper technical breakdowns. Explore home battery systems.

Transfer Switches: The Cost Every Generator Guide Skips

Transfer switches add $25 to $2,000 to every generator system. Without one, the only way to connect a portable generator to home circuits is backfeeding: pushing power backward through the electrical panel. Backfeeding is illegal in all US jurisdictions and can electrocute utility linemen working to restore power on the same transformer.

Three Types of Transfer Switch

Interlock kit: $25-$200. A mechanical bracket installed on the breaker panel that physically prevents the main breaker and generator breaker from being on simultaneously. DIY installable in most jurisdictions. Manual operation required during each outage. Must be matched to the specific breaker panel brand and model.

Manual transfer switch: $200-$600 total (unit + $300-$500 electrician labor). A dedicated subpanel with pre-wired critical circuits. The homeowner flips a single switch to transfer from grid to generator power. Requires a licensed electrician for installation.

Automatic Transfer Switch (ATS): $600-$2,000+ total. Auto-detects an outage, auto-starts the generator, and auto-reverses when grid power returns. Standard on all standby generator installations. The most expensive option but requires zero manual intervention.

Real Build Cost Impact by System

Portable power stations plug directly into appliances or wall outlets (via the outlet, not the panel). No transfer switch. No electrician. No permit. This is the single largest reason the real build cost gap between generators and power stations is smaller than the advertised price gap suggests. Factor the transfer switch into the budget before comparing generator prices to power station prices.

Compare real build costs across all categories. View component-level kit breakdowns.

How to Choose: Decision Framework by Outage Type

Most homeowners default to a portable generator because it is the only category they have heard of. Four categories exist, and the right one depends on four variables. The questions below are ordered by priority: outage duration eliminates categories first, then critical load narrows the remaining options, then budget and constraints finalize the decision.

Question 1: How Long Are Your Outages?

• Under 8 hours: Portable power station. A 1,024Wh unit covers fridge + lights for the duration.
• 8-48 hours: Portable generator or large power station (2,048Wh+).
• 2-7 days: Standby generator or home battery + solar panels.
• 7+ days: Standby generator with a 500-gallon propane tank.

Question 2: What Is Your Critical Load?

• Fridge + lights + phones (~500W): Power station at $699-$999 real build cost.
• Add sump pump + furnace fan (~2,000W): Mid-range generator at $919 real build cost or 2,400W power station at $799.
• Add central AC (10,500W surge): Standby generator only at $8,000-$16,000 installed.

Question 3: What Is Your Budget?

• Under $1,000: EcoFlow DELTA 3 Plus ($699 real build cost, 1,024Wh), EcoFlow DELTA 3 Max ($799 real build cost), or Westinghouse WGen3600DF ($919 real build cost).
• $1,000-$3,000: Large power station + solar panels, Bluetti AC180T ($999 real build cost), or Westinghouse WGen9500DF ($1,549 real build cost).
• $3,000-$10,000: Anker SOLIX 18kWh ($8,299) or entry-level standby generator.
• $10,000+: Standby generator fully installed.

Question 4: Noise and Safety Constraints?

• HOA restrictions, indoor use, or zero CO risk required: Portable power station only (30-50 dBA).
• Neighbors close but outdoor use acceptable: Inverter generator (53 dBA) or power station.
• Rural property, no restrictions: Any category works. Prioritize by outage duration and budget.

Summary: 4 Categories at a Glance

Use the calculator to input your specific appliances. Compare real build costs for any two systems. Browse all 301 tracked power stations.

The Numbers Say

Three data points change the backup power decision for most homeowners.

Real build cost changes the math. The Westinghouse WGen3600DF advertises at $599 but costs $919 in real build cost. The EcoFlow DELTA 3 Max advertises at $799 and costs $799 in real build cost. Comparing advertised prices makes the generator look $200 less. Comparing real build costs makes the power station $120 less. Compare real build costs, not advertised prices.

Most homeowners overbuy. For outages under 12 hours with fridge + lights + phones, an $799 power station covers it silently, indoors, with zero fuel logistics. A $919 generator adds fuel storage, CO risk, outdoor placement requirements, and a transfer switch.

Only central AC forces the generator decision. A 3-ton central air conditioner surges to 10,500W at startup. No portable power station handles that. Only a standby generator ($8,000-$16,000 installed) or a home battery system paired with solar covers central AC. If central AC is not on the critical load list, the generator requirement disappears for most households.

No recommendation. Use the calculator to size your load, then compare real build costs across categories. Browse all 301 tracked portable power stations.

FAQ

What size generator do I need to run my house?

Size for starting watts (surge), not running watts. Critical circuits (fridge + sump pump + furnace fan + lights) need approximately 1,250W running but 2,350W surge at peak. A 3,600W+ generator handles this with margin. Adding central air conditioning requires 10,500W surge, which only a standby generator (10 kW+) covers. Use the OGE calculator for exact sizing based on your specific loads.

Can a portable power station replace a generator for home backup?

For outages under 12 hours with critical loads (fridge, lights, phones, router), yes. The EcoFlow DELTA 3 Max (2,048Wh) runs a full-size refrigerator for 10.9 hours (2,048 x 0.80 / 150W). The Bluetti AC180T (1,433Wh) provides 7.6 hours of fridge runtime at a $999 real build cost. For multi-day outages or loads above 2,400W, a generator or home battery system is necessary.

How long will a portable generator run on a tank of gas?

Depends on generator size and load. The Westinghouse WGen9500DF runs 12 hours on its 6.6-gallon tank at 50% load. A standby Generac 22kW burns 2.53 gal/hr propane at 50% load; a 500-gallon tank lasts approximately 4 days. A 100-gallon tank with a 10kW standby unit provides roughly 24 hours.

Do I need a transfer switch for a portable generator?

Yes, for both safety and legality. Without one, connecting a generator to home circuits requires backfeeding through the panel, which is illegal in all US jurisdictions and can electrocute utility linemen working to restore power. Interlock kits start at $25; manual transfer switches cost $200-$600 installed. Every generator in the OffGridEmpire database includes transfer switch cost in its real build cost.

Are portable generators safe to use during a power outage?

Only outdoors, positioned 20+ feet from the home with exhaust aimed away from all windows and doors. CPSC data: 73 CO poisoning deaths per year from portable generators (2015-2020 average). CPSC 2023 rules require new portable generators to auto-shutoff when CO reaches unsafe levels, but placement remains the primary risk factor. Portable power stations produce zero CO and operate safely indoors.

What is cheaper over 20 years: a generator or solar with batteries?

Solar + battery: $60,961 over 20 years ($3,048/year). Gas generator system: $91,319 ($4,566/year) per EnergySage 2026 data. The battery system costs 33% less over its lifetime. The generator's higher 20-year cost comes from compounding fuel and maintenance expenses that increase with energy prices.