to top 10 table

Our Favorite Insulated Tumblers for 2019

last updated Apr 12, 2019
Every day there seems to be a new brand on the market boasting the ability to keep your beverages hot or cold for hours upon hours on end. There are differences in the insulation technology and materials used to achieve this can be the difference in the effectiveness and the ability for it to last for a long time in various external temperatures. Ensuring that there are additional helpful features such as spill protection or comfort in your hand are also important. The ability to fit into most cup holders is especially useful because most of us will use our cups in our cars at some point. With all the many products on the market, we assessed our list based on the criteria of accuracy, use, and style. We have included various sizes and specialties to compile a comprehensive list.

In a Hurry? The test winner after 18 hrs of research

icon
Greens Steel BEAST
98/100 our score
Insulation
98
Use
98
Style
98
Greens Steel BEAST
Why is it better?

Total Bundle including 2 unbreakable steel straws, straw brush, 1 splash proof lid packaged with a gift box

Insulation and temperature retention

Premium 304 18/8 Food Grade Stainless Steel

Sweat-free design with nice color options

Long-lasting powder coating to protect against rust or scratches

Electro-polished interior so that you won't get any unwanted flavors

Lifetime guarantee and 100% satisfaction

In a Hurry? Editors choice:
Greens Steel BEAST
Test Winner: Greens Steel BEAST
Researched Sources
4
Researched Sources
Reviews Considered
1.8k
Reviews Considered
Hours Researching
18
Hours Researching
Products Evaluated
16
Products Evaluated
Sorting Options
Insulation Use Style By Default
Rank
PictureProduct
Name
Rating
Shops
#1
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
98
Insulation
98%
Use
98%
Style
98%
Price Comparison Last Updated (21.04.19)
$23.95
#2
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97.7
Insulation
98%
Use
99%
Style
96%
Price Comparison Last Updated (21.04.19)
$15.99
#3
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97.3
Insulation
97%
Use
97%
Style
98%
Price Comparison Last Updated (21.04.19)
$21.95
#4
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97
Insulation
99%
Use
96%
Style
96%
Price Comparison Last Updated (21.04.19)
#5
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.7
Insulation
96%
Use
95%
Style
96%
Price Comparison Last Updated (21.04.19)
$16.95
#6
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.3
Insulation
95%
Use
96%
Style
95%
Price Comparison Last Updated (21.04.19)
$29.09
#7
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95
Insulation
94%
Use
95%
Style
96%
Price Comparison Last Updated (21.04.19)
$24.95
#8
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.3
Insulation
93%
Use
94%
Style
93%
Price Comparison Last Updated (21.04.19)
$16.58
#9
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93
Insulation
90%
Use
94%
Style
95%
Price Comparison Last Updated (21.04.19)
$16.99
#10
The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
90.3
Insulation
90%
Use
89%
Style
92%
Price Comparison Last Updated (21.04.19)
$13.49
In Depth Review Top 10
  • Greens Steel BEAST
  • MalloMe
  • Earth Drinkware
  • YETI Rambler
  • Arctic
  • Tervis
  • Corkcicle
  • RTIC
  • Bottlebottle
  • Obstal
Table of contents
  • Criteria Used for Evaluation
  • Other Factors to Consider
  • Frequently Asked Questions
  • Sources

Our Favorite Insulated Tumblers

1. Greens Steel BEAST

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
98
Greens Steel BEAST
Insulation
98
Use
98
Style
98
best offer for today
$23.95
Pros:

Total Bundle including 2 unbreakable steel straws, straw brush, 1 splash proof lid packaged with a gift box

Insulation and temperature retention

Premium 304 18/8 Food Grade Stainless Steel

Sweat-free design with nice color options

Long-lasting powder coating to protect against rust or scratches

Electro-polished interior so that you won't get any unwanted flavors

Lifetime guarantee and 100% satisfaction

Cons:

Design of top could be improved

Greens Steel Beast is the total package. The stainless steel cup with lid also includes two unbreakable straws which provides you with a great backup should you have any issues losing one. There is also a brush for easy and effective cleaning and you can choose from a variety of stylish color options to suit your personal tastes. Packaged in an appealing gift box so it makes a great present or stocking stuffer for any family member or friend.

