What Size Pool Pillow Do I Need

If you’re preparing your pool for winter, you’re probably asking, what size pool pillow do I need? Getting the right size is crucial for protecting your cover and pool from ice damage.

A pool pillow, or ice compensator, sits under your cover. It absorbs pressure from expanding ice and freezing water. This simple device can prevent costly damage to your pool walls and liner. But if you choose the wrong size, it won’t work properly.

This guide will help you find the perfect fit. We’ll cover how to measure, the different types, and installation tips.

The size you need depends primarily on the size of your pool cover. It’s not about the pool’s length or width directly. The pillow needs to be large enough to create a raised dome under the center of the cover.

This dome allows rain, snow, and melting ice to run off. It prevents a heavy, sagging pocket of water from forming. That sagging pocket can strain your cover and anchor system.

Here is the standard sizing guideline most pool owners follow:

Small Covers (up to 16′ x 32′): Use a 4′ x 8′ or 4′ x 10′ pool pillow. This is a common size for many rectangular above-ground pools.
Medium Covers (up to 20′ x 40′): A 5′ x 10′ or 5′ x 12′ pillow is often recommended. It provides more lift for larger surfaces.
Large Covers (over 20′ x 40′): Opt for a 6′ x 13′ or 8′ x 16′ pillow. For very large in-ground pools, you might even need two pillows.
Round Pools: Match the pillow length to roughly one-third to one-half of your pool’s diameter. For an 18′ round pool, a 4′ x 8′ or 5′ x 10′ pillow is usually sufficient.

When in doubt, check your pool cover’s manual. Many manufacturers suggest a specific pillow size. You can also call the cover company for there advice.

How to Measure for Your Pool Pillow

Don’t guess your cover size. Taking a few minutes to measure ensures you buy correctly.

Measure the length and width of your pool at its longest and widest points. Include the coping or edge.
Add 2 to 4 feet to each dimension. This accounts for the cover’s overhang, which is needed for securing it. For example, a 16′ x 32′ pool typically uses an 18′ x 36′ or 20′ x 40′ cover.
Use this final cover size (not the pool size) with the sizing chart above.

Special Pool Shapes

Oval, kidney, or freeform pools need a bit more thought. The key is to think about the cover’s central area.

For oval pools, use the cover’s length. Then choose a pillow that spans about half the width of the center.
For kidney or irregular shapes, visualize the largest rectangle that would fit under the center of the cover. Size your pillow for that rectangle. Sometimes, placing two smaller pillows in key areas works better than one large one.

Types of Pool Pillows and Materials

Not all pool pillows are the same. The material affects durability and performance.

Standard Vinyl Pillows

These are the most common and affordable option. They are made from heavy-duty PVC or vinyl. Look for reinforced seams and a quality air valve. They typically last 3-5 seasons with proper care. Avoid cheap, thin vinyl that can puncture easily.

Durable Fabric-Reinforced Pillows

These have a layer of mesh or fabric between two layers of vinyl. This makes them much more resistant to tears and punctures from debris or sharp cover edges. They are a great investment if you want a pillow to last many years.

Disposable Pillows

Made from thinner plastic, these are designed for one season of use. They are a low-cost option if you don’t want to store a pillow over the summer. However, they are less eco-friendly and can fail mid-winter if punctured.

Step-by-Step Installation Guide

Putting in your pool pillow correctly is just as important as choosing the right size.

Partially Inflate: Inflate your pillow to about 60-70% capacity. Use a manual pump or a low-PSI electric pump. Never use a high-pressure air compressor, as it can overinflate and burst the seams. The pillow should be firm but still have some give.
Position in Center: Place the partially inflated pillow in the center of your pool. For rectangular pools, align it lengthwise down the middle. For round pools, center it. It should not be touching the sides of the pool.
Tie It Down: Most pillows have grommets or tie-down straps. Use the supplied ropes or separate pool pillow ties. Secure the pillow to the pool’s anchor points or around the pool itself. The goal is to keep it centered, not to pull it tight. Allow some slack for the pillow to rise and fall with water pressure.
Deploy Your Cover: Carefully lay your winter cover over the pool and the secured pillow. As you secure the cover with water tubes, winches, or springs, the pillow will press up against it, creating the desired dome.
Final Adjustment: Once the cover is secure, you may need to add a little more air to the pillow. The cover should be lifted, but not stretched drum-tight. A gentle slope is what you want.

