Maine homeowners know the drill. A nor'easter rolls through, the lights flicker, and suddenly you're scrambling for flashlights and wondering how long the food in the fridge will last. Power outages are a fact of life across Portland, Scarborough, and the rest of Southern Maine — and they're not getting shorter. Ice storms, high winds, and an aging grid mean some neighborhoods lose power for days at a time.
The question isn't whether you need backup power. It's which type of generator makes sense for your home, your budget, and your lifestyle. At Goodnow Electric, we install both whole-house standby generators and transfer switches for portable units, so we can give you a straight comparison without pushing you toward the more expensive option.
What Is a Whole-House Standby Generator?
A whole-house (or standby) generator is a permanently installed unit that sits outside your home, connected directly to your electrical panel through an automatic transfer switch. It runs on natural gas or propane and turns on by itself within seconds of detecting a power outage — no manual startup, no extension cords, no hauling gasoline.
Standby generators are sized to power your entire home or specific critical circuits, depending on the model and your electrical load. A typical residential unit ranges from 14kW to 26kW, which is enough to run heating, refrigeration, lighting, well pumps, sump pumps, and most major appliances simultaneously.
What Is a Portable Generator?
A portable generator is exactly what it sounds like — a mobile gasoline- or propane-powered unit that you wheel out of the garage, start manually, and connect to your home through extension cords or a manual transfer switch. Portable units typically range from 3,000 to 12,000 watts.
They're a solid emergency backup for keeping the essentials running — a few lights, the refrigerator, phone chargers, and maybe a space heater. But they have real limitations that matter during a multi-day outage in a Maine winter.
Head-to-Head Comparison
Here's how the two options stack up on the factors that matter most to homeowners in Westbrook, Gorham, and surrounding communities:
- Automatic operation — Standby generators start within 10-30 seconds of an outage, even if you're asleep or away from home. Portable generators require someone to be physically present to start them, connect loads, and refuel them every 8-12 hours.
- Power capacity — A standby unit can power your entire home. A portable generator forces you to choose which appliances to run and rotate loads throughout the day.
- Safety — Portable generators produce carbon monoxide and must be operated outdoors, at least 20 feet from windows and doors. Every winter, Maine sees CO poisoning incidents from generators used incorrectly. Standby units are permanently installed outdoors with proper ventilation and pose no indoor CO risk.
- Fuel management — Standby generators connected to a propane tank or natural gas line can run for days or weeks without intervention. Portable generators need gasoline, which means trips to the gas station — assuming gas stations have power.
- Cost — This is where portable generators win. A portable unit plus a properly installed inlet and interlock is a much smaller investment than a standby system. The price of a standby generator installation depends mostly on the generator's size, whether a gas line or propane tank already exists, how far the unit sits from the panel and the fuel source, and whether load management is needed — which is why we quote every install in writing after seeing the house.
- Home value — A permanently installed standby generator increases your home's resale value. A portable generator in your garage does not.
When a Portable Generator Makes Sense
Portable generators are a reasonable choice if your area rarely loses power for more than a few hours, you only need to keep a refrigerator and a few lights running, you have a tight budget and outages are infrequent, or you rent your home and can't install permanent equipment. Even in these cases, we strongly recommend having a licensed electrician install a manual transfer switch so you can safely connect the generator to your panel without backfeeding the grid — a dangerous and illegal practice that puts utility workers at risk.
When a Standby Generator Is the Better Investment
For most Southern Maine homeowners, a standby generator is the smarter long-term choice. This is especially true if you work from home and can't afford to lose internet and power for days, you have a well pump or sump pump that must run continuously, you have medical equipment that requires uninterrupted power, your home has a smart home system, security cameras, or other connected devices that reset during outages, or you simply want peace of mind during storm season without any manual steps.
We install standby generators from leading manufacturers and handle every aspect of the project — from the concrete pad and gas line coordination to the electrical panel integration and automatic transfer switch. We serve homeowners across Falmouth, Saco, and the rest of Southern Maine, with the permit and inspection included on every install.
Pairing a Generator with Solar
Some homeowners combine standby generators with solar panel systems and battery storage for a layered approach to energy resilience. Solar handles day-to-day energy production, batteries cover short outages, and the generator kicks in for extended grid failures. It's the gold standard for energy independence in Maine. If you're curious about how solar and generators work together, read our post on planning electrical systems for new homes — many of the same principles apply to retrofits.
What Size Generator Do You Need?
Sizing a generator correctly is critical. Too small and it won't carry the load. Too large and you've overspent on capacity you'll never use. We calculate your home's electrical load based on your panel, your must-have circuits, and any future additions like an EV charger or heat pump. Our generator sizing guide is a great starting point, but a professional load assessment is the most reliable way to get it right.
Transfer Switch, Interlock, or Inlet: How the Generator Connects
However the generator is powered, it has to connect to your house in a way that can never send power back out onto the utility lines. There are three common approaches:
- Automatic transfer switch (ATS) — Standard with standby generators. The switch watches utility voltage, starts the generator when it disappears, and moves the house over only after the utility side is disconnected. When power returns, it switches back and lets the generator cool down.
- Interlock kit with a power inlet — The usual choice for a portable generator. An exterior inlet box accepts the generator cord, and a mechanical interlock on the panel makes it physically impossible to have the main breaker and the generator breaker on at the same time. You choose which circuits to run by switching breakers.
- Manual transfer switch — A small sub-panel of pre-selected circuits, each with a utility/generator switch. Simple to use, but limited to the circuits chosen at installation.
What you should never do is "backfeed" a house by plugging a generator into a dryer or range outlet with a double-ended cord. It energizes the utility side of your service, endangers line workers, and can destroy the generator when power comes back.
Natural Gas or Propane?
Standby generators run on natural gas or propane. Natural gas is convenient where a line already reaches the house, because there is no tank to refill. Much of Southern Maine has no gas main, though, and those homes run on propane from an above-ground or buried tank. With propane, the tank size decides how long you can run before a delivery — worth thinking about before a long ice-storm outage, when delivery trucks are busy. A licensed gas or propane technician makes the fuel connection; we handle the electrical side and coordinate the two.
Keeping a Generator Ready
A standby generator is an engine, and it needs routine care: oil and filter changes, a battery check, and an inspection of the transfer switch. Most units run a short automatic exercise cycle on a schedule so problems show up before a storm rather than during one. In Maine, also keep snow cleared from the enclosure's air intake and exhaust, and keep the manufacturer's clearances from windows, doors and vents. Our electrical maintenance service can include a pre-winter check.
Frequently Asked Questions
Can a generator run my heat pump? Yes, if it is sized for it. Heat-pump compressors and well pumps draw a surge when they start, so they are included in the sizing calculation. A soft-start device on the compressor can reduce that surge.
Do I need a permit? Yes. Generator and transfer-switch installations require an electrical permit and inspection, and the fuel connection has its own requirements.
How long can a standby generator run? On natural gas, as long as the gas supply holds. On propane, it depends on the tank size and the load.
Local details for our two busiest markets are on our pages for generator installation in Portland and generator installation in Westbrook.
Ready to Talk Backup Power?
Whether you're leaning toward a whole-house standby or want a transfer switch installed for your portable unit, Goodnow Electric can help. We'll assess your home, walk through the options honestly, and give you a free estimate with no pressure.
Contact us online or call (207) 318-1022 to schedule a consultation. The owner is on every job — you'll always know who's doing the work.