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Generators & Backup Power guides

Sizing a generator, transfer switches, fuel types, and battery backup for keeping the lights on.

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0122 guides

Sizing & Choosing

Running Two Generators in Parallel: What Works and What Doesn't

You can connect two generators together only when both are parallel-capable inverter generators from the same maker, joined with that maker's parallel cable or kit. Two 2,200 W units become roughly 3,600 W of continuous 120 V power through a 30 A outlet. Conventional generators cannot be paralleled by a homeowner, and two 120 V units don't make 240 V.

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RV and Camping Generators

The RV air conditioner decides generator size: a 13,500 BTU unit needs roughly 2,800–3,000 starting watts and 1,300–1,800 running, which is why 3,000–3,500 W inverter generators dominate. Everything else in an RV runs on comparatively little.

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RV Surge Protector vs EMS: Which One Do You Need?

A basic RV surge protector absorbs voltage spikes and nothing else. An electrical management system does that and also checks the pedestal before connecting, then cuts power on open ground, open neutral, reversed polarity, and voltage outside roughly 104 to 132 V, which is what actually kills RV air conditioners. Buy the one that matches your RV's shore cord: 30 A or 50 A.

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What Is an Inverter Generator? How It Works & When to Buy One

An inverter generator produces AC, converts it to DC, then inverts it back to a clean sine wave, which is why it can safely run laptops and electronics that a conventional generator can damage. It also throttles the engine to match load, making it markedly quieter and more fuel-efficient at partial load.

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Dual Fuel Inverter Generator: How They Work

A dual fuel generator runs on either gasoline or propane, which mainly buys you fuel-storage flexibility: propane keeps indefinitely, gasoline degrades in months. Expect roughly 10% less output on propane: the trade for fuel that is still good next winter.

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Generator Brands: How to Compare Them

For a standby generator the dealer and service network matters more than the spec sheet; an unrepairable unit is worse than none. For portables, compare engine sourcing and parts availability, noise rating in dBA, inverter capability, and warranty terms.

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What Size Generator to Run a Sump Pump?

A 1/3 to 1/2 HP sump pump draws roughly 600–1,050 W running and 1,800–3,000 W starting, so the surge sets the requirement. The pairing matters because the storm that floods a basement is usually the same weather event that cuts the power.

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Sizing a Generator for a Well Pump

A 1/2 HP submersible well pump needs about 900–1,200 W running and 2,000–3,000 W starting; a 1 HP unit roughly doubles that. Because the starting surge dominates, a rural home usually needs a 5,000–7,500 W generator, or a soft starter to bring the surge down.

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Generator Noise Levels: What the dB Rating Means

Generator noise is measured in dBA at a stated distance, and a 10 dB difference is roughly twice as loud. Inverter generators typically run 50–60 dBA against 70–80 for a conventional unit of similar output, because they throttle the engine to match load instead of running at fixed RPM.

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What Size Generator to Run a 1,500 Sq Ft House?

A 1,500 sq ft house needs roughly 5,000–7,500 running watts to cover essentials, or a 12–16 kW standby generator to run the whole house including central AC. Square footage sets the ballpark because it predicts your AC size; the actual number comes from your running load plus the largest single motor surge.

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What Size Generator for a 2,000 Sq Ft House? Sizing and Cost

A 2,000 sq ft house typically needs 6,500–9,500 running watts for essentials, or a 16–22 kW standby generator to run the whole house including central air conditioning. The jump over a smaller home comes almost entirely from the larger AC compressor's starting surge, not from the extra floor area.

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What Size Generator Do I Need? Sizing by Load and Surge

Size a generator by adding the running watts of everything you need at once, then adding the single largest starting surge, not the sum of all surges, since motors rarely start together. Add about 25% margin and round up to the next standard size.

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Portable vs Standby Generator: Which Should You Buy?

A portable generator costs $500–$2,500, must be rolled out, fuelled and connected manually, and runs the circuits you choose. A standby unit costs $4,000–$8,000 plus $3,000–$6,000 installed, runs on natural gas or propane, and starts automatically within seconds of an outage.

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Starting Watts vs Running Watts

A fridge that runs on 200 watts can demand 1,200 for a second. Sizing to the running number is how generators end up too small.

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What Can a Generator Run? By Wattage

What a generator runs is set by its continuous watts, but what it can start is set by surge capacity: motors draw roughly three times running watts for a second or two. A 5,000 W unit typically covers a fridge, furnace blower, sump pump and lights, but not central AC.