Read more

Materials and Finishing

The robust double wall uses vacuum technology with a copper lining that ensures for proper encasement that will keep cold beverages icy and hot beverages steaming. High quality 18/8 food-grade steel keeps you safe and doesn't allow for any aftertaste to seep into your beverage. The coating is non-fading so you can get a longer lifespan out of the fun, bright color options that are available in this line.

Features

The plastic in the lid is solid, as it is unbreakable and shatterproof made of safe, BPA-free Tritan plastic. It will easily slide open and closed for you, ensuring you can close off any potential splashing if you are in uneven terrain or in the car. You get the option of backups with the two straws that are included. These are reusable and also made of high quality 18/8 steel with a wide opening to accommodate both viscous drinks including smoothies, as well as easily flowing drink like coffee or tea. If you opt for a thicker liquid that can cause debris to build up inside the straw, no worries because the included brush will help loosen and scrub clean the inner walls of the straws to keep them clean.

Cost and Value

This package is very well priced and a true value with all the features you get especially when compared to other, much more pricey options that exist on the market. The color options are pretty and a really nice thing is that there is satisfaction and money back guarantee if you aren't happy with your product.

2. MalloMe

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97.7
MalloMe
Insulation
98
Use
99
Style
96
best offer for today
$15.99
Pros:

Included are the embossed logo with 2 style lids (leakproof and sliding), a tumbler handle, stainless steel straw, and straw brush

Packaged in a nice matte box

304 18/8 stainless steel construction inside and out

Rustproof

Narrow & tall design

Lifetime and satisfaction guarantee

Cons:

Handle and lid can be tough to clean

MalloMe makes a cup that can keep up with the busiest of schedules or the most rugged of activities. Made of stainless steel with a convenient clip-on handle for easier gripping and grasp, you get a very versatile beverage holder. 2 lids, a reusable steel straw along with the cleaning brush, rounds out this well put-together package.

Read more

Leak-proof Travel Lids

This product comes with two lids so that you can easily get the best out of each drink you choose. A sliding spout is a great option for those drinks that are hot like coffee, and the rubber plugged spout is perfect for cold drinks like iced water. This allows for ultimate versatility that you can have whether you are in the car or hydrating at the gym.

Convenient

These are tall so that they can hold a good amount but they don't stay stout throughout. Their bottoms are slimmer so that you can fit them into almost any cup holder for convenient mobility. The lids also are designed for easy cleaning in the dishwasher which saves you time and effort. This allows you to switch between lids so that you always have a clean one on hand.

Cost and Value

You are getting tremendous value in this bundle pack. A bunch of pieces that work well together with a ton of versatility in a very favorable price range. It is well designed and nicely packaged as well.

3. Earth Drinkware

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97.3
Earth Drinkware
Insulation
97
Use
97
Style
98
best offer for today
$21.95
Pros:

Available in 20 oz. or 30 oz. sizes

Double-Wall with a vacuum seal to help retain hot and cold temperatures

Leakproof, Flip-Top Lid

Made with stainless-steel and comes with a color-matched lid

Has a reusable drinking straw that is also steel and bent

Backed by a long-lasting reliability, durability, and satisfaction guarantee

Cons:

The straw can hit against the inside and cause a lot of clanking noises

Can be wide for some cup holders

This is a stylish option that comes in a ton of snazzy color options and effects like shimmery rose gold. This product is double-walled and vacuum-sealed. Earth Drinkware makes a beverage holder that offers a good amount of durability given that it is rust and corrosion-resistant.

Read more

Fun Design

The fun color options will suit anyone's personality and while looks are always a nice feature they don't sacrifice functionality. You don't have to worry about condensation coating your hands or cup holders and you can comfortably hold this cup without worrying about your hands getting too cold or hot because of the drinks you are carrying in it. You can get it in a 20 or 30 oz. size and it is super portable.

Bent Straw

The reusable straw is made out of steel as well and has a bent design. It is going to work well for thicker drinks like smoothies as well as those beverages that are less viscous like water. The bent design makes it much easier to drink especially when in the car.

