What is “fluff”?

When we say “fluff,” we mean any extra soft items you put into your child’s car seat or directly onto your child in order to make your child warmer, cleaner, more comfortable, etc. We’re referring to any of the following items which did not come in the box with the car seat:

Fluff on the child’s body

  • Winter coats
  • Snowsuits
  • Swaddles

Fluff added to the car seat that did NOT come with the car seat originally:

  • Sleeping Bag type inserts – where there is a layer of the product that goes under the child’s body and behind the child’s back
  • Head & body supports for infants
  • Padded covers for the shoulder straps
  • Fashion covers (that go over or replace the original fabric cover on the car seat)

But my car seat came with “fluff”! Are you saying that I can’t use it?

Many car seats, especially those for infants, come with extra “fluff,” often in the form of removable inserts for the body and head. You may be wondering why the “fluff” that comes with the car seat is safe to use, but “fluff” that is sold separately is not.

Here’s the answer: Anything in the original box with the car seat (or sold separately AND specifically allowed by the car seat manufacturer) has rigorous standards it must meet; most importantly, it has been crash tested with that particular car seat AND proven to be safe. You’ll probably be surprised by the total number of crash tests required to ensure that a car seat is safe for every size of child allowed in that specific seat.  For example, if a manufacturer creates a car seat for children 4-35 pounds and includes a “fluff” that can be used at any time, with any size child, the manufacturer must crash test that “fluff” with not only 3 separate crash test dummies (the newborn, 12-month-old, and 3-year-old dummies) but also run a separate crash test with each of these dummies in all the various permutations allowed for the shoulder strap and crotch buckle positions. What you may have thought required just one crash test can require literally dozens.

In The Car Seat Lady’s discussions with many of the car seat manufacturers, the engineers have shared with us that they often have to adjust the “fluff” that comes with their own car seats during these crash tests! When they crash test the car seat with the fluff, they don’t always get the results they want; sometimes the fluff actually worsens the car seat’s performance in a crash. The engineers must then redesign the “fluff” so that it does not negatively affect the car seat’s performance. Sometimes they must change the density of the foam or filler used in the “fluff.” Other times the change is as minute as where the stitching line is… and yes, all this can make a difference in how the seat performs in a crash.

“Fluff” sold separately from the car seat does not have to meet any standards or undergo any crash testing. While the manufacturers of some of these aftermarket products may crash test their products, they are certainly not crash testing their products in every car seat on the market, and certainly not crash testing it with all the dummy sizes required and all the shoulder and crotch strap position permutations. Therefore, there is no way to know how these products will affect the car seat’s performance in a crash. For this reason the car seat manufacturers nearly universally forbid the use of extra fluff in their car seats. The exception to the above is that a few car seat manufacturers sell separate “fluff” add-ons for their seats that they have crash tested with their respective seats.

Wait a second, how exactly does “fluff” affect a car seat’s performance in a crash?

Fluff changes the way a car seat fits a child. Fluff may make the straps too loose and may allow the straps to rest on the wrong parts of the child’s body. Both of these changes can lead to performance problems in a crash.

1. Fluff Makes the Straps Too Loose

Crash forces are extreme; they crumple the steel frame of the car! In a crash, not only the steel is compressed, so too are the clothes your child wears and the extra fluff you may have put in the car seat. Fluff can fool you, as it will make the straps seem snug (often super-snug) on your child, but in the instant of a crash when the fluff gets compressed, the straps will be loose (often super-loose) leaving your child at risk in the moment it most matters. Fluff is not your friend when it stands between you and a harness that your life depends on.

Try this experiment to see what we’re talking about — how fluff changes the way the car seat straps fit your child:

  1. Buckle your child in the car seat WITH the fluff (maybe their coat or snowsuit, or the aftermarket sleeping bag insert, etc.) Get the straps snug on the child as if you were going for a car ride. Watch this video, which shows how to remove the slack that often hides in the legs & stomach region (that most parents never even knew was hiding).
  2. Unbuckle the child, but do not loosen the straps. Remove the child from the seat.
  3. Remove all the fluff (i.e. take off the child’s coat/snowsuit, remove the sleeping bag insert, newborn head/body insert you bought separately, etc).
  4. Put your child back in the car seat and see how much extra room there is in the harness; check by pulling firmly upwards on the child’s shoulder straps and seeing if more than a finger fits under the straps at the child’s collar bone.

