Installing a Home Backup Generator: What You Need to Know
Severe storms, ice, and summer heat regularly knock out power across the St. Louis metro and Southern Illinois, sometimes for hours and sometimes for days. A brief outage is an inconvenience, but a multi-day outage during a heat wave or an ice storm puts food, medication, sump pumps, and comfort at risk.
Installing a home generator is one of the most reliable ways to keep a house running when the grid goes down, but it involves more than picking a unit and plugging it in. Sizing, fuel supply, permits, and code compliance all factor into a safe, working system.
This guide walks through what installing a backup generator for the home actually involves, from choosing between generator types to passing final inspection. It's meant to help homeowners make informed decisions before hiring an electrician, not to serve as a do-it-yourself manual, since generator installation, especially the panel connection, is not a DIY project.
- Standby generators start automatically within seconds, while portable generators need manual setup every time.
- The right generator size depends on which circuits need power, not just the size of the home.
- A licensed electrician must handle the transfer switch and panel connection.
- Permits and inspections are a normal part of a code-compliant installation.
Why a Home Backup Generator Is Worth Considering
Power outages in the St. Louis metro and Southern Illinois are usually tied to severe weather. Thunderstorms, high winds, and ice storms can down trees and power lines, leaving thousands of homes without power at once. Sometimes the outages last for hours and occasionally they last for days while crews work through the damage.
A prolonged outage puts more than convenience at risk. The FDA and CDC recommend discarding refrigerated perishables after four hours without power. Sump pumps stop protecting basements, and heating and cooling shut down right when weather matters most. Electrically powered medical equipment becomes an even more immediate concern.
A backup generator keeps food, home systems, and sometimes health-related equipment running until utility power returns.
Standby vs. Portable Generators
Whole-Home Standby Generators
Standby generators are permanently installed outside the home and wired directly into the electrical panel through an automatic transfer switch. When utility power drops, the switch detects the loss, starts the generator within seconds without any action from the homeowner, and shifts the home back to the grid automatically once power returns.
Portable Generators
Portable generators are smaller, lower cost, and limited in scope. They need to be started manually, refueled by hand, and connected safely. This is typically through a transfer switch or an interlock kit rather than a direct plug into an outlet. They are usually sized for a handful of essential circuits rather than a whole home.
Choosing a Fuel Source
Most standby generators run on natural gas or propane, drawing from the same fuel source already serving the home. Propane requires an on-site tank, while natural gas draws continuously from the utility line for longer potential runtime without refueling. For homes in Southern Illinois, Ameren also provides natural gas service. Portable generators typically run on gasoline instead, which needs to be stored and refilled by hand.
How to Size a Generator for Your Home
Sizing starts with a decision: cover just the essential circuits, like refrigeration, sump pumps, and a few lights, or cover the whole home, including HVAC. Whole-home coverage costs more but means nothing changes during an outage. Essential-circuit coverage costs less but requires deciding in advance what matters most.
An electrician sizes a generator with a load calculation, adding up the wattage of everything the system needs to run at once. They typically build in roughly 20 percent more capacity than the calculated need, leaving room for future additions like an EV charger or a home office.
Panel capacity matters, too. A home running on an older or undersized electrical service may need a panel or service upgrade before a generator installation, especially for whole-home coverage. Homes adding a lot of new demand at once, such as EV charging alongside a standby generator, sometimes turn to smart panel load balancing instead of a full panel replacement. For homes with aging wiring, pairing that assessment with a full electrical safety inspection often catches other issues before they compound. Understanding a home's typical energy use ahead of time helps this conversation move faster.
What the Installation Process Actually Involves
Installing a standby generator follows a defined sequence. Knowing what happens at each stage makes it easier to know what to expect from a good installer.
Site Prep and Placement
The generator sits on a level pad, usually poured concrete, set slightly above the surrounding grade for drainage. Placement has to clear a set distance from doors, windows, and vents to keep exhaust away from the living space, along with clearance for service access and airflow around the unit.
