Generac Guardian sizing chart by home size — from the 7.5kW PowerPact to the 22kW Guardian. Find the right model for your square footage, appliances, and AC tonnage.
6 models
Guardian lineup covered
7.5–25 kW
Size range
#1 Selling
Home standby brand in US
Quick Answer
The Generac Guardian 14kW is the right choice for most US homes (1,500–2,500 sq ft) with gas appliances and 2–3 ton central AC. For larger homes or all-electric appliances, choose the 18kW or 22kW. For small homes under 1,200 sq ft with no AC: the 10kW is sufficient.
1The Generac Guardian 14kW is America's best-selling home standby — right for most 1,500–2,500 sq ft homes.
2All-electric homes need 4–6 kW more than equivalent gas-appliance homes due to electric water heater and range loads.
3Central AC tonnage drives standby sizing more than square footage — know your AC size before speccing.
4Generac Guardians include Wi-Fi monitoring (Mobile Link app) — check on your generator from anywhere.
5Annual service ($150–$400) is required to maintain the Generac 5-year warranty.
Generac Generator Sizing Chart — All Models
All Guardian and Protector models run on natural gas or LP. Installed cost includes ATS, electrical work, gas line, pad, and permits.
Generac PowerPact 7.5kW
Small home or apartment, gas appliances only, no central AC
Entry-level — no central AC support
Home Size
Under 1,000 sq ft
Unit MSRP
$1,949
Installed
$5,500–$7,500
0 kW7.5 kW rated output27 kW
Generac Guardian 10kW
Small home with gas appliances and 1.5-ton central AC
Cannot run 2+ ton AC comfortably
Home Size
Under 1,200 sq ft
Unit MSRP
$3,299
Installed
$6,500–$9,000
0 kW10 kW rated output27 kW
Generac Guardian 14kWMost Popular
Medium home, gas appliances, 2–3 ton central AC
America's #1 best-selling home standby
Home Size
1,500–2,500 sq ft
Unit MSRP
$4,499
Installed
$8,000–$11,000
0 kW14 kW rated output27 kW
Generac Guardian 18kW
Larger home, all-electric appliances, 3.5-ton AC
Best value for larger homes
Home Size
2,000–3,000 sq ft
Unit MSRP
$5,499
Installed
$10,000–$13,500
0 kW18 kW rated output27 kW
Generac Guardian 22kW
Large home, all-electric, 4-ton AC, EV charging
Powers virtually any residential load
Home Size
2,500–4,000 sq ft
Unit MSRP
$6,099
Installed
$12,000–$16,000
0 kW22 kW rated output27 kW
Generac Protector 25kW
Very large home, commercial, multiple HVAC systems
Liquid-cooled — commercial grade
Home Size
3,500+ sq ft
Unit MSRP
$8,999
Installed
$14,000–$20,000
0 kW25 kW rated output27 kW
Generac Guardian vs. Protector: Which Series Is Right for You?
Guardian Series — Air-Cooled for Most Homes
Generac makes two main residential/light-commercial standby lines:
Guardian Series (7.5–22 kW): Air-cooled engines. For residential use up to ~4,000 sq ft. Most popular for homes. Lower upfront cost, 100-hour service intervals, 5-year warranty.
Protector Series (25–60 kW): Liquid-cooled engines. For very large homes, light commercial, and critical facilities. Higher cost and complexity, but designed for extended runtime and continuous use. 5-year warranty, 200-hour service intervals.
For the vast majority of homeowners, the Guardian series is the right choice. The Protector is overkill for residential use unless you have an unusually large home or commercial property.
How to Use the Generac Sizing Chart
Step 1: Calculate Your Running Load
The easiest way to confirm a Generac model for your home is to use our generator size calculator to get your total running watts and surge watts. Then match that number to the Generac Guardian model that exceeds it:
Calculator Output
Generac Model
Under 7,000 running watts
Guardian 10kW
7,000–10,500 running watts
Guardian 14kW
10,500–14,400 running watts
Guardian 18kW
14,400–17,600 running watts
Guardian 22kW
Over 17,600 running watts
Protector 25kW+
Generac recommends selecting a model with at least 20% headroom above your calculated load — the same 80% rule used by electricians and our calculator.
Where to Buy a Generac Generator
Authorized Dealers vs. Online Retailers
Generac generators are available through authorized dealers (best for installation and warranty service), Home Depot, and online retailers. For whole-house standby installation, always use an authorized Generac dealer — they handle permits, connect to your gas line, install the ATS, and register the warranty.
Find Generac dealers at generac.com/where-to-buy. Get at least two dealer quotes — installation costs vary 20–40% between dealers in the same market.
Use this chart to identify which Generac Guardian kW model fits your home size and coverage requirements.
Why Generac Leads the Standby Generator Market
Generac holds the largest share of the residential standby generator market, and there are concrete reasons for this dominance. First, Generac pioneered the affordable residential standby category, and consequently built the widest dealer and service network in North America. As a result, most homeowners can find multiple authorized Generac installers locally, which keeps installation pricing competitive. Furthermore, this dense network means faster warranty service and parts availability than competing brands typically offer.
However, market leadership does not automatically make Generac the right choice for every home. For example, homeowners in coastal environments sometimes prefer Kohler for its corrosion-resistant housing; similarly, those prioritizing the quietest possible operation may compare decibel ratings carefully. Therefore, while Generac is an excellent default choice, you should still confirm that a well-reviewed local installer supports your chosen brand. Additionally, the specific model matters more than the brand badge, because an oversized or undersized unit performs poorly regardless of manufacturer.
Finally, consider Generac's smart-home advantage. Specifically, the Mobile Link monitoring system lets you check generator status remotely, which is genuinely useful during travel. Moreover, the load-management accessories allow a smaller Generac unit to serve a larger home by intelligently cycling high-draw circuits. Consequently, Generac often delivers whole-home coverage at a lower price point than competitors requiring a larger generator for the same result.
Free Tool
Confirm Your Generac Size with Our Calculator
Get the exact kW requirement for your home before calling dealers — prevents both undersizing and upselling.
