People searching for Generac generator decibels are usually pricing a home standby generator and wondering what the neighbors will hear. Generac answers that more fully than most makers. Every current air-cooled home standby sheet gives two figures at the same distance, from the same side of the machine, so the whole range lines up. This page lists every current US model with a published figure, explains what each figure means, and ranks them only where the conditions match.
All figures come from Generac's US product pages and spec sheets, read on October 4, 2026. How Generac compares with Kohler, Briggs & Stratton and others is a separate question, and our guide to the quietest home standby generators covers it.
Our picks are listed above, with full specifications for each.
Each air-cooled Generac spec sheet has two sound rows. The first reads "Sound output in dB(A) at 23 ft (7 m) with generator operating at normal load". The second reads "Sound output in dB(A) at 23 ft (7 m) with generator in Quiet-Test™ low-speed exercise mode". Both carry a footnote: "Sound levels are taken from the front of the generator. Sound levels taken from other sides of the generator may be higher depending on installation parameters."
So every figure is sound pressure, A-weighted, at 7 meters from the front. The normal-load figure is what you hear during an outage. The exercise figure is the short weekly or fortnightly self-test that keeps the engine ready, and it is the noise your neighbors hear most often, on ordinary afternoons, whether or not the power ever fails.
We never rank one kind of figure against the other. The gap is wide: the 10 kW model 7257 lists 49 dB(A) in exercise and 61 at normal load, 12 dB(A) apart. Roughly every 10 dB sounds about twice as loud, so that is more than a doubling. Our decibel chart sets these levels beside everyday sounds.
Every air-cooled Generac in exercise mode
Generac sells two air-cooled lines side by side: the newer models with the Power Zone 200 controller, and the Guardian series with the Evolution controller. Each also comes in versions bundled with a transfer switch, which share the generator and its figures. All in Quiet-Test low-speed exercise, at 23 ft (7 m), from the front. Quietest first:
- 49 dB(A): 10 kW model 7257 (7321 with a transfer switch).
- 55 dB(A): the newer 14 kW (7258), 18 kW (7259), 20 kW three-phase (7271), 22 kW (7260), 24 kW (72610), 26 kW (7327) and 28 kW (7282) models, and the Guardian 14 kW (7223, 7224, 7225) and 18 kW (7226, 7228).
- 57 dB(A): Guardian 10 kW (7171, 7172), 22 kW (7042, 7043), 24 kW (7209, 7210) and 26 kW (7290, 7291).
- 58 dB(A): Guardian 20 kW three-phase (7077).
The EcoGen 15 kW (7163) has no exercise figure on its sheet.
Every air-cooled Generac at normal load
The same models, at normal load, at 23 ft (7 m), from the front. Quietest first:
- 61 dB(A): 10 kW model 7257 and Guardian 10 kW (7171).
- 65 dB(A): 14 kW (7258) and 18 kW (7259), and the Guardian 14 kW (7223) and 18 kW (7226).
- 66 dB(A): EcoGen 15 kW (7163).
- 67 dB(A): every model of 20 kW and up, newer or Guardian: 7271, 7260, 72610, 7327, 7282, 7077, 7042, 7209 and 7290.
Here the pattern is simple. Generac's running figure rises with engine size, from 61 at 10 kW to 67 from 20 kW up, and stops there. The 28 kW model is no louder on paper than the 20 kW. If your loads fit an 18 kW unit, that 2 dB(A) is the only noise saving at normal load the range offers, short of dropping to 10 kW.
The two lines overlap at most sizes, and the sheets show exactly where the newer one is quieter. At 10 kW, the newer 7257 lists 49 dB(A) in exercise against 57 for the Guardian 7171, an 8 dB(A) gap for $120. At 22, 24 and 26 kW, the newer models list 55 against the Guardian's 57, and the newer 20 kW three-phase model lists 55 against 58 for the Guardian 7077. At 14 and 18 kW both lines list 55. At normal load, every pair matches.
So the newer range buys a quieter weekly test, not a quieter outage. It also changes how the test is run. The newer sheets say the generator exercises "for 5 minutes every week" by default, with "a selectable setting for weekly, bi-weekly, or monthly operation with an adjustable run time from 5 to 20 minutes, and an option for a low speed engine rpm". The Guardian 10 to 18 kW sheet describes "running the generator for 5 minutes every other week", with weekly or monthly as options. The newer sheet describes low speed as an option, and the exercise figure is for Quiet-Test low-speed mode, so ask your installer to make sure it is selected.
