Power & Backup
Home Generator Guide
The Short Answer
A home generator keeps the power on during an outage. The two main choices are a permanently installed standby generator that starts automatically and powers your whole home through a transfer switch, or a portable generator that's cheaper but manual and limited. Either way, the connection to your home's electrical system must include a proper transfer switch and be installed by a licensed electrician — never back-fed through an outlet, which is deadly.
When a storm knocks out power, a generator is the difference between a minor inconvenience and spoiled food, a flooded basement, or a freezing house. But the right generator — and a safe connection to your home — takes some planning.
This guide explains the two main types, how sizing works, and why the transfer switch is the most important safety component of any installation.
Standby vs. portable generators — which is right for you?
- Standby generators are permanently installed outside, run on natural gas or propane, and start automatically within seconds of an outage. They can power your whole home and need no manual setup, but cost more up front.
- Portable generators are less expensive and movable, but you start them manually, refuel them with gasoline, and they power only a limited number of circuits. They must connect through a manual transfer switch or interlock — never a regular outlet.
How do I size a generator for my home?
Sizing is about matching the generator's output to the loads you want to run. A small portable unit might cover a refrigerator, a few lights, and a sump pump. A whole-home standby unit is sized to run your essential systems — and often the entire house, including air conditioning — at once.
An electrician calculates your essential loads, accounts for the surge demand of motors like furnace blowers, well pumps, and AC compressors, and recommends a unit that won't be overloaded. Oversizing wastes money; undersizing leaves you in the dark.
What is a transfer switch, and why is it essential?
A transfer switch is the device that safely connects a generator to your home's wiring. It isolates your home from the utility grid while the generator runs, which does two critical things: it prevents the generator from feeding power back onto utility lines (a deadly hazard for line workers), and it protects your equipment when grid power returns.
Automatic transfer switches pair with standby generators and switch over on their own. Manual transfer switches or interlock kits are used with portable generators. In every case, this is a code-required, professionally installed component — plugging a generator into an outlet to 'back-feed' the house is extremely dangerous and illegal.
What does a safe generator installation involve?
- A load assessment to size the generator correctly.
- Proper placement outdoors with safe clearance and exhaust routing.
- Installation of an appropriate transfer switch tied into your panel.
- Fuel connection (natural gas or propane) for standby units, coordinated with a licensed professional.
- Permitting and inspection to confirm the work meets code.
Generator cost ranges
Cost depends on the type and size of generator, the transfer switch, and the complexity of the fuel and electrical connections. These are general planning ranges, not a quote.
Powers a limited set of essential circuits.
Automatic operation, includes transfer switch; varies with size and fuel.
When you already own a generator.
Ranges are for planning only and vary widely by generator size, fuel type, and site conditions. We provide a firm price after an on-site assessment.
Safety considerations
- •Never back-feed a generator through a regular outlet — it can electrocute utility line workers and start fires. A transfer switch is mandatory.
- •Portable generators produce carbon monoxide and must run outdoors, well away from windows, doors, and vents — never in a garage or basement.
- •Undersized generators overload and overheat; oversized ones waste fuel and money.
- •Fuel connections for standby units must be handled by qualified professionals to avoid leaks.
- •Generator installations require permits and inspection to be safe and legal.
When to call a licensed electrician
Not sure where you stand? Try our free electrical capacity assessment or call 484-2-SPARKY.
Have a Question About Your Home?
Tell us what's going on and a licensed electrician will point you in the right direction.
Frequently Asked Questions
Can I just plug a generator into an outlet to power my house?
No. Back-feeding through an outlet is extremely dangerous and illegal — it can send power back onto utility lines and electrocute line workers. A generator must connect through a proper transfer switch.
What size generator do I need?
It depends on which loads you want to run. A portable unit can cover a few essentials, while a whole-home standby is sized to run your essential systems — often including AC — at once. An electrician calculates this for your home.
What's the difference between standby and portable generators?
A standby generator is permanently installed, runs on natural gas or propane, and starts automatically. A portable generator is cheaper and movable but manual, fueled by gasoline, and limited to a few circuits.
Do standby generators turn on automatically?
Yes. Paired with an automatic transfer switch, a standby generator detects an outage and starts within seconds, then shuts down when utility power returns — no action needed from you.
Do I need a permit to install a generator?
Yes. Both standby and properly connected portable installations require permits and inspection, plus a transfer switch tied into your panel. A licensed electrician handles this.
Related Services
Service Areas
Our licensed electricians serve the Main Line, Montgomery County, and Lower Bucks County, including:
Thinking about backup power?
From sizing to a safe transfer switch, a licensed electrician makes sure your generator is ready before the next outage.