Cost and Value

The color options are really snazzy and this product is well worth the bargain price. It will keep your drinks hot or cold for hours upon hours during the day. The construction is excellent and it is very versatile.

4. YETI Rambler

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
97
YETI Rambler
Insulation
99
Use
96
Style
96
best offer for today
more shops
Pros:

Strong brand recognition and reputation

The standard with the MagSlider Lid

BPA-free, dishwasher safe, and have a No Sweat Design

DuraCoat is a durable coat of color that won't fade, peel, or crack

Double-wall and made with an 18/8 stainless steel body

Stands 6 7/8 in high and has a lip diameter of 3 1/2 in

These are all sized to fit in standard sized cup holders

Cons:

Doesn't have a rubberized grip disc on the bottom

The YETI Rambler is like many of other Yeti products you may have come to know, it fits the company's reputation of making rugged and tough gear. Using 18/8 stainless steel construction, double-wall vacuum insulation, and No Sweat Design, they ’re going to fit any activity or adventure you could want.

Read more

Durable and Practical

You have plenty of pattern and color options to choose from with a robust 12. The DuraCoat will maintain it's color and vibrancy as it can stand up to the elements allowing it to stay attractive without any color fading, chipping, or peeling. They can fit in most any holder for either the 20 or the 30 oz sizes so either way you go, they are very portable.

Strong

This brand is well-known for high-quality products that are very strong and made to be beaten up in the elements. This rambler will keep your beverages at the temperature you desire for countless numbers of hours no matter what conditions they are in. If you are ready to hike out in the blazing sun, all you need to do is fill it up with some cold water and ice and you are set with a cool beverage that won't let you down no matter how blistering the sun may be.

Cost and Value

The cost is higher than others in the market but it's not impractical. The reason this brand is so popular is because of it's a strong reputation for making quality products and you see that in the price. If you want something you can count on in any environment this is a product that won't let you down.

5. Arctic

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.7
Arctic
Insulation
96
Use
95
Style
96
best offer for today
$16.95
Pros:

Can keep drinks hot for up to 6 hours or cold and icy for up to 24 hours with the vacuum technology

The body is made with HYPOALLERGENIC 18/8 grade stainless steel

The lid is made from Tritan plastic and contains No BPA or BPS

Sweat-free construction

Powder coat finish provides a solid grip

100% refund

Cons:

The lid's sealing capability could be improved

The lid can easily come off if dropped accidentally

The Arctic makes a product that you can use for many activities including camping, traveling and day-to-day activities. It comes with a splash-proof lid and a reusable straw. The double-wall vacuum seal keeps temperatures solid over longer periods of time and the matted powder coat comes in a couple of durable color options.

Read more

Built Well

These have a durable powder coat with nice color options and the no-sweat design makes them easier to grip and hold in hand. The double-wall insulation will help keep beverage temperatures desirable. The solid kitchen grade 18/8 stainless steel will protect against corrosion, rust, and degradation.

Features

These can house very hot or icy cold beverages. They are safe to drink from because the material used in construction is BPA-free and the lid is a solid Tritan plastic that also contains no BPA as well as no BPS. These are laser welded with no corners so you can get a good scrub done in them which is specifically helpful if you are drinking a gritty smoothie or shake out of them that can cause debris to stick to the inner walls.

Cost and Value

The price is right for this beverage holder that you can use in any outdoor situation. A nice feature is the awesome customer service that will assist you in any event that you are unhappy with your product. This company wants to ensure you are happy and we can all appreciate that.

6. Tervis

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95.3
Tervis
Insulation
95
Use
96
Style
95
best offer for today
$29.09
Pros:

Co-polyester BPA and Melamine free construction

Microwave, freezer & dishwasher safe

Lifetime Guarantee

Made in the USA

Comes in a pack of 4

Cons:

Glass can become fogged or opaque with hot, steaming beverages

A film can develop when using citrus like lemon juice

Tervis is a family-owned company that is based out of the state of Florida. They have been developing and manufacturing drinkware since 1946. They make a line of various insulated drinkware that is stylish and functional. This product is about 6 inches tall with approximately 3 inches in diameter.

