The sports utility vehicle, commonly known as the SUV, was a big phenomenon in the US during the 1980s and 1990s that then started to spread around the world.
From huge, ungainly monster vehicles they evolved into what we now call the “crossover,” which is consistently the best-selling car type in the world today.
This article answers the question “Are SUVs Quieter Or Louder Than Sedans?”…
Are SUVs Quieter Or Louder Than Sedans?
From the outside, SUVs are still not as quiet as sedans, chiefly because of the typical tire size rolling on the road being louder than that of a sedan, but on a full-size sedan and a smaller crossover SUV, it is very close to the point of being negligible.
On the inside, however, the SUV generally experiences more wind noise than the sedan, but besides that is usually just as quiet, sometimes quieter, as the leading sedans in all NVH metrics – Noise, Vibration, and Harshness.
What Is The Quietest SUV On The Market?
Strictly speaking, the quietest SUV on the market is bound to be one of the electric SUVs that are currently on sale such as the Tesla Model X or the Audi e-Tron.
Let’s take as read that electric is very quiet, but let’s look at non-electric vehicles only.
Most ratings place the Kia Telluride as the quietest and most peaceful SUV you can buy anywhere.
When cruising at 70mph, the noise level inside the Kia Telluride is at a very low 63 decibel sound level, which is a whole 6 decibels better than the Hyundai Palisade.
What Is The Quietest Sedan On The Market?
Currently, the quietest Sedan on the market is known to be the Audi A8, which enjoys the lowest NVH levels among other sedans competing with it on the same score of quietness.
Close rivals to the Audi A8 include the Mercedes-Benz S550e, the Kia Optima, the Cadillac CT6, and the Tesla Model S.
Even with 4.0L engines, the A8 can manage 62.4dB at 74mph, and only 65.1 when traveling almost 90mph.
You might automatically think that an engine with more cylinders would automatically be louder, but this isn’t always the case.
There are examples of inline-4 car engines being louder than a V6 because the overall horsepower of the 4-cylinder engine is greater than that of the V6.
Not all SUVs have V6 and V8 engines either, which is part of why many SUVs, especially compact and crossover SUVs can achieve great low levels of cabin noise compared to sedan cars.
For example, the Mazda CX-9, the GMC Terrain, the Mitsubishi Outlander and the Volvo XC60 are all examples of SUVs that have 4-cylinder engines in 2021.
Equally, many sedan cars come with larger engines, but can still be quieter too.
The Audi A8, the quietest full-size sedan on the market, manages a very pleasing 62.4 decibels even with engines as large as 4.0L and some of them even V8 engines.
Therefore, engine size isn’t directly correlated with engine noise.
The more relevant thing is horsepower. In general, a higher horsepower engine will produce more noise.
Driving a sedan with lower ground clearance offers many benefits compared to an SUV with a higher clearance. First of all, the handling is far better, especially when driving at speeds.
The benefits don’t hold when it comes to cabin noise, however.
As it happens, the lower ground clearance vehicles experience greater cabin noise because they are closer to the road and it’s harder to dampen the noise.
In this way, a crossover or SUV has some advantage when it comes to noise.
SUVs are not only further from the road, but they can install more damping technology to reduce the sound of the road noise.
This is important for them because they often have larger tires which are naturally making more noise as they roll in the road.
When you look at the quietest sedans and the quietest SUVs, you realize that there doesn’t appear to be any real correlation between cabin size and relative engine noise.
The Audi A8 has a large and spacious cabin, for example, at almost 130 cubic feet.
And yet it’s very close competitors for quietest sedans like the Kia Optima have just 120 cubic feet and the Cadillac CT6 just 110 cubic feet.
Such a drop in cabin size doesn’t make the car dramatically more or less quiet. These models all still come very close to the Audi A8 overall.
Windshield & Windows
As most people probably already know, glass is an excellent material to use for soundproofing, and the same is true in sedans and SUVs.
Both sedans and SUVs can benefit from replacing their stock glass with the most effective sound-canceling glass.
The thickness of the glass isn’t the most important element when it comes to canceling noise. The most important quality that the glass can have is being well sealed.
In this respect, there’s no real difference between most SUVs and sedan cars.
Since many brands like Audi, VW, Porsche, Mercedes-Benz and many others offer both sedan and SUV models, it’s safe to assume that they install their glass in the same way and seal it to the same standard or at least very close regardless of car shape.
That being so, having properly sealed glass windows and a windshield helps a lot with cabin noise, but it’s impossible to really say whether sedans or SUVs have an advantage in this area.
On the whole, it’s clear that SUVs have a disadvantage when it comes to tire size and noise.
Full-size SUVs ride on wheels at least 18 inches, and very often wheels of 20-22 inches.
These naturally produce more noise than the more typical 17-inch wheels used on most sedan models.
There are some high-performance sedan models that also ride on larger wheels, but they are rarely built for the purposes of being quieter anyway.
Passenger sedans overall have the advantage when it comes to sedans vs. SUVs for tire size and noise.
When it comes to average decibels, the sedan models will usually pull together quieter levels of between 62 and 65 decibels when traveling at high speeds of 70+mph.
Having said that, you can also get great results from crossover SUVs which are smaller in size and closer to sedans, thus reclaiming ground on the advantages unique to sedans while retaining advantages of the SUVs like somewhat higher ground clearance.
The best-performing SUVs will only manage 63-64 decibels while traveling at speeds of 70+mph, which is not as good as the best-performing sedans.
Taking all SUVs (including crossovers) and all sedans (including mid-size and large) and comparing broadly reveals, however, that the averages are almost on top of each other in being close together.
Wind & Vehicle Shape
Sedan cars are built to direct airflow to the back of the car more quickly and violently.
If you’ve ever noticed why sedan cars do not have a wiper on the rear window where sedans and most hatchbacks do, it has everything to do with vehicle shape.
Sedan cars channel airflow up and over the car to create more turbulence at the rear of the car.
This is enough to keep the window free of contaminants and thus there is no need for the additional wiper there.
The less aerodynamic shape of an SUV, in general, makes more wind noise than on a sedan car, so that adds to the overall noise levels of SUVs and will generally keep them noisier than a sedan.
This is especially the case for the boxier-shaped SUV like the Mercedes-Benz G Class.