However loose the straps feel now is exactly how the straps would feel in a crash WITH the fluff (remember, the crash forces compress the fluff to the point that it basically doesn’t exist). If you have room for more than a finger at your child’s collar bone, then the fluff is not safe to use in the car seat because it is preventing the straps from being snug to the child’s actual body.

Now you might be wondering….why does it matter if the straps are a little loose?

The forces that your child’s body feels in a 30mph crash are akin to jumping out a 3rd story window and landing on the pavement. Jumping would be crazy, but if you had to, a parachute would give you the slowest, gentlest stop. If your child’s straps are snug to their body AND the car seat is installed tightly to the car, the car seat will act like a parachute, giving the child the slowest, gentlest stop possible in a crash. If, however, the child’s straps are loose to the body and/or the car seat is installed loosely, the child will come to a jolting stop in a crash, like if you were to jump and land on your feet. This jolt is what causes injury. The jolting also allows the child to move farther forward within the vehicle, increasing the risk of the child hitting their head on hard vehicle structures like the window, door, or the back of the front seat.

When jumping out of a plane, people instinctively understand that their life depends on that parachute harness.  They wear a thin jumpsuit under the harness, not puffy coats, because they want the harness as snug to their body as possible. Do you think anyone ever says “I think my harness is too snug, let’s loosen it up” before they jump out of a plane???  So too, your child’s car seat is a harness that their life depends on. Make sure their straps are properly snug on every ride.

2. Fluff Changes the Way the Straps Sit on Your Child’s Body

Fluff, even when it has openings for the straps to pass through, can cause another potentially deadly problem: displacement of the shoulder straps. In a frontal crash, a rear-facing child will slide up the back of the car seat towards the front of the car. Tightly adjusted shoulder straps hold the child in the car seat, preventing ejection.

The straps on a car seat are spaced precisely to accommodate and restrain small children in this situation. The straps are a specific distance apart, a specific width, and at a specific level all to make sure your child stays in their car seat during a crash. Anything that disrupts or interferes with the way the straps lay on the child will affect the straps’ performance in a crash. For example, if the “fluff” has openings for the shoulder straps that are wider than the strap slots on the car seat, the straps may be too wide to hold the baby where he needs to be in the moment it most counts. Babies have very flexible shoulders, which evolutionarily is a good thing as vaginal deliveries are not possible without them. Car seat engineers, however, have had to work very hard to make sure that these flexible shoulders don’t allow babies to slide right out of their car seats in a crash as the forces pull the rear-facing child’s body up the seat.

Did you know that the problems with fluff extend beyond crashes?

1. Fluff Affects your Child’s Body Temperature

It’s a cold day, you’ve been in the car for about 10 minutes, the heat has finally kicked in and the car is nice and warm… what do you do? You take off your coat! But the child who is dressed for winter UNDER the car seat straps is stuck and forced to overheat as the car is now 70 degrees.

Besides being uncomfortable, overheating can be dangerous for babies and young children because they sweat ineffectively compared to older kids and adults, and are also more vulnerable to the effects of dehydration.  A baby or young child who is overheated may have some of the following signs: constant sweating (damp hair or dampness around the neck/collar area), presence of a heat rash or excess redness in the face, rapid heart rate and breathing, and restlessness (that can then progress to lethargy).

For comfort AND safety it is important to dress kids in a way that they can best regulate their body temperature as they go from the cold outside, to a cold car, to a warm car within several minutes, back to the cold outside, etc.

2. Fluff Affects your Child’s Happiness (and therefore your happiness!)

Properly snug straps already limit a child’s movement in ways they may dislike (which you may hear about every time you buckle your child into the car!) Add to that a winter coat that forces the child’s arms into snowman position — stuck straight out to the sides — and you’ve got a recipe for an angry child.