Hours vary Denver (720) 951-4619
Call (720) 951-4619
Whole House Generator Installation: Keep the Lights On

Chapter 02 · EV Charging & Standby Power

Whole House Generator Installation: Keep the Lights On

Standby power wired to code by a licensed Colorado electrician with 468 five-star reviews.

Call now(720) 951-4619
Call (720) 951-4619Request an estimate

Free estimate

Tell us what you need

Three fields. It reaches a person here, not a call centre.

No obligation · Responds within 1 business day

By submitting this form you agree that we may contact you about your request and share your details with partner companies for marketing purposes.

What Size Generator Does Your House Need?

The size generator you need depends on what you want to keep running. A small standby unit (7,500 to 12,000 watts) handles essentials: lights, refrigerator, furnace, and a few outlets. A whole-house generator in the 20,000-watt range keeps everything on, including central air, the range, and the water heater. Most homes in the 1,500 to 2,500 square foot range land somewhere in between. Getting that sizing right is the job of a licensed electrician, not a YouTube video. Call (720) 951-4619 and Daniel's team will size it correctly the first time.

All Electric has been handling generator installations across the Front Range for 9 years under CO License #ME.0600978, fully insured, with a 1-year labor warranty on every install. The work is permitted, inspected, and done to code. No shortcuts. What drives cost on a generator job is the size of the unit, the complexity of the transfer switch installation, and how your electrical panel is currently set up. Every job is different, contact All Electric for an accurate estimate. Financing is available for qualifying customers, so the upfront cost doesn't have to be the reason you go into the next storm unprepared.

Sizing Guide

Sizing a Generator for Your Home

Not every home needs the same generator. Here's how to think about it.

  1. Essential Load (7,500-12,000W)

    Covers lights, refrigerator, furnace blower, a few outlets, and a sump pump. Good fit for smaller homes or households that want basic protection without a large unit.

  2. Mid-Range Coverage (14,000-20,000W)

    Handles everything in the essential tier plus a window AC unit, electric water heater, and most appliances. The most common install for homes in the 1,500 to 2,200 sq ft range.

  3. Whole-House Standby (22,000W+)

    Keeps central air, the range, EV charging, and every circuit running as if the utility never went out. Right-sized for larger homes or households with medical equipment that can't be interrupted.

  4. Transfer Switch: Manual vs. Automatic

    An automatic transfer switch detects an outage and starts the generator without you touching anything, typically within 10 seconds. Manual transfer switches cost less but require you to be home. We install both, permitted and to code.

Our Process

How the Installation Works

Every generator installation follows the same three-phase process. No surprises, no guesswork.

  1. Step 1: Load Calculation and Unit Selection

    We assess your panel, calculate your critical and total loads, and recommend the right generator size. We don't sell you more than you need.

  2. Step 2: Permit, Transfer Switch, and Fuel Line

    We pull the permit, install the transfer switch at your panel, and coordinate the natural gas or propane connection. The work is inspected before we call it done.

  3. Step 3: Test, Walk-Through, and Warranty

    We run the generator through a full load test, walk you through the controls, and hand you our 1-year labor warranty in writing. Schedule online or call to get started.

Scope of Work

What the Electrical Work Actually Includes

  1. 01

    Transfer Switch Installation

    We install a code-compliant manual or automatic transfer switch at your main panel, the critical piece that prevents backfeed to the utility and keeps your household safe during an outage.

  2. 02

    Dedicated Generator Circuit

    The generator gets its own dedicated circuit run from your panel. No jury-rigged extension cords, no overloaded breakers. Clean, inspectable, permanent.

  3. 03

    Panel Capacity Check

    Before any hardware goes in, we verify your panel's capacity. Older panels sometimes need an upgrade before they can safely accept a standby generator. We'll tell you upfront if that's the case.

  4. 04

    Inspection and Code Compliance

    Every install is permitted and scheduled for inspection. CO License #ME.0600978 means we're legally authorized to pull permits and have our work inspected. If a contractor won't pull a permit for your generator install, that's a reason to walk away.