Common Mistakes to Avoid

A few simple errors can reduce your pillow’s effectiveness.

Over-inflating: This is the number one mistake. An overinflated pillow is more likely to pop when the ice pushes down on it. It can also put too much stress on your cover’s center. Remember, it needs to compress to do its job.
Under-inflating: A soft, underinflated pillow won’t create enough lift. The cover will sag, collect water, and defeat the whole purpose.
Poor Positioning: If the pillow is off-center or touching the wall, it won’t distribute pressure evenly. This can lead to cover damage or a lopsided water collection.
Using the Wrong Ties: Don’t use wire or sharp plastic zip ties. They can cut the pillow or cover. Use soft nylon rope or plastic cord designed for pools.
Forgetting About It: Check the pillow’s air level once or twice during the winter, especially after a big temperature swing. It may need a small boost of air.

Maintenance and Storage Tips

Taking good care of your pool pillow extends its life.

When winter ends, deflate the pillow completely. Open the valve and gently roll it to push all the air and moisture out. Clean it with a mild soap and water solution to remove any algae or dirt. Let it dry thoroughly in the sun before folding.

Store it in a cool, dry place away from direct sunlight and rodents. Avoid folding it in the exact same way every year to prevent creases from weakening. A loose roll is often better than a tight fold.

Before reinstalling each fall, inspect it for cracks, brittleness, or leaks. Inflate it and submerge it in a bathtub or lay it on the grass and listen for hisses. Patch small holes with a vinyl repair kit.

When One Pillow Isn’t Enough

For very large pools, long rectangular pools (over 40 feet), or pools with unusual shapes, a single pillow may not provide enough support.

In these cases, using two smaller pillows is often the best solution. Place them evenly along the length of the pool, like two supports under a bridge. Ensure they are both securely tied and centered. This creates two high points that help the shed water and ice more effectively.

Some pool owners with auto-covers or solid safety covers also use multiple pillows. They help prevent a large span of cover from being submerged under heavy snow load.

FAQ Section

How do I know what size pool pillow to get?

Base the size on your winter cover’s dimensions, not the pool itself. Measure your cover’s length and width, then refer to a standard sizing chart (e.g., 4×8 for covers up to ~16×32, 5×10 for up to ~20×40).

Can a pool pillow be too big?

Yes. An oversized pillow can be difficult to center and may push too aggressively against the cover, causing undue stress. It can also drift and touch the pool walls, which reduces its effectiveness. Stick close to the recommended size for your cover.

What happens if my pool pillow deflates?

If it deflates completely, your cover will lose its central support. A large pocket of water will likely form, putting heavy weight on the cover and its anchors. This can lead to a torn cover, damaged anchors, or even pool wall damage from the ice. Check its air level periodically.

Do I need a pool pillow for an above ground pool?

It is highly recommended. Above-ground pool walls are especially vulnerable to ice pressure. A pillow helps protect the structure of your pool, not just the cover. It’s a critical part of winterizing an above-ground model.

How much air do you put in a pool pillow?

Inflate it until it is firm but still slightly compressible with hand pressure—usually about 60-80% full. It should not be rock-hard. Leave room for it to compress under the weight of ice and snow, which is its main function.

Choosing the correct pool pillow is a simple but vital step in winterizing. By matching the size to your cover, installing it with care, and avoiding common errors, you’ll give your pool the best protection against winter’s freeze. This helps ensure you’ll have a clean, undamaged pool ready for opening when warmer weather returns. Taking the time to get it right now saves you from headaches and expensive repairs in the spring.