Why Don’t Sedans Have Rear Windshield Wipers?

Rear windshield wipers clean the window glass at the back of the vehicle. They wipe away dirt and moisture that might otherwise block the rear view. However, not all vehicles have this device on their rear windshield. Sedans almost always don’t have a rear wiper. In contrast, most hatchbacks have a rear windshield wiper. So why don’t sedans have rear wipers?

Why Don’t Sedans Have Rear Wipers?

Several factors determine the feasibility, practicality, and usefulness of a rear windshield wiper on the rear windshield. These are the common reasons why sedans generally don’t have rear wipers:

Aerodynamics and Airflow

Generally, sedans don’t need rear wipers. Their aerodynamic profile creates airflow that cleans their rear windshield.

The vehicle’s shape determines its aerodynamics, which is how an object moves through the air. Sedans and hatchbacks have dissimilar shapes, so air flows differently over each type.

A sedan has a tapering rear end with a sloped rear windshield and the trunk jutting from under the glass. Its smooth surfaces enable air to flow without interruption from sudden, steep drops. The unimpeded airflow carries water on the windshield away from the surface of the car glass.

Thanks to airflow over its rear end, a sedan doesn’t need a windshield wiper to remove water from its rear windshield. However, heavier things like dirt and snow might remain on the windshield.

Putting a rear windshield wiper on a sedan usually disrupts the car’s aerodynamic silhouette. The airflow might lift the rear wiper, much like how an aircraft’s wings generate lift.

In contrast to the sedan’s sloping rear windshield, the hatchback’s rear window and the door that mounts it are vertical. This sharply upright shape lowers the air pressure in the area behind the hatchback, creating a vacuum effect that pulls in the surrounding air. The ensuing airflow disturbs particulate matter like dirt and dust, which end up on the rear windshield and the rest of the hatchback door.

Furthermore, the swirling air doesn’t flow across the hatchback’s tailgate, preventing it from removing dirt and moisture on the rear windshield. Since airflow can’t do the job, hatchbacks often have a rear windshield wiper that can clean the rear windshield window glass.

Increased Fuel Consumption

Aerodynamics also affects how much fuel the vehicle burns. Much like water, air resists things that move through it. The greater the air resistance, the more energy it requires to overcome it.

Sedans usually have a sleek silhouette that minimizes aerodynamic drag, allowing the car to easily move while burning the minimum amount of fuel. Installing a wiper on the rear windshield disrupts the streamlined profile, creating drag that reduces the vehicle’s speed. The engine must burn more fuel to generate additional power to compensate for the drag.

Trivia: One technical service bulletin on fuel economy published by Ford Motor Company back in the 1980s said a vehicle will experience 40% more wind drag at 65 mph than at 55 mph.

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No Space in the Rear

Windshield wipers are complex devices. They’re made up of multiple parts, such as an electric motor that moves the wiper arm and the wiper blade that scrapes away dirt and water. These parts take up space, and technology can only do so much to reduce their size before they become ineffective.

Unfortunately, the sedan’s rear windshield doesn’t have much room for a windshield wiper. While the front end can fit the front wipers under the car hood, the rear end with the trunk doesn’t have the same arrangement.

In contrast, a hatchback has space for a windshield wiper system. The rear wiper can fit in the vertically oriented rear door. Furthermore, the wiper won’t interfere with the hatchback’s aerodynamic profile. However, these rear wipers are usually small, especially if you compare them to the front wipers.

Cargo Area Layout Interference

Car manufacturers design the vehicle’s cargo area based on factors like vehicle type and body. Unfortunately, the general layout for sedans makes it difficult to fit a wiper on the rear windshield.

When you open the sedan’s trunk, the trunk lid moves up and back toward the windshield. If the rear windshield has a wiper, there’s a chance that the fully opened lid might hit the device. Windshield wipers aren’t the sturdiest things, and they might get damaged if the trunk lid hits them.

Sedan models with factory-issue rear wipers usually impose a limit on how much you can open the trunk lid. However, the safety feature can hinder you when you load, unload, or use the trunk. If you can’t raise the trunk lid past a certain point, you might find it difficult to put something in the trunk or take the cargo out of the storage space.

Hatchbacks use a different layout for their cargo area. The rear wiper is mounted on the tailgate, keeping it clear of anything that can hit it when you open the hatch. You can open the rear door without worrying about the rear windshield wiper.

Also, while SUVs have liftgates, coupes and sedans don’t, and neither do pickup trucks. This makes it very difficult to design a sensible rear wiper system on anything that’s not an SUV.

Unpleasant Aesthetics

Rear windshield wipers don’t look as good as their front-mounted counterparts. People are used to seeing front wipers, so they’ve normalized the mechanisms in their minds.

In comparison, windshield wipers look out of place on the sedan’s rear windshield. It might affect a person’s willingness to acquire the vehicle. If the potential buyer doesn’t think the convenience of having a rear wiper outweighs its unusual appearance, they might not seal the deal.

Installing a Rear Wiper on Your Sedan

If you do want a rear wiper, installation kits are available on the market. However, you might have to modify your sedan to support the new wiper. You should also choose a product that’s compatible with your sedan model.

Rear Windshield Wiper Alternatives

Do you want to keep the rear windshield clean without using a rear wiper? There are several options available.

Regular Cleaning

Make a habit of cleaning the rear windshield. You can prevent dirt from accumulating on the windshield’s surface and reduce the chances of water sticking to the glass.

Hydrophobic Coating

You can also apply a hydrophobic coating on the rear windshield. The coating repels water and might stop dirt from clinging to the glass.

There are a few different products that work well for this. You may want to choose a brand that’s well known and widely used. Just make sure your glass is very clean before applying any product.

Use the Defroster

Does your car have a defroster? You can use that to remove condensation and ice from the rear windshield.