A Generac generator installation is a small construction project: a site has to be chosen, a gas line run, a transfer switch wired in, permits pulled and the whole system inspected and tested. The generator itself is the easy part. Where it goes and what it connects to decide whether the job is quick or complicated.
Most homeowners only do this once. That makes it hard to judge a quote, to know which questions to ask, or to tell a careful installer from a careless one.
This guide walks through the whole process in order. You will learn where a Generac home standby generator is allowed to sit, how much gas each size needs, what the transfer switch does, who handles the permits and what should happen on start-up day. Clearance and fuel figures come from Generac’s own support articles and product pages. We are not installers, and we have not installed or tested these generators.
Generac installation at a glance
Site, gas, switch, permit, test
Clearances are from Generac’s support article and installation manuals. Local codes take precedence.
Quick answer
A Generac home standby generator is installed outdoors on a level base. Generac’s guidance calls for 5 feet from any door, operable window, vent or other opening, 3 feet of clear space at the front and ends, 5 feet above, and 18 inches behind the unit on models that carry the Southwest Research Institute mark. A licensed electrician fits the automatic transfer switch and a licensed gas fitter runs and sizes the fuel line. The job needs permits and an inspection. Local codes always take precedence over the general figures.
How we put this guide together
We are not licensed installers and we have not installed or tested Generac generators. Clearance figures come from Generac’s support article on installation clearances and from its installation manuals. Fuel figures come from the specification tables on Generac’s product pages. Dealer information comes from Generac’s dealer pages. All were checked in October 2026. This guide helps you plan and ask good questions. It does not replace the installation manual for your model, your local codes or a licensed professional.
In this guide
- What Gets Installed?
- Step 1: Size the Generator Before You Pick a Spot
- Step 2: Choose the Location
- Step 3: Plan the Fuel Supply
- Step 4: Choose the Transfer Switch
- Step 5: Permits, Utilities and Paperwork
- Step 6: Installation Day, Step by Step
- Who Does What?
- Can You Install a Generac Yourself?
- After the Installation
- Equipment for a Generac Installation
- Common Generac Installation Mistakes (and the Fix)
- Pro Tips for a Smooth Installation
- Real-Life Scenarios: What Would the Installer Do?
- Generac Generator Installation: FAQ
- Your Generac Installation Checklist
What Gets Installed?
A Generac home standby system has four parts. An installation connects all of them.
- The generator. An engine and alternator in a weatherproof enclosure, sitting outdoors like a central air conditioner. Generac’s air-cooled home models run from 10 to 28 kW.
- The automatic transfer switch. A box near your main electrical panel. It senses an outage, tells the generator to start, and moves your house from utility power to generator power.
- The fuel supply. A pipe from your natural gas meter or your propane tank to the generator, with the right regulator.
- The control wiring and battery. Low-voltage wires let the switch and the generator talk. A 12-volt battery starts the engine.
Generac’s FAQ sums up the result: the generator works whether you are home or away, starts within seconds of sensing an outage, and shuts itself off after utility power returns.
Step 1: Size the Generator Before You Pick a Spot
The size decides the fuel demand, the weight and often the price of the gas work. So sizing comes first.
Generac’s own guidance is simple. Smaller homes may need 10 to 18 kW. Larger homes with more than one air conditioner may need 22 to 28 kW. It says an authorized dealer can best determine the size, through a load assessment at your home.
A load assessment looks at your biggest appliances: air conditioners, heat pumps, electric ranges, dryers, water heaters, well pumps and EV chargers. It also looks at which ones might start at the same moment.
Our Generator Size Calculator gives you a starting figure, and our guide to Generac standby generators compares every size.
Step 2: Choose the Location
This is the decision that shapes everything else. A good spot keeps exhaust away from the house, keeps the gas and electrical runs short, and leaves room to service the machine.
Generac’s clearance figures
Generac’s support article and installation manuals give these general clearances for its air-cooled home standby generators.
| From | Clearance | Why |
|---|---|---|
| Doors, operable windows, vents, window wells and other openings in walls | 5 feet | So exhaust cannot be drawn into the house |
| The back of the generator to a wall, on models with the SwRI mark | 18 inches | Fire testing showed this distance is safe for those models |
| The back of the generator to a wall, on models without the SwRI mark | 5 feet from combustible walls, 3 feet from non-combustible walls | The default fire code distance |
| The front and both ends | 3 feet | For airflow and service access |
| Above the generator | 5 feet | No decks, overhangs or branches close above |
| Shrubs, bushes and trees | The same as the wall clearance | Plants burn, and they block airflow |
SwRI stands for Southwest Research Institute, an independent laboratory. Generac had its enclosures fire-tested there. Models that carry the SwRI mark may be placed 18 inches from a wall. That is closer than the general 5 feet required by NFPA 37, the fire code for stationary engines, which allows a shorter distance for equipment that has been tested.
