Quick answer: nearly every Generac air-cooled home standby generator, from 10kW up through 26kW, shares one enclosure measuring about 48 x 25 x 29 inches (roughly 122 x 64 x 73 cm). The compact PowerPact 7.5kW sits in a smaller 36 x 27 x 25 inch box. The box itself is rarely the problem. The required clearances around it decide whether an install fits your yard.
This page collects Generac generator dimensions for every current residential model, the space Generac asks you to keep clear, and a practical way to plan a pad that passes inspection the first time.
Generac generator dimensions: Guardian air-cooled models
Generac has kept the same enclosure for its air-cooled Guardian line for years. Their support documentation states that Guardian air-cooled standby generators share the same housing, so the spec sheet numbers repeat down the column:
| Model | Dimensions (L x W x H) | Approx. weight |
|---|---|---|
| Guardian 18kW (model 7220) | 48 x 25 x 29 in | 420 lb |
| Guardian 22kW (model 7043) | 48 x 25 x 29 in | 466 lb |
| Guardian 24kW | 48 x 25 x 29 in | slightly over the 22kW |
| Guardian 26kW | 48 x 25 x 29 in | slightly over the 24kW |
That sameness has a practical payoff most buyers miss. If you are replacing an older Guardian unit, the new one drops onto the same pad. If you are upgrading from an 18kW to a 26kW, you do not need a bigger yard, just a bigger gas line. Our Guardian 24kW review covers that trade-off in detail, because the constraint on the larger models is fuel supply, not space.
Weight stays manageable across the line. The 18kW runs about 420 pounds and the 22kW about 466, which installer crews handle with a liftgate truck and a pallet jack rather than a crane. Spec sheets list dimensions as approximate, so measure the actual unit before cutting a pad to a tight tolerance.
PowerPact 7.5kW dimensions: the compact option
The PowerPact is the model for buyers who need only essential circuits covered: fridge, furnace fan, sump pump, lights, the router. It measures about 36 x 27 x 25 inches and weighs roughly 280 pounds, with a galvanneal steel enclosure instead of the Guardian's aluminum. On propane it produces 7.5kW; on natural gas, 6kW. The bundled transfer switch covers 8 circuits at 50 amps.
Space-wise, the PowerPact has one more trick. Generac's testing supports placing it as close as 18 inches to the house, tighter than the standard Guardian clearance. For a narrow side yard or a townhouse utility strip, that difference can be the whole decision. If even this feels like more generator than your outage history justifies, our standby vs portable comparison lays out what the smaller classes give up.
Clearance requirements: the space around the box
The dimensions on the spec sheet are not the space you need. Generac's installation guidance, which follows the NFPA 37 standard, asks for:
- 5 feet between the enclosure and any door, window, or vent opening. Exhaust near an open window pushes carbon monoxide indoors, so this is a safety line, not paperwork.
- 18 inches from walls at the sides, where the specific model's installation manual allows the tested exception. Check your model's manual rather than assuming.
- 3 feet at the front and rear, the sides your installer works from for fuel and electrical connections.
- Open space above: away from roof overhangs and eaves that trap exhaust.
Local codes can and do override all of these. Your permit office and inspector have the final word, and a good installer quotes the setbacks for your municipality before quoting the pad.
Planning the pad for your Generac generator
Add the clearances to the footprint and a Guardian installation lands in a rectangle roughly 8 feet long by 5 feet deep. That is the zone to keep clear, not just the 4-foot box. Planning steps that prevent do-overs:
- Measure the wall run where the unit will sit and mark the swing of nearby doors and the reach of operable windows.
- Locate the gas meter and the line route. A long gas run adds cost fast, which our installation cost breakdown prices out line by line.
- Ask about property-line setbacks. Many jurisdictions add their own, and they vary.
- Check HOA rules on visibility and noise before the quote, not after the slab is poured.
Gravel or concrete both work as a base; the installer will spec the pad with the equipment. If the site checks out, comparing prices on Generac home standby generators takes minutes and gives you a baseline before dealer quotes arrive. And if you are still sizing the load the box has to carry, run your appliance list through the generator size calculator first. A "best" pick in the wrong size class is an expensive mistake.
Does brand change the footprint?
Rarely. Kohler's air-cooled units sit in the same size class as the Guardian line, within a couple of inches per side, so brand choice seldom changes the pad plan. The real brand differences are price, dealer coverage, and warranty terms, which our Kohler 20kW comparison covers honestly. If you are replacing another brand's old standby, measure the existing slab before assuming a new pour: most swaps land on the original pad.
One exception worth knowing: the Guardian air-cooled line tops out at 26kW. Above that, Generac's liquid-cooled Protector series steps up in a physically larger enclosure, and the footprint math starts over.
FAQ
How much space does a Generac whole house generator need?
The Guardian box is 48 x 25 x 29 inches, but with required clearances you should plan a utility zone around 8 by 5 feet. Local code has the final say, so confirm setbacks with your installer or permit office.
Are all Generac Guardian generators the same size?
The air-cooled Guardian models, from roughly 10kW to 26kW, share one enclosure. The PowerPact 7.5kW is smaller, and the liquid-cooled Protector series is larger.
How close can a Generac generator be to the house?
The baseline rule is 5 feet from any door, window, or vent. Generac's installation manuals allow a tested exception down to 18 inches from walls on specific models, and the PowerPact is rated for 18 inches from the home. Your inspector approves the final placement.
Will a Generac 22kW fit where my old generator sat?
Almost certainly, if the old unit was a Guardian air-cooled model, because the enclosure has not changed. Measure the old slab anyway and compare against the current spec sheet before reusing it.
Bottom line
Generac generator dimensions are refreshingly boring, and that is the good news: one box covers the entire Guardian air-cooled range, one smaller box covers the PowerPact, and neither has changed in years. Measure the clearances before you measure the box, confirm setbacks with the permit office, and the pad plan practically writes itself.
