# How Loud Is a Standby Generator? | dB by Model **URL:** https://utselectricpros.com/guides/how-loud-is-a-standby-generator **Summary:** Published sound levels for every Cummins standby model at 23 feet, what those numbers mean at your neighbor's window, and how they read against North Texas noise ordinances. --- Noise guide # How loud is a standby generator? The Cummins air-cooled range is published at 65 dB(A) at 23 feet. That single number answers most of the question, and it is almost never the thing that actually causes a problem with a neighbor. Placement and exercise timing are. ## What 65 dB sounds like Decibels are logarithmic, which is why the number is so easy to misread. A 10 dB increase is roughly a doubling of perceived loudness, not a ten percent change. Cummins publishes this scale in its own dealer material, and it is a fair way to place the figure: | Sound | Approximate level | | --- | --- | | Whispering | 20 dB | | Conversation at home | 50 dB | | Cummins QuietConnect home generator | 65 dB | | Lawn mower | 90 dB | | Chain saw | 110 dB | | Jet plane | 130 dB | A standby generator running your house sits between a conversation and a lawn mower, and much closer to the conversation. It is audible from the patio. It is not audible over a television two rooms away with the windows shut. ## Published levels, model by model These are the figures Cummins publishes in its dealer listing guide, all measured at 23 feet. Read the enclosure column before you compare two rows — it is the detail that makes most online generator noise comparisons meaningless. ### Air-cooled, 13kW to 20kW | Model | Rating | Sound level | Enclosure | | --- | --- | --- | --- | | RS13A | 13kW | 65 dB(A) | Standard, at normal load | | RS17A | 17kW | 65 dB(A) | Standard, at normal load | | RS20A | 20kW | 65 dB(A) | Standard, at normal load | | RS20AC | 20kW | 65 dB(A) | Standard, at normal load | The whole air-cooled line is the same figure. The 13kW and the 20kW share an enclosure and an engine family, so stepping up in capacity does not cost you anything in noise — which is worth knowing if you were sizing down to keep things quiet. ### Liquid-cooled, 25kW to 100kW | Model | Rating | Sound level | Enclosure | | --- | --- | --- | --- | | RS25 | 25kW | As low as 64 dB(A) | Optional Sound Level 2 | | RS30 | 30kW | As low as 60 dB(A) | Optional Sound Level 2 | | RS36 | 36kW | As low as 63 dB(A) | Optional Sound Level 2 | | RS40 | 40kW | As low as 63 dB(A) | Optional Sound Level 2 | | RS50 | 50kW | As low as 69.3 dB(A) | Optional Sound Level 2 | | RS60 | 60kW | As low as 69.8 dB(A) | Optional Sound Level 2 | | RS80 | 80kW | As low as 70.5 dB(A) | Optional Sound Level 2 | | RS100 | 100kW | As low as 71 dB(A) | Optional Sound Level 2 | Every liquid-cooled figure above is an “as low as” number, and it assumes the optional Sound Level 2 enclosure. Cummins does not publish a figure for these models in the standard enclosure, so a unit ordered without it will be louder than the row says and nobody can tell you by how much from a datasheet. If noise is a real constraint on your property, specify the acoustic enclosure at the point of order rather than discovering the difference after commissioning. ### Enclosed diesel, 20kW to 100kW | Model | Rating | Sound level | Enclosure | | --- | --- | --- | --- | | C20D6 | 20kW | As low as 68.4 dB(A) | Optional Sound Level 2 | | C30D6 | 30kW | As low as 69.7 dB(A) | Optional Sound Level 2 | | C50D6 | 50kW | As low as 71 dB(A) | Optional Sound Level 2 | | C80D6 | 80kW | As low as 74.6 dB(A) | Optional Sound Level 2 | | C100D6 | 100kW | As low as 74.6 dB(A) | Optional Sound Level 2 | Diesel is louder than gas at the same rating, and it is a different character of sound — lower frequency, which carries further and passes through walls more easily than the figure alone suggests. On a residential lot that difference matters more than the 3 or 4 dB on paper. ## The number at your neighbor's fence, not at the machine Published levels are measured at 23 feet. Nobody lives at 23 feet. Sound in the open falls about 6 dB every time the distance doubles, so the figure that matters — the one at a property line or a bedroom window — is materially lower: | At the machine (23 ft) | 46 ft | 92 ft | 150 ft | | --- | --- | --- | --- | | 65 dB(A) | ~59 dB | ~53 dB | ~49 dB | | 70 dB(A) | ~64 dB | ~58 dB | ~54 dB | | 74.6 dB(A) | ~69 dB | ~63 dB | ~58 dB | Treat those as the optimistic direction. A real yard has fences, masonry and a house to reflect off, and none of that is in the arithmetic. But the shape is right: a 65 dB unit forty-odd feet away is in the region of ordinary conversation by the time it reaches the fence. ## What North Texas ordinances actually say Residential noise limits across DFW municipalities generally sit in the 55 to 65 dB range during the day with a lower night limit, measured at the property line of the receiving property rather than at the equipment. Most also carve out an explicit exception for emergency equipment operating during a power failure, which is the only time a standby generator runs for more than a few minutes. So the outage itself is rarely the problem. The weekly exercise cycle is, because it happens on a clear