Generac’s article adds a plain statement: local codes will take precedence. Your town may require more distance from a wall, a property line or a gas meter. The inspector’s reading of the local code is the one that counts.
Carbon monoxide is the reason for the 5-foot rule
Generator exhaust contains carbon monoxide, which you cannot see or smell. Generac’s manuals warn that even a generator placed according to the code may still let exhaust into a building in some conditions, and that it may need to go farther away. Never place a generator under a deck, in a carport, in a breezeway or near an air intake. Fit carbon monoxide alarms on every level of your home, as your local code requires.
Other things a good site needs
- Firm, level ground that drains. The base must stay level and must not sit in standing water.
- A place above flood and snow levels. Drifting snow can block the air intake.
- A short path to the gas meter and the electrical panel. Every extra foot of pipe and wire adds cost.
- Room for the doors and lid to open. A technician needs to reach the engine.
- Distance from bedrooms and neighbors. Generac’s FAQ says its home standby generators average 65 to 67 decibels, similar to a central air conditioner.
- Compliance with property line setbacks and any homeowner association rules.
Key insight: the cheapest location is next to the gas meter and the electrical panel. The correct location is wherever the clearances, the code and the exhaust path allow. When the two differ, the correct location wins.
Step 3: Plan the Fuel Supply
A Generac home standby generator runs on natural gas or liquid propane. Generac’s FAQ says each unit is designed to run on one fuel source, and the choice is set at installation.
How much gas each size needs
A generator burns far more gas than a furnace. The gas line has to be sized for the generator’s full-load demand.
| Size | Natural gas at full load | Natural gas at half load | Propane at half load | Weight |
|---|---|---|---|---|
| 10 kW | 132 cubic feet per hour | 98 | 0.94 gallons per hour | 334 lb |
| 14 kW | 243 cubic feet per hour | 189 | 1.76 gallons per hour | 391 lb |
| 18 kW | 235 cubic feet per hour | 164 | 1.65 gallons per hour | 426 lb |
| 22 kW | 311 cubic feet per hour | 221 | 2.45 gallons per hour | 451 lb |
| 24 kW | 291 cubic feet per hour | 197 | 2.45 gallons per hour | 461 lb |
| 26 kW | 316 cubic feet per hour | 182 | 2.05 gallons per hour | 524 lb |
| 28 kW | 297 cubic feet per hour | 182 | 2.23 gallons per hour | 524 lb |
A cubic foot of natural gas holds about 1,000 Btu. So a 22 kW generator at full load needs roughly 311,000 Btu per hour. A typical gas furnace needs a fraction of that.
Natural gas: meter, pressure and pipe
Three things have to be right.
- The meter. Your gas meter has a maximum flow. If the generator plus your other gas appliances exceed it, the gas utility has to fit a larger meter. Generac lists meter upgrades as one of the things that affect installation cost.
- The pressure. Generac’s product pages list a required natural gas pressure of 3.5 to 7 inches of water column at the generator.
- The pipe. Its diameter depends on the flow and the length of the run. A long run needs a bigger pipe. A gas fitter sizes it from standard tables.
An undersized gas supply is one of the most common installation faults. The generator starts and runs with a light load, then stumbles or shuts down when the air conditioner comes on.
Propane: tank, regulators and pressure
Generac lists a required propane pressure of 10 to 12 inches of water column. A propane installation needs a tank large enough to feed the generator, regulators matched to its demand and a properly sized line.
Tank size matters for two reasons. The first is run time. A 22 kW unit at half load uses about 2.45 gallons an hour, or nearly 60 gallons a day. A 500-gallon tank filled to the usual 80% holds about 400 gallons, which is about a week. The second is vaporization. A generator needs propane as vapor, and a small tank cannot boil off vapor fast enough in cold weather.
Generac’s troubleshooting guidance makes a related point: when the propane level drops below about 30%, fuel pressure can be affected and the generator may fail to start. Keep the tank well above that before storm season.
Our guides to natural gas home generators and propane powered generators cover each fuel in depth.
