Vacuum Insulation vs. Foam: How to Keep Your Drink Hot (or Cold) for All 18 Holes
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Key takeaway Vacuum insulation beats foam because a vacuum has almost nothing in it to carry heat, so it shuts down conduction and convection, the two main ways heat moves through foam. The Thermos® 18oz Icon™ Tumbler with Slide Lock Lid uses double-wall vacuum insulation to keep drinks cold for up to 20 hours and hot for up to 5 hours, long enough to cover a full round of golf. |
All eyes in golf are on the Chicago suburbs this week, as Medinah Country Club hosts the 2026 Presidents Cup from September 24–27. The 16th edition of the biennial match-play event pits Brandt Snedeker’s U.S. Team against Geoff Ogilvy’s International Team on a reimagined Course No. 3. It’s classic fall golf in the Midwest: crisp early mornings, afternoons that warm up fast and long days outside.
That’s exactly the kind of day that exposes a bad cup. Whether you’re teeing it up at your home course, hosting a Presidents Cup watch party or heading out on a fall road trip, what stands between a hot first-tee coffee and a lukewarm one on the back nine is insulation. Here’s how the two main types compare, and how to get every hour out of yours.
What’s the difference between vacuum insulation and foam insulation?
Heat moves in three ways: conduction (through solid material), convection (through moving air or liquid) and radiation (as infrared energy). Any insulated tumbler is trying to slow all three.
Foam insulation fills the gap between an inner and outer wall with foam. The foam traps tiny pockets of gas, which slows heat transfer, but the foam and the gas inside it still conduct heat. Foam slows the flow; it doesn’t stop it.
Vacuum insulation takes the opposite approach: the air is removed from the space between two stainless steel walls. With almost no molecules left in that gap, there’s very little to carry heat by conduction or convection. That’s why a thin vacuum-sealed wall can outperform a much thicker layer of foam, and why Thermos® has built its drinkware around vacuum technology for more than a century.
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Vacuum insulation |
Foam insulation |
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How it works |
Air removed between two steel walls |
Foam fills the gap between walls |
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Conduction |
Virtually eliminated |
Reduced |
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Convection |
Virtually eliminated |
Reduced |
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Wall thickness needed |
Thin |
Thicker for similar results |
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Temperature retention |
Generally longer |
Generally shorter at the same size |
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Best for |
All-day hot and cold drinks |
Short trips and casual use |
Why vacuum insulation matters on the golf course
A round of golf is a stress test for any drink. You’re outside for hours, your cup rides in a cart or sits in the sun between shots, and the temperature can swing 20 degrees between your tee time and your last putt. Vacuum insulation handles all of it:
• Hot for up to 5 hours carries a morning coffee or tea from the first tee through the back nine.
• Cold for up to 20 hours covers a dawn tee time, the 19th hole and the drive home.
• Sweat-proof, condensation-free exterior means no wet grip, no damp glove and no rings on your scorecard.
Featured pick: Thermos® 18oz Icon™ Tumbler with Slide Lock Lid
The 18oz Icon™ Tumbler with Slide Lock Lid is built for days like this. At $26.99 in 18 colors, from Mystic Navy to Crimson to Alpine Green, it’s an easy pick for your bag, your cart or a golf-loving friend.
• Double-wall vacuum insulation: up to 20 hours cold and 5 hours hot
• Slide lock lid: closes between sips and is straw-compatible when open (cold drinks only)
• Lumiview™ lid: see what’s left at a glance
• Griptec™ base: non-slip, quiet and soft-touch
• Fits most standard cup holders (golf cart holders vary, so check yours)
• 18/8 BPA-free stainless steel, top-rack dishwasher safe
Gifting tip: add custom laser engraving for member-guest prizes, league champions or your Presidents Cup watch-party host.
How to keep your drink hot or cold longer: 6 tips
1. Prime your tumbler. Fill it with hot water (or ice water) for a few minutes, dump it out, then add your drink. The steel starts at the right temperature instead of pulling heat from, or adding heat to, your drink.
2. Fill it close to the top. Less air space means less heat exchange every time you open the lid.
3. Keep the slide lock closed. The lid is the main escape route for heat, so close it between shots.
4. Start with plenty of ice. For cold drinks, a full cup of ice buys you more hours than a splash of cold water.
5. Save straws for cold drinks. The slide lock lid is straw-compatible when open, but use straws with cold liquids only.
6. Clean it right. The tumbler is top-rack dishwasher safe; let the lid dry completely before reassembling.
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Headed to a tournament? Big events such as the Presidents Cup follow the PGA TOUR’s permitted and prohibited items list and screen every guest at the gate. Check the policy before you go. Your tumbler may be best enjoyed on the drive in, at your own tee time or at your watch party. |
Frequently asked questions
Is vacuum insulation better than foam insulation?
Yes, for temperature retention. A vacuum has almost no molecules to carry heat, so it nearly eliminates conduction and convection, while foam only slows them down. Vacuum-insulated drinkware generally keeps drinks hot or cold longer than foam-insulated drinkware of a similar size.
How long does the Thermos 18oz Icon Tumbler keep drinks hot and cold?
The Thermos® 18oz Icon™ Tumbler with Slide Lock Lid keeps drinks cold for up to 20 hours and hot for up to 5 hours.
Will the 18oz Icon Tumbler fit in a golf cart cup holder?
It fits most standard-size cup holders. Golf cart holders vary by model, so check yours if it runs smaller than a typical car cup holder.
Is the Thermos 18oz Icon Tumbler dishwasher safe?
Yes. It is top-rack dishwasher safe.
When and where is the 2026 Presidents Cup?
The 2026 Presidents Cup is being played September 24–27, 2026, at Medinah Country Club in Medinah, Illinois, outside Chicago.
Ready for your next 18? Shop the Thermos® 18oz Icon™ Tumbler with Slide Lock Lid or explore the full Icon™ Series.