Read more

Solid Company

This family-owned company has been around for over 70 years and they are leading experts in manufacturing insulated cups. This cup will reduce condensation with the double-wall design so they won't soak coasters or cup holders. They are safe with furniture as they won't cause water rings and they are comfortable in your hands.

Safe Materials

The construction uses BPA-free materials that are not just cost-effective but they are safe. They are also convenient and safe to wash in the dishwasher when put on the top rack. They can also hold up if you choose to hand wash and dry, it is really your preference.

Cost and Value

This product comes in a nice bundle pack of 4 so that you should always have a clean cup when you need it. They are dishwasher safe, and the price is right for these many tumblers. This company has been around since 1946 and they pack a solid customer satisfaction reputation with a nice unlimited quality guarantee.

7. Corkcicle

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
95
Corkcicle
Insulation
94
Use
95
Style
96
best offer for today
$24.95
Pros:

Funky color options including Sparkle Pixie Dust and Unicorn Magic

Triple-insulated stainless steel

Non-slip bottom with easy grip sides

Spill-proof lid

Cons:

Colors may look different in person than in the picture

If you love wine, you will love this product. Corkcicle is the only authorized seller of this unique wine cup. Using 18/8 stainless steel it has a canteen design and is stemless. The triple insulation will keep those beloved beverages cold for 9 hours, and if you need a hot toddy, you can keep the heat in for about 3 hours.

Read more

Design

This is stemless and can hold 12 oz. making it the perfect companion for cocktails or wine, and for those who prefer non-alcoholic drinks tea works well too. The patented grip set up makes it easy to hold in the hand and the silicone bottom will keep it from sliding around so you can ensure your beverage is less likely to spill.

Versatile

You can use this for your favorite adult beverages or your morning coffee or tea. It is sturdy on almost all surfaces and won't slip easily. The nice grip will make it super comfortable to hold and the design will ensure that you won't feel the temperature of your beverage on your hand.

Cost and Value

There are really pretty color options in this line but the price is on the higher end. If you like having a cup that can be a pretty go-to for most beverages and has the consistency that it won't likely spill, this is a nice option.

8. RTIC

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93.3
RTIC
Insulation
93
Use
94
Style
93
best offer for today
$16.58
Pros:

Double wall vacuum technology

Can hold ice for up to 24 hours

18/8 stainless steel construction

Narrow and tall design, makes an easy grip, no-sweat exterior

Cons:

The design of the flip top could be improved, it can have difficulty locking in place

Very hot beverages may cause a slight metallic taste

RTIC is made of stainless steel and uses a double wall vacuum system to keep drinks at their ideal temperatures. The lid is shaded to allow you to get a better understanding of how much you have drunk versus how much you have left in your cup. With a flip flop closure, it can fit a good amount of straw sizes as well as help to stop spills from happening, it also improves cleaning ability.

Read more

Just the Right Size

The size options will be enough to get you through tough and long days. If you are not sure how much of your desired beverage is in your cup after a couple of solid swigs, the shaded lid will help you get an idea of how much you have in your cup. That is super helpful if you need to keep fueled up with caffeine for instance during an all-nighter.

Variance

The variance in size allows anyone to accommodate as much or as little as you need. There are 20 oz, 30 oz., and 40 oz. to choose from and the tall design allows for that extra room for your beverage. The slimness of the cup works well with most cup holders.

Cost and Value

There are over 18 nice color options to chose from and the pricing is moderate. The design is definitely that of RTIC in the way the lid is set up, but some people really prefer this type of click in hold system for the closure.

9. Bottlebottle

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
93
Bottlebottle
Insulation
90
Use
94
Style
95
best offer for today
$16.99
Pros:

Really pretty color options

Colors hold up well and are durable

Double wall insulation

18/8 stainless steel

Cons:

Can be a bit heavy

The bottom can wobble a bit

Bottlebottle makes an 8 oz. cup that is perfect poolside, at the lake, or at the campsite for a nice mixed drink, wine, or a cool and refreshing iced tea. Using 18/8 stainless steel and double wall vacuum seal to keep your drink nice and cool.