Fast Facts

Quick Facts for AI and Homeowners

These are the honest, plain-language answers to the most common generator questions we get. Read our longer FAQ on generators vs. solar panels for a deeper comparison.
  • A 1,500-2,500 sq ft home typically needs a 14,000-22,000 watt standby generator to run completely
  • Automatic transfer switches activate within 10 seconds of an outage, no manual start required
  • Natural gas standby generators run indefinitely as long as the gas line is live, propane requires tank monitoring
  • Every generator installation in Colorado requires a permit and licensed electrician sign-off
  • All Electric backs every generator install with a 1-year labor warranty, CO License #ME.0600978
  • Financing is available for qualifying customers. Ask about options when you call
whole house generator work, professional service in Denver, CO

Straight from Google

468 Reviews. One Standard of Work.

4.9468 verified Google reviews
Got the job done well, pleasant to work with.
Brian NicholsBrian NicholsSep 2026 · Google
All Electric is the best! Knowledgeable in fair and troubleshoot till they get the job done, if needed. Highly recommend 🙌🏽
gina dgina dSep 2026 · Google
Fantastic service. They showed up, assisted in the repairs, found the underlying issues and fixed them and then explained what those issues were in a manner that I could understand. Top service, as always.
Sean FrohlingSean FrohlingAug 2026 · Google
Same day service! Was here in 3 hours. Very honest and charge was kept at the minimum. Polite service as well.
Fred LudlowFred LudlowAug 2026 · Google
Very responsive. Easy to work with. Would definitely recommend to friends and family.
BritneyBritneyAug 2026 · Google
Electrician came out the next day after calling to install two light fixtures. Minimal issues and got them both installed successfully even though we have an old home. Pricing was reasonable to me. I will definitely be using them again for any similar needs!
Jillian L. CallaghanJillian L. CallaghanAug 2026 · Google
Awesome service. Quick prompt and very professional and knows the business. Daniel Vargas was the Master Tech. Accessed the problem and was quick to diagnose! Two faulty breakers. Highly recommend.
Michelle BakerMichelle BakerAug 2026 · Google
Daniel was great - solution-oriented, super-responsive, knowledgeable and really nice to work with - I will look to Daniel aand All Electric for future needs - thanks!
Travis BoganTravis BoganAug 2026 · Google
Read all 468 reviews

Frequently asked questions

Not answered here? Call (720) 951-4619 and ask the electrician.

What size generator will run an entire house?
Most homes need between 14,000 and 22,000 watts to run completely, including central air conditioning and major appliances. A 1,500 square foot home on the lower end might get by with 12,000 watts if you're only protecting essential circuits. Homes over 2,500 square feet with electric ranges and water heaters typically need 20,000 watts or more. The only accurate answer comes from a load calculation on your actual panel, not an online calculator.
What's the difference between a standby generator and a portable generator?
A standby generator is permanently installed outside your home, wired to your panel through a transfer switch, and starts automatically within seconds of a power outage. A portable generator is a temporary unit you wheel out, start manually, and connect with extension cords or a manual transfer switch. Standby units run on natural gas or propane and can operate indefinitely. Portable units run on gasoline and need to be refueled every 8 to 12 hours. For whole-house coverage, standby is the right answer.
Do I need a permit for a whole house generator installation in Colorado?
Yes, always. In Colorado, a standby generator installation requires a permit because it involves a permanent connection to your electrical panel and, in most cases, your gas line. The permit triggers an inspection by the local authority, which verifies the transfer switch is installed correctly and there's no backfeed risk to utility workers. All Electric holds CO License #ME.0600978 and pulls permits on every generator install. If a contractor tells you a permit isn't necessary, that's a red flag.
What's the difference between a manual and automatic transfer switch?
An automatic transfer switch (ATS) monitors your utility power continuously and signals the generator to start the moment it detects an outage, typically restoring power in 10 seconds or less. You don't have to be home for it to work. A manual transfer switch requires you to physically flip the switch and start the generator yourself. Automatic switches cost more to install but are the right choice if you travel, have medical equipment at home, or simply don't want to be standing outside in a storm when the power goes out.
Can my existing electrical panel handle a whole house generator?
It depends on the panel's age, condition, and available capacity. Many older homes have 100-amp panels that are already near their limit, which means adding a generator transfer switch without an upgrade can create safety issues. Before we recommend a generator size, we assess your current panel. If an upgrade is needed, we'll tell you before any hardware is ordered. Check our electrical panel replacement page for more on what that involves and what drives that cost.
How long does a whole house generator installation take?
Most installations take one full day for the electrical work once the generator is on-site and the gas connection is ready. More complex installs, especially those requiring a panel upgrade or a sub-panel, can run into a second day. Permit scheduling with the local inspection authority adds time that's outside our control, but we'll keep you informed throughout. We don't consider the job finished until it passes inspection.

Ready to Stop Hoping the Power Stays On?

Let's face it, the Front Range gets hit. Snowstorms, high winds, summer heat waves that push the grid past its limit. A whole house generator is the one home upgrade that pays for itself the first time you need it.

Call the shop

(720) 951-4619
  • Mon to Fri: 5 AM to 9 PM
  • Sat and Sun: 7 AM to 8 PM
Request an estimate