The newer controller adds Smart Exercise, which Generac says "Allows the system to skip its scheduled exercise if the generator ran for more than 5 consecutive minutes within the 72 hours prior to a scheduled exercise event". After an outage, that is one test the neighbors do not hear.
Generac's own quiet features, in its words
Generac's Guardian product pages say "Quiet-Test™ Self-Test Mode runs at a lower RPM for a five or twelve minute test, making generators significantly quieter than other brands while consuming less fuel." The first half is what the exercise figures measure. The comparison with other brands is Generac's claim, and we do not test it here; methods differ between makers, and our explainer on comparing decibel ratings across brands explains why a gap of a few decibels between brands can mean nothing.
The Guardian sheets also describe "Sound attenuated enclosures" that "ensure quiet operation", and a "Quiet, critical grade muffler" mounted inside the unit. Those features sit in every air-cooled model, which is why the figures fall in such a narrow band.
The liquid-cooled Protector series
Generac's residential listing also includes the larger Protector models, with liquid-cooled engines, most of which run at 1,800 rpm when delivering power. Their sheets use different rows: "Sound Level at Exercise Speed" and "Sound Level at Operating Speed & No Load", both at 23 ft (7 m). The XG sheets and the 130 and 150 kW sheet add a footnote that the figure is the "Lowest sound level measurement of 8 locations around the generator." That is a different position and a different load from the air-cooled sheets, so these models get their own lists.
Lowest of 8 points, exercise speed then no load:
- XG 25 kW and 30 kW: 51 and 59 dB(A).
- XG 48 kW: 54 and 58.
- XG 60 kW and 80 kW: 55 and 64.
- XG 32 kW and 40 kW: 59 and 66.
- RG 130 kW: 68 and 72. RG 150 kW: 71 and 77.
Sheets that give no measuring position:
- RG 25 kW and 30 kW at 3,600 rpm: 59 in exercise, and 72 and 73 at no load.
- Protector QS 22 kW and 27 kW: 61 and 70.
- RG 100 kW: 71 at no load, with no exercise figure.
- Diesel 15 to 50 kW: one figure for all five sizes, 65 dB(A) in exercise mode and 70 at normal load. A separate 30 kW diesel sheet gives 65 at exercise speed and 67 at no load.
The XG 25 kW exercises at 1,200 rpm, against 1,800 when running, and Generac lists "Quiet Operation including Selectable Low-Speed Exercise Quiet-Test™" among its features. It also costs $17,199 MSRP and weighs 1,062 lb, so for most homes it is not a quiet alternative to an air-cooled unit but a different class of machine.
Generac's current portable lineup includes the GP2500i and GP3300i inverters, the iQ3500, iQ3800 and iQ5200 inverters, the open-frame GP models from 3,600 to 18,000 watts, and the XD5000E diesel. We read the product page, spec sheet and owner's manual linked for each. None gives a dB figure.
What Generac does say is qualitative. The GP2500i sheet calls it "Quiet and Neighbor Friendly" and says its "fully enclosed design dramatically reduces noise levels." The GP3300i sheet says "Quiet Inverter Power reduces sound emissions and provides optimal performance," and that "Economy Mode automatically adjusts engine speed to save fuel and reduce sound emissions." The iQ3800 sheet says "Quiet Operation - Fully enclosed case reduces noise levels" and "Economy Mode - Reduces noise and fuel consumption."
Those are reasonable descriptions of how inverters work, but without a number, a distance and a load we cannot rank one against another. If quiet is the point, our guide to portable generators for home backup covers models whose makers do publish figures, and our guide to quiet camping generators covers the small inverters.
What the neighbors hear
A home standby generator sits beside the house for decades, so placement matters as much as the figure. Generac's sheets say the units can go "as close as 18 in (457 mm) to a structure" but "Must be located away from doors, windows, and fresh air intakes and in accordance with local codes." Since the figures are taken from the front, point the front away from the nearest neighbor if your installer can.
Local noise rules are measured at the property line, not at 7 meters, and they vary by town. Check yours before choosing a spot for the pad. Our yard noise overview covers the other outdoor machines that add to what a neighbor hears.
How we chose
We read Generac's US product pages and spec sheets for every home standby generator on its residential listing, and the pages, spec sheets and owner's manuals for its current portables. We recorded every sound figure verbatim with its distance, mode, load and measuring position, then ranked exercise figures only against exercise figures and running figures only against running figures taken the same way. The 50 Hz export models on the listing are left out. Picks reflect those figures, output, weight and Generac's own MSRP, which excludes installation.
We did not measure any of these generators. Every figure on this page is Generac's own, quoted from its US spec sheets and product pages as read on October 4, 2026, with the distance, mode and measuring position Generac gives.