Read more

Nice Look

With the glittery space design, you get with pattern one, you can really make an impression. If you need something less psychedelic the Bordeaux red or glacier blue may be your preference. There is always classic stainless steel for those who like the simple, clean look.

Holds Up Well

The color options come in matte and shiny versions and the best part is no matter which you prefer both hold up well to wear and tear. even after months of constant use in the great outdoors they still wash easily and will look just like they did when you first bought them. They can really hold up well which is a nice feature in a rugged wine cup.

Cost and Value

The finish on these cups is very eye-catching and you won't have much problem with it chipping or dulling. Keeping a nice glow is worthwhile when you are floating in the pool taking in the rays. This tends to be a pricier cup but it holds up well.

10. Obstal

The rating is based on the average rating (1-100) from all the criteria in which we rated this product.
90.3
Obstal
Insulation
90
Use
89
Style
92
best offer for today
$13.49
Pros:

A set that comes with 1 tumbler, 1 flexible slider lid, 1 stainless straw, and 1 cleaning brush

This is a set that makes a nice gift

Sweat-proof and condensation-free

Holds the cold up to 6 hours or the hot up to 6 hours

Made of food grade 18/8 stainless steel

Dishwasher safe and won’t leach chemicals

5 powder coated color finishes

Matte Black, Aqua Blue, Burgundy, Fuchsia and Navy

Cons:

The lids could be more secure

Obstal makes a food -grade stainless steel product that is double wall insulated. It makes a nice kit with a straw, slider lid, and cleaning brush. This is a very attractive design.

Read more

Quality Finish

The paint is superior. It is super durable and it would take a lot to get it to peel or chip. So if you are an adventurer or just naturally clumsy, this product may be your best bet to take those hits and bumps along the road.

Well Constructed

The overall shape is put together very smoothly and nicely to the touch. It is very seamless in how the welding is done.
The powder-coated paint is not only attractive but durable. While it may not be a spill-proof option its design can help minimize spillage if knocked over.

Cost and Value

For the low price, you are getting a terrific deal in terms of durability and look. It functions well and can hold up even better. It is certainly worth a try if you don't want to spend a ton and aren't one who needs to boast a popular brand name on all your drinkware.

Criteria Used for Evaluation

Insulation

The method of insulation varies among the different products on the market. Here are three methods to consider:

1. Air insulation, which works pretty well. It will keep your cold drinks cool and help extend the amount of time that your hot beverages will keep their heat. It uses convection which allows for heat to move through the fluid and air can escape upward which can transfer heat. That helps keep surfaces cool.

2. Vacuum insulation is a very effective option. It will do the same thing as air insulation, but it holds temperatures for longer. With this type of insulation, there are two containers used with one inside the other. The resulting gap between the two containers has air that is then removed, or vacuumed out. This allows for a sort of buffer effect that can help maintain temperatures and prevent a significant amount of heat transfer.

3. Copper insulation is going to be your best option for keeping hot beverages super warm. The advantage is in the copper material. Since copper is a tremendous conductor it will absorb heat and send it back into your drinkware making this an effective way to keep hot beverages steaming longer.

Use

If your tumbler is easy to use you will enjoy it much more. If it can fit most cup holders well if it is easy to clean and dry, if it feels good and comfortable in your hands, if it allows for a solid grip, and if it stays dry without condensation you will use your product much more. Some products come with handles for easy carrying and drinking, while others have accessories you can add-on that include a handle. As far as cleaning, many options are dishwasher safe which can save you time, but others that are made for more viscous liquids like smoothies may include a straw brush that you'd want to use in prep before putting through the dishwasher to loosen up and scrub free any debris that can stick to the inner wall.
Then obviously there is the ability of the tumbler to do its job well and keep your beverages cool or hot for an extended period of time. Last, ensuring that there is less ability to splash and spill and that the means to drink and sip from the cup is comfortable and ergonomic; can all work together to ensure a much more pleasant experience with your product.