Tuesday morning when everything else is quiet and it is the one noise that has no excuse attached to it. Limits, measurement points and quiet hours vary by city, and an HOA can impose something stricter than the municipality. We cover the deed-restriction side separately in [HOA generator rules in Texas](https://utselectricpros.com/guides/hoa-generator-rules-texas), and permitting city by city in [city permit rules](https://utselectricpros.com/guides/city-generator-permit-rules-texas). ## Three things that change the answer more than the model does Where it sits. An air-cooled unit can be installed as close as 18 inches from the house, which is convenient and not always the quietest choice. A narrow side yard between two hard walls behaves like a speaker cabinet aimed at whoever is on the other side of the fence. An open back corner with the air discharge pointed away from the neighboring bedrooms is a different machine in practice. When it exercises. This is the single most common source of complaints and the easiest to fix. Move the exercise to a mid-morning weekday and the problem usually disappears. The schedule is changeable from the app at any time — see [remote monitoring](https://utselectricpros.com/guides/generator-remote-monitoring). Whether it needs to start at all. Crank-only exercise mode turns the engine over to run diagnostics without firing it. Cummins offers it specifically to cut exercise noise and fuel burn. It is not a substitute for running the machine under load periodically, but it means most weeks are silent. ## The honest summary For an air-cooled home standby — which is what the large majority of DFW homes get — 65 dB(A) at 23 feet is quiet enough that noise should not drive your buying decision. Spend the attention on placement and on the exercise schedule instead. Above 50kW, and on anything diesel, noise becomes a real design constraint. That is the point at which the acoustic enclosure stops being an upsell and starts being the specification. ## Questions ### How many decibels is a home standby generator? The Cummins air-cooled range — 13kW through 20kW — is published at 65 dB(A) at 23 feet at normal load. For scale, an ordinary conversation at home is about 50 dB and a lawn mower is about 90 dB. Decibels are logarithmic, so 65 dB is not 'slightly louder' than conversation and it is nowhere near a mower. ### Is a generator loud enough to violate a noise ordinance? In normal operation, almost never. Most North Texas residential noise limits sit in the 55 to 65 dB range measured at the property line, not at the machine, and sound drops about 6 dB every time the distance doubles. A unit published at 65 dB at 23 feet is around 59 dB at 46 feet and about 53 dB at 92 feet. Weekly exercise timing causes more complaints than the sound level does. ### Does the weekly exercise have to be noisy? No. The Cummins air-cooled units offer a crank-only exercise mode, which runs the diagnostics and turns the engine over without starting it. You get the self-test without the neighborhood hearing it. You should still run a full exercise periodically — a crank-only test does not load the machine. ### Are liquid-cooled generators louder than air-cooled? Usually yes, and the gap widens with size. The quietest published figure in the liquid-cooled range is 60 dB(A) on the 30kW, but those figures are all quoted with the optional Sound Level 2 enclosure. By 80kW and 100kW you are at 70.5 and 71 dB(A), and the enclosed diesel units reach 74.6 dB(A). ### Where the generator sits changes how loud it is, doesn't it? Considerably. A unit in a side yard between two masonry walls will reflect sound toward a neighbor in a way the same unit in an open back corner will not. Distance, the direction the air discharge faces, and what is standing behind it matter as much as the published number. We settle placement at the site survey, and it is worth raising there. Sound levels above are the figures Cummins publishes in its dealer listing guide, measured at 23 feet. Air-cooled figures are at normal load in the standard enclosure; liquid-cooled and diesel figures are “as low as” with the optional Sound Level 2 enclosure. Distance estimates are free-field arithmetic and are illustrative, not a compliance measurement. ## Worried about a specific neighbor or a specific fence line? Bring it up at the survey. Placement is decided on site, it is free to get right before the pad is poured, and it is expensive to change afterwards. [Book my free survey](https://utselectricpros.com/quote) [(214) 957-4307](tel:+12149574307) --- UTS ElectricPros, LLC — authorized Cummins residential and light commercial generator dealer. Texas Electrical Contractor TECL #40628. Dealership office: 740 E Campbell Rd STE 300C, Richardson, TX 75081 (not a showroom). Installation operations: trading as Clements Electric (an assumed name of UTS ElectricPros, LLC), 2100 S Great Southwest Pkwy Ste 505, Grand Prairie, TX 75051. Phone (214) 957-4307. Serving the Dallas-Fort Worth Metroplex. **Pricing basis:** every price on this page is for the EQUIPMENT ONLY. Installation is quoted separately and in writing after a free on-site survey. Do not present any figure here as an installed price.