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Best Solar Generators for Home Backup

A solar generator is a battery, an inverter and a solar charge controller in one box. Which one is right is decided by two numbers: the inverter's continuous watts (can it start your load at all) and usable watt-hours (how long it runs). Everything else is secondary.

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Best Whole House Generator: How to Choose the Right Size and Type

A whole house generator is sized by the loads you actually need, not by the size of the house. Load management changes the math: shedding the two biggest intermittent loads routinely drops the required generator by a full size class, and the install is usually a larger line item than the generator itself.

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8 Generator Sizing Mistakes

The two mistakes that undersize a generator are ignoring starting surge and forgetting the well or sump pump; the two that oversize it are adding every appliance surge together and sizing to the panel rating. The correct method is running watts plus the single largest surge, plus about 25%.

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Running Sensitive Electronics on a Generator

A conventional generator produces a rougher waveform with higher total harmonic distortion, typically above 5%, while an inverter generator delivers under 3%, close to grid quality. Motors and heaters tolerate the difference; laptops, variable-speed HVAC boards and modern appliance electronics may not.

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Solar Generator vs Gas Generator

A "solar generator" generates nothing; it is a battery with an inverter, recharged from solar or an outlet. That reframes the comparison: a gas generator makes power continuously while fuel lasts; a battery delivers stored energy silently and indoors, then needs recharging.

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Whole-House vs Essential-Circuits Backup

True whole-house backup requires a generator sized for every load simultaneously, including central AC and the range. Most systems marketed as whole-house use load management to shed circuits instead, which is the smarter design, and far cheaper than sizing for a peak that never occurs.

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Running a Furnace on a Generator

A gas furnace mostly burns gas. The electricity is for the blower and controls, which makes it one of the cheapest loads to back up.

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0213 guides

Installation & Transfer Switches

Generator Neutral Bonding: Bonded vs Floating Neutral

The bond must exist exactly once in the system. Whether the generator provides it depends entirely on what the transfer equipment does with the neutral.

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Transfer Switch Explained

A transfer switch has one job: make it physically impossible for utility power and generator power to reach the house at the same time. Everything else (automatic starting, load shedding, circuit selection) is convenience layered on that single safety function, required by NEC 702.5.

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Generator Inlet Box: What It Is and Why You Need One

A generator inlet box is a weatherproof flanged inlet, a recessed male connector, mounted outside and wired to your transfer equipment. It is what lets the cord connect outside with no exposed live prongs anywhere, and it keeps the generator at a safe distance from the house.

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Interlock vs Transfer Switch: Which Generator Connection to Use

An interlock kit is a sliding plate that makes it physically impossible to have the main breaker and the generator breaker on at once: cheap, and it gives you access to every circuit. A transfer switch is a separate box wired to selected circuits, faster to operate and available in automatic form.

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How to Hook Up a Generator to Your House (Safely and Legally)

There are three legal ways to hook up a generator to a house: a manual or automatic transfer switch, a listed interlock kit on the panel, or a generator inlet box feeding one of those. What is never legal is a double-male "suicide cord" into an outlet: it energizes the utility line and can kill a lineworker.

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Backfeeding a Generator: Why the Suicide Cord Kills

Back-feeding a house through a double-male cord into an outlet energises the utility transformer in reverse, putting distribution voltage on lines a crew may be working on, and leaving live exposed prongs on the other end of the cord. NEC 702.5 requires transfer equipment precisely to make this impossible.

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Generator Electrical Requirements

A generator connection needs a weatherproof inlet box, transfer equipment (interlock or transfer switch) per NEC 702.5, a feeder sized to the generator output, and correct neutral bonding: bonded or floating must match the transfer method under NEC 250.30 and 250.34.

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Generator Pad and Mounting

A standby generator needs a level pad (poured concrete or a composite pre-cast) sized larger than its footprint, above expected flood and snow-drift level, with manufacturer clearances maintained. Level matters most: lubrication and fuel systems assume it, and running out of level accelerates wear.

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Generator Permits and Inspection

Connecting a generator to house wiring requires an electrical permit in essentially every jurisdiction, and gas or zoning permits often follow. The inspection is also the only independent check that the transfer equipment, neutral bonding and conductor sizing were done correctly.

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Generator Placement and Clearances

A portable generator belongs at least 20 feet from the house with the exhaust pointed away from doors, windows and vents, never in a garage, even with the door open. Standby units follow manufacturer and NFPA 37 clearances, commonly 5 feet from openings and 18 inches from walls.

