What size standby generator does a Johnston home need?

Most homes in Johnston run well on an 18 kW to 22 kW air-cooled standby generator. That range comfortably handles essential circuits—including your furnace blower, sump pump, kitchen appliances, and one central AC unit—for a typical ~1,870 sq. ft. home. Newer or larger builds west of NW 100th Street with finished basements and dual-zone cooling often require a 24 kW unit. Rather than guessing based on square footage, we perform an official NEC Article 220 load calculation to determine the exact wattage your home needs.

Do you need a permit for a generator installation in Johnston?

Yes. A permanently wired standby generator in Johnston requires an electrical permit for the transfer switch and panel work, a gas or mechanical permit for the fuel line, and often a building permit for the pad and site plan. Local permit fees in central Iowa typically run $75 to $400 for the electrical portion. We handle the applications and meet the inspector on site, which keeps the inspection sequence from slipping out of order.

Should your Johnston generator run on natural gas or propane?

Natural gas is best for most homes, as MidAmerican Energy covers most of Johnston and provides an endless fuel supply during long outages. Propane makes sense for larger acreages outside natural gas service areas. Before quoting, we check your gas meter capacity to ensure it can feed a generator running at full load.

How long does a whole home generator installation take?

The job itself takes 1 to 2 days, but count on 2 to 4 weeks total to deal with permits and get the equipment delivered. Day one we set the pad, run the gas line, and handle the main wiring. Day two we install the transfer switch, wire everything up, and test the power. If ground is frozen during winter, pad prep can take a bit longer.

What other electrical work does Mr. Electric of Central Iowa handle near Johnston?

Generators are one piece of what we do across Johnston, Grimes, Urbandale, Polk City, and Ankeny. Common requests include: Electrical panel upgrades when a 100-amp service can't carry a generator plus modern loads EV charger installation on a dedicated 240-volt circuit Circuit breaker replacement for breakers tripping under load Hot tub and spa installation with GFCI protection and a code-compliant disconnect Whole home surge protection at the panel, which matters after a storm restores power

How do you schedule a whole home generator installation in Johnston?

Call us or schedule an appointment with our pros at Mr. Electric of Central Iowa, and we'll set a site visit. Our electrician walks the property, checks your panel and meter, measures the run from the pad to the service, and runs the load calculation. You get a written flat-rate quote covering the unit, transfer switch, electrical work, permits, and startup. We serve Altoona , Grimes , and Urbandale , and we'll fold panel or EV charger work into the same visit.

Whole Home Generator Installation in Johnston, IA

Mr. Electric of Central Iowa installs whole home generators in Johnston, keeping your furnace, sump pump, and refrigerator running when MidAmerican Energy lines go down. Storms rolling up the Beaver Creek corridor take out power here most seasons. As your local Johnston electrician, we size the unit to your home's real load, set the pad, wire the automatic transfer switch, and test the changeover under load before we pack up. You get a flat quote before anyone touches a wire.

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What a Whole Home Generator Installation in Johnston Covers

A standby generator installation involves four pieces of work: a load calculation, pad and unit placement, the fuel hookup, and an automatic transfer switch wired into your service panel. Our Des Moines electrician starts by measuring what your house draws. A 1,900 square foot Johnston home with a three-ton condenser, an electric range, and a sump pump usually lands on an 18 kW to 22 kW air-cooled unit. Houses over 3,500 square feet with two condensers often need 24 kW or larger. Guess at this step and you end up with a generator that drops the load every time the AC compressor kicks on.

Placement comes next. The unit sits on a composite or poured pad, generally 18 inches off the wall and at least 5 feet from any openable window, door, or dryer vent, following NFPA 37 and the manufacturer's clearance table. A licensed gas fitter runs and sizes the fuel line for the added demand. Our electricians then mount the transfer switch, land the feeders, bond the grounding electrode conductor, and program the weekly exerciser. Last step is a live test. We open the utility disconnect, watch the unit crank, confirm transfer time, and run your real house on generator power.