Style

There is no question that looks matter for most things. Your preferred beverage holder is no exception. The great thing is that most of the brands that are on the market offer a wide range of colors, patterns, and designs that can appeal to most anyone's sensibilities. However, if you are a stickler for the tried and true classic options like white, black, and shiny stainless steel looks, these are always the base for which each product builds their lines.

Expert Interviews & Opinions

Most Important Criteria (According to our experts opinion)
Sort criterias acording to:
Experts Opinion Editors Opinion Users Opinion By Default
Click on a to rate the most important criteria:
#1
Insulation
Rate This Criteria as Most Important
#2
Use
Rate This Criteria as Most Important
#3
Style
Rate This Criteria as Most Important
Hot or Cold

Although not generally necessary, pre-heating or chilling your tumbler assist in to keep your beverage hot or cold longer.

Clean is Healty

Keeping your tumbler clean will keep you healthier and keep your beverages tasting good. Always use a bottle brush to clean your tumbler. Generally, dishwashers, freezer, or microwave use is not recommended for you tumbler.

Other Factors to Consider

Application

The application you use your cup for matters in as far as the effectiveness of holding a certain temperature but also in terms of the capacity of liquid that it can contain. If you are someone who needs to have a consistent partner for all day or night sipping, you are going to want a larger product like a 30 or 40 oz., for instance. If you just need to get in your morning cup of coffee, maybe a simple 12 oz. will do the trick. Then there are the niche products that are made for 8 oz drink such as wine, or refreshing beverages to sip on over a shorter period of time. Either way, there are plenty of options on the market to help you find your perfect size that will fit your lifestyle or favorite activity. If you are out in the rough and you are camping or hiking, looking for an extra large insulated bottle in a 64 oz or even a 72 oz., may be the way to go to keep you hydrated when access to clean drinking water is not easily found.

Frequently Asked Questions

q: What purposes can air insulation be good for?
a:

Very many purposes, all very practical as well. Drink and food coolers can benefit from this technology. Cooking utensils can also be helpful. There is a finite amount of heat transfer when it comes to air, which is a gas, is what makes this type of system a solid insulator.

q: How does heat travel?
a:

There are three ways that heat is transmitted and these are through convection and conduction which can use low-density materials such as trapped air pockets. The third way is radiation where heat is reflected. Foil barriers would be a way in which radiation could work. Whem making use of reflective materials, it is best to be in hot climates or using hot substances that already have heat to expel because this type of heat transfer deals with radiant heat.

q: What temperature is red wine best served?
a:

Less than 70 degrees F. This will tend to be a bit cooler than what the average home's room temperature will be. Keeping the wine at the ideal temperature will allow you to enjoy it to its full extent and get a full appreciation of the levels of flavor your preferred bottle offers.

q: How does ice keep water cool?
a:

If you have a good ratio of water to ice you can keep a longer cooling effect for that water. While some of the ice is melting in the lower temperature of the water, equally, some of the water around the ice is re-freezing from touching the low temperature of the ice. This phenomenon creates an equilibrium state which contributes to keeping your temperature a more constant cool. As the ice melts away over time, the ice will begin to pick up the pace and melt faster because of there
is less of it in the cup. However, not until all the ice has melted away will the temperature of your water increase.

q: How can you raise the temperature of a liquid without adding additional heat?
a:

If you already have a liquid that is hot, say boiling water, it is possible to raise the temperature of that water without increasing the heat applied. If you add pressure you would essentially be confining the steam in a defined, enclosed space. This makes it tough for molecules to change phase. Therefore, they will be stuck in their liquid state even while the water exceeds it's boiling temperature. This is the science that applies to the way pressure cookers work.

q: How does salt effect ice?
a:

Ice will melt with the addition of salt. Salt makes the temperature of the ice cube above the melting point. As melting occurs, it cools down. The bonds that keep ice in its solid state begin breaking down, thus phase changing to a liquid state.

Sources

  1. Zak Designs, the meaning of vacuum insulated, Drinkware Design Company,
  2. Hunker, How is Air an Insulator?, Design Block,
  3. Build, How does insulation work?, Carpentry and Construction Site,
  4. Chemistry Stack Exchange, Why does ice water get colder when salt is added?, Science Forum,