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Manual vs Automatic Transfer Switch

A manual transfer switch requires someone present to operate it and takes minutes; an automatic transfer switch senses the outage, starts a standby generator and switches in 10–30 seconds unattended. The deciding question is what happens if the power fails while nobody is home.

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Standby Generator Installation Cost: What Drives It

A home standby generator runs roughly $4,000–$6,000 for an air-cooled unit plus $3,000–$6,000 installed. The line items that blow budgets are gas supply (an existing meter often cannot feed the generator plus the furnace and range) and placement clearances forcing a longer run.

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Standby Generator Installation: The Process

The physical installation is one to two days: pad, generator set, transfer switch, gas line and electrical connections. The project runs three to eight weeks, because permitting, gas utility scheduling and inspection sit around it, and the gas work is often the long pole.

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0318 guides

Fuel & Running Cost

Generator Breaker Keeps Tripping: Overload, Short or Fault

A generator breaker that keeps tripping is usually telling you the truth: the load is bigger than the outlet or the generator can carry, often because a motor's starting surge was never counted. Work out which device tripped, unplug everything, and add loads back one at a time with a clamp meter. A breaker that trips with nothing plugged in means a fault inside the generator.

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Generator Maintenance Schedule

Portable generators need an oil change every 50–100 run hours, annual air filter and spark plug, and monthly exercise under load. Standby units add an annual battery replacement: a dead starting battery is the number one reason a standby fails when it is finally called on.

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Generator Won't Start? Troubleshooting in Order

Work the list in order: fuel valve open, choke set correctly, oil level adequate, fuel fresh, battery charged. Stale gasoline and a dead battery between them explain most no-start calls, and both are entirely preventable with stabiliser and an annual battery replacement.

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How to Charge a Generator Battery: Portable and Standby

Electric-start generators run on a small 12 V battery that self-discharges while the generator sits. Most portables only charge it while the engine runs, and standby units need utility power to run their built-in charger. A 1–2 A smart charger or maintainer, connected positive then negative, keeps either one ready.

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Why Is My Generator Surging: Causes and Fixes, Easiest First

Surging, or hunting, is engine speed rising and falling on its own while the lights pulse. On a portable that has been stored, a lean carburetor from stale fuel is the usual cause. Rule out the easy checks and eco mode first, and leave the governor to a service shop.

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Storing Gasoline for a Generator

Untreated E10 gasoline degrades in 1–3 months, and stale fuel is the single most common reason a portable generator will not start when needed. Stabiliser extends it to 12–24 months; propane stores indefinitely, which is the main argument for a dual fuel unit.

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Generator Extension Cords: Gauge, Length, and Safety

Generator cords must be sized for both load and length: 12 AWG carries 15 A to 50 feet, 10 AWG holds it to 100. Undersized cord means voltage drop, and low voltage is exactly why a refrigerator compressor fails to start and overheats trying.

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Generator Fuel Types: Natural Gas vs Propane vs Gas vs Diesel

Natural gas is piped and never runs out but depends on the utility; propane stores indefinitely in your own tank; gasoline is available anywhere but degrades in months; diesel is efficient and long-lived but costlier. Standby units run gas or propane, portables typically gasoline or dual fuel.

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Natural Gas vs Propane Generator

Natural gas is piped continuously and never needs refilling, but it depends on utility supply and requires an adequately sized gas line. Propane sits in your own tank and stores indefinitely, at the cost of refills and roughly 10% lower generator output than gasoline.

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Generator Running but No Power: Troubleshooting in Order

When the engine runs but nothing gets power, work from the generator outward: its own breakers and GFCI outlets, the mode switches, the cord, the transfer switch. Only if the generator's own outlets stay dead with everything reset is it an alternator problem, and that's service work.

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Propane Tank Sizing for a Generator

Tank size sets runtime, but in cold weather the vaporisation rate limits you before the fuel does: a small tank cannot boil off propane fast enough to feed a generator at full load. A 250–500 gallon tank is typical for a home standby unit, sized for both capacity and draw rate.

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Generator Carbon Monoxide Safety

Carbon monoxide has no smell and no colour, and a generator produces vastly more of it than a car. Most deaths happen in garages and basements with the door open.

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How Much Does It Cost to Run a Generator?

A portable generator burning 0.5 gal/hr at $3.50 costs $1.75 an hour, and at 2.5 kW output that is about $0.70 per kWh, roughly four times a typical utility rate. Acceptable for an outage, a poor plan for anything routine.