Why Homeowners Call Mr. Electric of Central Iowa For Whole Home Generator Installation in Johnston, IA

We’ve been working around Des Moines since 2001, and our electricians average 15 years on the job. Every member of our team is state-licensed and installs everything strictly to current Iowa code.

Proper installation matters—especially the transfer switch. Setting it up correctly keeps power from backfeeding into the grid, which protects utility workers trying to restore electricity during a storm.

How we handle your installation:

Flat-rate pricing: You get an exact quote upfront for the job, so you aren't paying an hourly rate while we run conduit.
Fully stocked trucks: We carry transfer switches, breakers, and fittings right on the van to finish most jobs without running off for parts.
Respect for your house: We send uniformed electricians, lay down floor protection, and label your breaker panel before leaving.
Guaranteed work: Backed by the Neighborly Done Right Promise®. If an issue pops up a month down the road, we come back and fix it.

Frequently Asked Questions About Whole Home Generator Installation in Johnston, IA

Most homes in Johnston run well on an 18 kW to 22 kW air-cooled standby generator. That range comfortably handles essential circuits—including your furnace blower, sump pump, kitchen appliances, and one central AC unit—for a typical ~1,870 sq. ft. home.

Newer or larger builds west of NW 100th Street with finished basements and dual-zone cooling often require a 24 kW unit. Rather than guessing based on square footage, we perform an official NEC Article 220 load calculation to determine the exact wattage your home needs.
Yes. A permanently wired standby generator in Johnston requires an electrical permit for the transfer switch and panel work, a gas or mechanical permit for the fuel line, and often a building permit for the pad and site plan. Local permit fees in central Iowa typically run $75 to $400 for the electrical portion. We handle the applications and meet the inspector on site, which keeps the inspection sequence from slipping out of order.
Natural gas is best for most homes, as MidAmerican Energy covers most of Johnston and provides an endless fuel supply during long outages. Propane makes sense for larger acreages outside natural gas service areas. Before quoting, we check your gas meter capacity to ensure it can feed a generator running at full load.
The job itself takes 1 to 2 days, but count on 2 to 4 weeks total to deal with permits and get the equipment delivered. Day one we set the pad, run the gas line, and handle the main wiring. Day two we install the transfer switch, wire everything up, and test the power. If ground is frozen during winter, pad prep can take a bit longer.
Generators are one piece of what we do across Johnston, Grimes, Urbandale, Polk City, and Ankeny. Common requests include:
- Electrical panel upgrades when a 100-amp service can't carry a generator plus modern loads
- EV charger installation on a dedicated 240-volt circuit
- Circuit breaker replacement for breakers tripping under load
- Hot tub and spa installation with GFCI protection and a code-compliant disconnect
- Whole home surge protection at the panel, which matters after a storm restores power
Call us or schedule an appointment with our pros at Mr. Electric of Central Iowa, and we'll set a site visit. Our electrician walks the property, checks your panel and meter, measures the run from the pad to the service, and runs the load calculation. You get a written flat-rate quote covering the unit, transfer switch, electrical work, permits, and startup. We serve Altoona, Grimes, and Urbandale, and we'll fold panel or EV charger work into the same visit.

Residential & Commercial Services

Residential
Commercial

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First Name*

Last Name*

Email*

Phone Number*

Street Address**

ZIP/Postal Code*

Yes! You can text me service reminders and other messages.

By entering your email address, you agree to receive emails about services, updates or promotions, and you agree to the Terms and Privacy Policy. You may unsubscribe at any time.

Whole Home Generator Installation in Johnston, IA

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What a Whole Home Generator Installation in Johnston Covers

Why Homeowners Call Mr. Electric of Central Iowa For Whole Home Generator Installation in Johnston, IA

Frequently Asked Questions About Whole Home Generator Installation in Johnston, IA

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