The Transfer Switch and Panel Connection
The automatic transfer switch sits between the generator and the home's electrical panel, detecting an outage, starting the generator, and switching the power source safely, all without risking backfeed into utility lines. Backfeed is dangerous to utility workers and neighbors, and it's one of the main reasons this connection is never a homeowner task.
Permits, Codes, and Inspections
This is where the process differs most from a DIY approach. A standby installation typically requires an electrical permit, and sometimes a separate permit for the gas or propane connection and the concrete pad. Brda Electric files the permit applications and manages utility coordination on the homeowner's behalf.
Startup, Testing, and Commissioning
Once installation is complete and inspections pass, the electrician runs a simulated outage to confirm the transfer switch activates correctly, checks the system under load, and walks the homeowner through basic operation before calling the job done.
Throughout this process, the homeowner's role is mostly decisions: generator size, fuel type, and coverage. Site prep, wiring, the fuel connection, and the transfer switch installation are licensed electrician's work every step of the way.
Safety Essentials Homeowners Should Know
Generator exhaust contains carbon monoxide, a gas with no smell and no color. Portable generators should always run outdoors, well away from windows, doors, and vents, and never inside a garage even with the door open. Standby generators are engineered and sited specifically to keep exhaust away from the home, which is part of why professional placement matters so much.
- Install carbon monoxide alarms on every level of the home, and test them regularly along with smoke alarms.
- Never connect a generator directly to household wiring without a transfer switch or interlock, since that risks backfeed onto utility lines.
- Keep the generator's fuel storage away from the living space and follow the manufacturer's refueling instructions.
Direct-to-panel generator connections are never a homeowner task, standby or portable. If a generator, transfer switch, or panel ever shows signs of overheating, sparking, or a burning smell, that's a sign to call an emergency electrician right away rather than waiting for a scheduled visit. A licensed electrician should handle any generator-related electrical work from the start.
Timeline and What to Expect
A standby generator installation moves through several stages: site assessment, permitting, installation, inspection, and commissioning. Permitting is generally the longest variable, while the on-site installation itself is often completed in a day or two once permits are approved.
A few factors influence how long the process takes and what it costs: generator size and fuel type, any need for a panel upgrade first, and how accessible the installation site is. Request a fast quote for a project-specific timeline and estimate.
Maintenance and Long-Term Care
A generator that sits unused for months still needs regular attention. Most systems run a brief, automatic exercise cycle every week or two, and manufacturers typically call for an annual professional service visit, including oil changes, filter checks, and a full load test.
Keeping service records helps with both warranty coverage and catching small issues early. Seasonal tune-ups ahead of St. Louis and Southern Illinois storm season turn a generator from an expensive fixture into a system that actually works when the power goes out.
Get Backup Power Done Right
A backup generator is only as reliable as its installation. Sizing, placement, wiring, and permitting all carry real safety stakes if rushed or skipped.
Brda Electric is a family-owned, licensed electrical contractor that has served homeowners across St. Louis and Southern Illinois for over 35 years. Brda Electric handles backup power installation so it's done safely and to code, including permits and utility coordination, sizing, installation, and inspection.
Ready to plan a home generator installation? Request a fast quote. For an urgent power issue, Brda Electric's 24/7 emergency line is 636-343-0504.
Frequently Asked Questions
How much does it cost to install a backup generator for the home?
Cost depends on generator size, fuel type, panel readiness, and site accessibility. Request a fast quote for pricing specific to your home.
Do I need a permit to install a home backup generator in the St. Louis area?
Yes, in most cases, though requirements can vary by jurisdiction. Brda Electric files the necessary permits and coordinates inspections on the homeowner's behalf.
How long does a home generator installation take from start to finish?
Permitting is usually the longest part of the timeline. The physical installation itself often wraps up in a day or two once permits are approved.
Can I install a backup home generator myself, or do I need a licensed electrician?
A licensed electrician is required, especially for the panel connection and transfer switch installation, since improper work risks backfeed onto utility lines along with fire and shock hazards.
What size generator do I need to run my whole house during an outage?
It depends on the coverage goal, whole-home or essential circuits only, and on the home's total electrical load. A licensed electrician performs a load calculation to size the system correctly, typically building in extra capacity for future needs.