Step 4: Choose the Transfer Switch
The automatic transfer switch decides which parts of your home get generator power. There are two main approaches.
| Approach | How it works | Best for | Trade-off |
|---|---|---|---|
| Whole-house switch | Installed at the service entrance. Every circuit can use generator power | Homes that want normal life in an outage | Large loads may need managing so the generator is not overloaded |
| Selected-circuit switch | Moves a set of chosen circuits to the generator | Smaller generators and essential loads | Circuits not chosen stay dark |
Generac sells its home generators with or without a switch, and it lists both whole-house switches and 16-circuit switches. It also makes a device it calls the Generac Load Manager, formerly the Smart Management Module, which holds back large appliances so they do not all start together.
A service-entrance rated switch contains the main disconnect and is approved to be the first device after the meter. Whether you need one depends on where your main breaker is.
Our guide on how to connect a generator to your house explains the options in plain English.
Step 5: Permits, Utilities and Paperwork
A standby generator installation almost always needs permits. The details vary by town, but the usual list is:
- An electrical permit for the transfer switch and wiring.
- A gas or plumbing permit for the fuel line.
- Sometimes a building or zoning permit for the placement of the unit.
- Approval from a homeowner association, if you have one.
- A request to the gas utility if a larger meter is needed.
- Notice to the electric utility, where required, because the meter may need to be pulled for a service-entrance switch.
A full-service dealer normally handles the permits and schedules the inspections. Ask about this before you sign. Generac’s dealer pages note that not every dealer offers installation. Its entry-level Select dealers are authorized to sell, but may not install or service.
Our guide to Generac dealers explains the dealer tiers and what each one can do.
Step 6: Installation Day, Step by Step
Every job is different, but the order of work is usually the same.
- Prepare the base. The crew levels the site and sets the base the manual and local code require, such as compacted gravel or a concrete pad.
- Set the generator. These units weigh from about 330 to 525 pounds, so they are moved with a cart, a lift or several people.
- Run the gas line. The gas fitter runs pipe from the meter or tank, fits the shutoff valve and regulator, and tests the line for leaks.
- Mount the transfer switch. The electrician installs it at the main panel or the service entrance.
- Pull the power and control wires. Conduit carries the power cables and the low-voltage control wires between the switch and the generator.
- Make the electrical connections. For a service-entrance switch, the utility power to the house is shut off for part of the day.
- Install the battery. Generac’s current air-cooled models call for an AGM battery of a specific group size, which is usually not included with the generator.
- Set the fuel type. The generator must be configured for natural gas or propane to match what is connected.
- Start and test. The installer starts the generator, checks voltage, frequency and gas pressure under load, and simulates an outage to prove the transfer.
- Set the exercise schedule and remote monitoring. The generator is set to test itself regularly, and Generac’s Mobile Link monitoring is connected.
- Pass inspection. The local inspector checks the electrical and gas work.
- Walk through it with the installer. You should be shown the controls, the shutoff valve, the breaker and the maintenance schedule.
What good start-up testing looks like
A proper test is more than hearing the engine run. The installer should measure the gas pressure with the generator under load, not only at rest. They should switch off utility power and let you watch the house transfer. And they should run your largest loads, such as the air conditioner, on generator power.
Two faults that Generac’s own support articles link to installation are worth knowing by name. A wiring error code can mean the sensing wires to the transfer switch were connected wrongly. A low battery code on a brand-new installation can mean the battery charger circuit is missing its neutral wire. Both are for the installer to correct.
Tip: ask for the test results in writing
Ask the installer to note the gas pressure at rest and under load, the output voltage and the date of the transfer test on your paperwork. If a problem appears later, those numbers show whether the installation was right on day one.
Who Does What?
| Task | Who does the work | Your part as the homeowner |
|---|---|---|
| Choosing the size | Dealer or installer, by load assessment | Decide, with their advice |
| Choosing the location | Installer proposes a spot that meets code | Approve it before work starts |
| Permits | Usually the dealer applies | Sign where needed and keep copies |
| Base and placement | Installer | Clear the area |
| Transfer switch and wiring | Licensed electrician. The utility may disconnect service | Plan for some hours without power |
| Gas line and regulator | Licensed gas fitter. The gas utility upgrades the meter | Request the meter upgrade early |
| Start-up and testing | Installer, electrician and gas fitter | Watch the transfer test and ask questions |
| Inspection | Local inspector | Be available on the day |
| Warranty registration | You or the dealer | Confirm it has been done |
Can You Install a Generac Yourself?