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Generator Exercise Mode: Why Standby Units Run Weekly

A standby generator self-exercises weekly for 10–20 minutes to keep the battery charged, circulate oil and reveal faults before they matter. A portable needs the same discipline manually: about 20–30 minutes monthly, and under real load rather than at idle.

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Running a Generator in Rain and Snow

Outages happen in bad weather. The generator still has to be outside: the answer is a cover designed for running, not a different location.

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Generator Oil Change: Intervals and Viscosity

Small engines hold very little oil (often under a quart) and run hard under continuous load, so the first change comes after about 20–25 hours of break-in, then every 50–100 hours. During a multi-day outage that interval arrives within days, not seasons.

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How Long Does a Generator Run on a Tank of Fuel?

A portable generator typically runs 8 to 12 hours on a full tank at half load, and manufacturer runtime figures almost always quote a 25% load, so real runtime under a working load is shorter than the box says.

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How Much Gas Does a Generator Use? Consumption by Size and Load

A portable generator burns roughly 0.5 to 0.75 gallons per hour at half load for a mid-size unit, and consumption scales with load rather than with the generator’s rating, which is why an oversized generator lightly loaded wastes fuel.

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0413 guides

Battery Backup

Battery Backup for a Furnace

A gas furnace draws surprisingly little electricity, typically 300–600 W for the blower, plus a brief surge at start. The obstacle is not capacity but connection: a hardwired furnace cannot simply be plugged into a battery, so it needs a transfer switch or an interlock.

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Battery Backup vs Generator

A home battery starts instantly, runs silently indoors, needs no fuel, and stops when its 10–15 kWh are gone. A generator runs for days on refuelling but takes 10–30 seconds to start, must sit outdoors 20 ft from the house, and needs maintenance and stored fuel.

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Backup Power for a CPAP and Medical Devices

A CPAP without heated humidification draws roughly 30–60 W and runs all night on a modest power station. Switch the humidifier and heated hose on and consumption can triple, so size for the configuration you actually use and confirm the device tolerates a modified sine wave.

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How to Compare Power Station Brands

Compare power stations on usable watt-hours, continuous and surge output in watts, and cell chemistry: LFP for 3,000+ cycles and long standby storage, NMC for lighter weight and 500–800 cycles. Model lineups change yearly; those specifications do not.

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EcoFlow vs Jackery: Which Power Station Brand Fits Your Use?

EcoFlow wins on charging speed, output tech and whole-home ambition; Jackery wins on simplicity, weight and a longer consumer track record. The right answer depends on whether you want a power tool or an appliance: EcoFlow's DELTA line recharges faster and scales to circuit-level backup, while Jackery's Explorer line does the core job with less to configure.

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Portable Power Stations Explained

A portable power station is a battery, an inverter and outlets in one enclosure: silent, safe indoors, no fuel or exhaust. Its limit is a single number: usable watt-hours. Continuous and surge wattage decide what it can run; watt-hours decide for how long.

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What Size Power Station Do You Need for Home Backup?

Size a backup power station from your load list: about 1 kWh of usable capacity runs a refrigerator for six hours, a furnace blower wants 2 kWh plus real surge headroom, and backing up circuits rather than devices takes a 240V-capable unit in the 4 kWh class. Multi-day outages need solar recharging or a generator.

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Power Station vs UPS: Which Do You Need?

A UPS exists to prevent an interruption: it switches in milliseconds to keep a computer or network alive through a brief cut, with minutes of runtime. A power station exists to outlast one, with hours of capacity but a slower switchover unless it offers true UPS-mode pass-through.

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Charging a Power Station with Solar Panels

Solar input is what turns a finite power station into something that survives a multi-day outage. Expect roughly 70–80% of the panels’ rated wattage in practice, and match the array to the unit’s MPPT voltage window: too few panels in series and the controller never starts.

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Whole-Home Battery Backup

A whole-home battery transfers in milliseconds, runs silently and needs no attention, but is limited by its stored energy: commonly 13.5 kWh usable per unit. Unless solar can recharge it during the outage, that is roughly a day of essential loads rather than indefinite backup.

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Can a Power Station Run a Refrigerator?

Yes, if the surge rating clears the compressor start. Runtime is better than you'd think, because a fridge only runs about a third of the time.

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How to Size a Portable Power Station

Buy for the load that must run, the surge that must start it, and the hours it must last. Miss any one and the station disappoints.

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LiFePO4 vs NMC Batteries for Backup Power

NMC is lighter and denser. LFP lasts several times longer and is harder to make misbehave. For something that sits in your basement for a decade, that's the trade.

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