You can buy a Generac generator from a retailer and have it delivered to your driveway. Installing it is another matter.
The work involves your home’s main electrical service and a gas line carrying a large volume of fuel. In most places the law requires licensed trades and permits for both. A mistake on the electrical side can send power back into the utility lines, where it can kill a line worker. A mistake on the gas side can cause a leak or a fire.
What a capable homeowner can reasonably do is the preparation: choose the site with the installer, clear and level the area, have a pad poured, and arrange the propane tank or the gas meter upgrade. Agree on this with your installer in advance, and let licensed people do the connections.
Buying the equipment yourself and hiring an installer is possible, but ask first. Some dealers will only install what they sell, and warranty service is simpler when the installer is an authorized Generac service dealer.
After the Installation
- Register the generator. Generac has a product registration site. Registration ties the warranty to you and makes service easier.
- Set up monitoring. Generac’s Mobile Link can send status alerts by text, email or app notification. Some features need a subscription.
- Learn the lights. A green light means ready. Yellow means a warning or maintenance is due. Red means an alarm.
- Keep the area clear. Hold the clearances for the life of the generator. Do not let shrubs grow in or stack firewood against it.
- Service it. Generac’s maintenance kits are built around a service every 200 hours or two years. In a long outage, Generac says to check the oil level for every 24 hours of use.
- Plan for cold. Generac sells cold weather kits for its air-cooled generators for areas with hard winters.
If something goes wrong later, our guide to Generac generator troubleshooting explains the lights and error codes.
Equipment for a Generac Installation
We have not tested these products. Details come from Generac’s product pages and the Amazon listings.
Most common whole-home size
Generac 22 kW Whole Home Generator with Transfer Switch and Cellular Monitoring
A 22 kW air-cooled standby generator sold with a transfer switch. Generac rates it at 22 kW on propane and 21 kW on natural gas.
- Rating22 kW on LP, 21 kW on NG
- EngineGenerac G-Force 1000
- Natural gas311 cfh at full load, 221 at half
- Propane at half load2.45 gallons per hour
- Weight451 lb
- Warranty on listing5-year limited
- Why it works: generator and switch arrive together, with built-in cellular for Mobile Link monitoring.
- Who it is best for: family homes with one or two air conditioners.
- What it solves: matching a switch to a generator. The package is designed as a pair.
- Keep in mind: it needs a gas supply of about 311,000 Btu per hour at full load. Have the meter and pipe checked. Monitoring needs a Mobile Link subscription, and stock was limited when we looked.
As an Amazon Associate we earn from qualifying purchases. Specs come from Generac’s product pages and the Amazon listing, checked October 2026.
Service-entrance switch
Generac 200-Amp Next Gen Automatic Transfer Switch, Service-Entrance Rated, with Surge Protection
A 200-amp automatic transfer switch that replaces the main disconnect. The listing describes a built-in surge protection device and an aluminum NEMA 3R enclosure for indoor or outdoor mounting.
- Rating200 amps
- TypeService-entrance rated
- Voltage120/240 V, single phase
- Surge protectionBuilt in
- EnclosureNEMA 3R aluminum
- Works withCompatible Generac standby generators
- Why it works: the whole 200-amp panel can be transferred, and the main disconnect is inside the switch.
- Who it is best for: homes where the switch has to be the first device after the meter.
- What it solves: fitting a separate disconnect and surge protector.
- Keep in mind: this is for a licensed electrician to install, usually with the utility’s involvement. Confirm that it matches your generator model before you order.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
Cold climates
Generac 7103 Cold Kit for 9 to 22 kW Air-Cooled Standby Generators
A genuine Generac cold weather kit. The listing says it suits 9 to 22 kW air-cooled standby generators made in 2013 or later, and recommends it where temperatures can fall below 20°F.
- Part number7103
- Fits9 to 22 kW air-cooled, 2013 or later
- RecommendedBelow 20°F
- BrandGenerac
- UseCold weather starting
- Stock on listingIn stock when checked
- Why it works: cold oil and a cold battery are the two things that stop an engine starting in winter.
- Who it is best for: owners in regions with hard winters.
- What it solves: a generator that fails to start on the coldest night of the year.
- Keep in mind: check the model year and size of your generator against the listing. Newer models may use a different kit, so confirm the part number with a dealer.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
Required safety item
Kidde Carbon Monoxide Alarm with 10-Year Sealed Battery and Digital Display
A battery-powered carbon monoxide alarm with a digital display. Generac’s manuals tell owners to use carbon monoxide alarms with any generator installation.
- Power10-year sealed lithium battery
- DisplayDigital, updates every 15 seconds
- Alarm85 dB
- SensorElectrochemical
- MemoryPeak level
- BrandKidde
- Why it works: it needs no wiring and keeps working through a power failure.
- Who it is best for: every home with a generator.
- What it solves: exhaust reaching living space without anyone noticing.
- Keep in mind: an alarm is a backup to correct placement, not a substitute for it. If it sounds, get everyone outside and call for help.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
Common Generac Installation Mistakes (and the Fix)
Pro Tips for a Smooth Installation
- Get three quotes and make sure each covers the same work: permits, pad, gas, electrical, battery, start-up and inspection.
- Ask which dealer tier the installer holds and whether they do warranty service.
- Ask where the gas regulator and shutoff will go. You should be able to reach the shutoff easily.
- Walk the site with the installer and agree on the exact spot before any work starts.
- Order early. Demand jumps after every big storm.
- Keep the manuals and the permit record together. The next owner of your home will want them.
- Check the recall and notification page on Generac’s website for your model when you register it.
Real-Life Scenarios: What Would the Installer Do?
These are typical situations. They are examples to help you plan, not reports from real jobs.
🏡 The narrow side yard
The only space is a five-foot strip between the house and the fence, under a bedroom window.
The window rules that spot out. The installer looks at the back corner instead, and accepts a longer gas run.
Outcome: move it, pay for more pipe
⛽ The small gas meter
The house has a standard meter, a gas furnace, a gas range and now a 22 kW generator.
The installer asks the gas utility for a larger meter before the job is scheduled.
Outcome: meter upgrade first
🛢️ The propane home
There is no natural gas service. The owner has a small tank for the kitchen range.
The propane supplier sizes a much larger tank for the generator and sets it at the required distance.
Outcome: new tank and regulators
Generac Generator Installation: FAQ
How far does a Generac generator have to be from the house?
Generac's guidance calls for 5 feet from doors, operable windows, vents and other openings. Models with the Southwest Research Institute mark may sit 18 inches from a wall at the back. Models without it need 5 feet from combustible walls and 3 feet from non-combustible ones. Local codes take precedence.
Can I install a Generac generator myself?
You can prepare the site, but the electrical and gas connections should be done by licensed professionals with permits. The work involves your main electrical service and a large gas line, and most places require licensed trades for both.
Do I need a permit to install a standby generator?
In most places, yes. Expect an electrical permit and a gas or plumbing permit, and sometimes a building or zoning permit. A full-service dealer usually applies for them and arranges the inspections.
Does a Generac generator need a concrete pad?
It needs a firm, level base that drains. Depending on the model, the manual and your local code, that may be compacted gravel or a concrete pad. Ask your installer what your town requires.
What size gas line does a Generac generator need?
It depends on the generator's fuel demand and the length of the run. A 22 kW unit needs about 311 cubic feet of natural gas an hour at full load. A gas fitter sizes the pipe from standard tables and checks that your meter can supply it.
How long does a Generac installation take?
The physical work is often completed in a day or two. Permits, a gas meter upgrade or a propane tank delivery usually take longer than the installation itself, so the full project can run to several weeks.
Your Generac Installation Checklist
- Have a load assessment done and agree on the size.
- Walk the site and confirm the clearances for your model.
- Check local setback rules and any homeowner association rules.
- Ask the gas utility about meter capacity, or the propane supplier about tank size.
- Decide between a whole-house and a selected-circuit transfer switch.
- Get quotes that include permits, pad, gas, electrical, battery and start-up.
- Confirm who applies for permits and books inspections.
- Watch the start-up test, including a real transfer.
- Ask for gas pressure readings under load, in writing.
- Register the generator and set up monitoring.
- Fit carbon monoxide alarms on every level of the home.
- Keep the clearances free for the life of the generator.
The bottom line
A Generac installation goes well when the location respects the clearances, the gas supply matches the generator’s full demand and licensed people make the connections. Plan those three things first and the rest follows.
As an Amazon Associate we earn from qualifying purchases.
Sources: Generac’s support article on standby generator installation clearances and its installation manuals; NFPA 37 clearance requirements as described there; Generac’s home standby pages, FAQ, dealer pages and product specification tables (generac.com); Generac support articles on error codes; Amazon listings for the products named in this guide. All checked October 2026.
