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Keep Warmth In (and Insects Out) With DIY Insulating Foam Sealant

It’s a story as old as time (or at least as old as HVAC systems) — you crank up the heat but your home just isn’t getting warm enough during the winter. Often, the culprit is drafts — spots where you can feel cold air seeping into your home through window cracks or doors. But what’s worse than cold air entering is warm air escaping. After all, you probably pay for that warm air every month. Air leaks are a problem in summer too, especially if you have a close relationship with your air conditioner. One of the most economical and effective solutions for drafts comes in the form of insulating foam sealant. The best insulating foam sealant for DIY purposes comes in a handheld can similar to hairspray or spraypaint.

The first step in sealing leaks is identifying them. According to Energy Star, the worst air leaks typically come from the attic or basement. You may find that you need fiberglass insulation for larger gaps, but spray foam insulation is an effective solution for smaller holes around pipes, corners and even outlets. The foam comes out in a thin spray and quickly expands, effectively sealing and filling gaps. Many insulating foam sealants are specifically designed for certain problem areas, so you can choose the one that best suits your needs.

One major benefit of insulating foam sealant is that it also helps block out pests like ants, roaches and spiders — there are even sealants that are specifically designed for this purpose. There are also sealants designed for outdoor use. They can resist weather but will still need to be coated if directly exposed to sunlight. Outdoor sealants are black, meaning that they blend in with shadows rather than standing out like white foam might. It’s more of an aesthetic consideration than a practical one, but it’s a consideration worth making.

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The best insulating foam sealant is easy enough to use for regular consumers and with minimal instructions, but as with any DIY project, safety precautions are necessary. Foam spray is messy, and the cans can leak. Gloves and protective eyewear should always be worn. You should also try to avoid placing the cans directly on the ground when not in use. If you’ve sprayed excess foam, wait for it to dry, then cut it. It will likely be more of a mess if you try to remove the foam while it’s still wet. Ironically, although foam sealants are made to block out air and moisture, they actually need air and moisture to help set. If you’re not getting enough airflow, you can spray a little water to help the foam set.

If you’ve identified the problem areas and you have your gloves, mask and eyewear ready to go, then read on for our picks for the best foam sealants on Amazon.

1. Great Stuff Smart Dispenser Gaps & Cracks

This option features the same standard foaming formula that Great Stuff is known for, but the nozzle has been redesigned. The improved straw and nozzle design is supposed to make it easier to reuse. In fact, it’s listed as being able to be reused for up to 30 days. The straw tip closes once you release the trigger, and this helps reduce foam from dripping out and blocking the opening, a common problem with canned foam sealants. This product fills gaps up to 1″ wide.

Pros: Redesigned nozzle improves the reuse value of this insulating foam for up to 30 days after opening.

Cons: It’s still possible for leaks to occur and for the nozzle to dry out.

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2. Loctite TITEFOAM Insulating Foam Sealant

Loctite’s foam sealant has several features that are designed to make it especially effective and easy to use. It’s supposed to be four times as dense as regular foam sealants, offering extra insulation and blocking air more securely. This particular option comes out as a bright white foam. It also has UV resistance, so it’s designed to resist cracking and darkening. If used outside, however, additional protective covering should be used.

Pros: Designed to be extra dense for additional insulative properties. Affordable value.

Cons: Nozzle can be somewhat leaky. The product can seal inside the applicator after first use if you aren’t careful.

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3. Great Stuff Insulating Foam Sealant Black

Great Stuff makes many of the best insulating foam sealants, and this option is versatile enough for a variety of applications. This multipurpose foam sealant is black, making it a good pick for exterior use. Black foam will blend in better and be less visible than white foam when used on outside pipes and walls, but you can also use this one indoors if necessary. It’s designed for smaller gaps, up to 3/4″.

Pros: Black color is good for discreet outdoor usage. Also suitable for indoor use. Designed to cure quickly.

Cons: Not ideal for larger gaps.

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4. DAP Touch ‘n Foam Expanding Sealant

This option expands more than some of the other picks on this list, making it a good pick for filling any larger gaps you may have. It expands wider than 1″, while many of the options on this list are only suitable for 3/4″ or 1″ gaps. It’s weather-resistant, so it will effectively block out escaping air in addition to keeping moisture out. It comes out as a cream/tan color.

Pros: One of the widest expansions of the options on this list, making it suitable for use on larger gaps. Good for outdoor or indoor use.

Cons: It’s listed as reusable, but it’s more difficult to use the second time.

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5. Great Stuff Pestblock 12 oz Insulating Foam Sealant

This option from Great Stuff is specifically formulated for blocking out insects. It also works well for regular insulation purposes, too. It expands up to 1″, while some others on this list only expand 3/4″. A bittering agent inside the sealant deters pests like ants and wasps from chewing on the foam. There are no pesticides included, so it’s non-toxic and won’t harm bees.

Pros: Bittering agent helps deter pests from chewing on the foam; non-toxic formula is free of pesticides.

Cons: Additional measures may be needed if dealing with rodents.

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6. Great Stuff Gaps & Cracks 20 oz Insulating Foam Sealant

This option from Great Stuff is a good general-purpose option for gaps and cracks. It seals holes up to 1″ wide to help block drafts and insulate. It comes out as an off-white color. Most of the options on this list come in a 12 oz can, but this option is a 20 oz can. That makes it a good pick for any larger jobs you may have to do. Like many Great Stuff foam sealants, this one is designed to go on easily and dry quickly.

Pros: Value 20 oz size. Good general purpose option. FIlls gaps up to 1″ large.

Cons: Like most foaming sealant, it’s difficult to use more than once. The 20 oz canister may not be a good value if only have a small project.

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7. Dow Chemical Expanding Foam Sealant, 20 Oz.

Dow Chemical is best known for its industrial chemicals and products, but this is a great DIY product from a trusted manufacturer. This Fill and Seal triple-expanding sealant can be used to prevent drafts and pest incursions into your home. This tan-colored sealant will expand to three times the applied volume and forms an air-tight and waterproof bond. This product can be used on wood, metal, masonry, glass and plastics. This Fill and Seal foam will dry tack-free within 15 minutes and fully cure within eight hours.

Pros: This product can be used on a wide variety of indoor and outdoor materials. Triple-expanding formula is suitable for cracks larger than 3/4″.

Cons: Can be difficult to apply after initial use; color is not particularly attractive.


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8. Great Stuff PRO Window & Door 20 oz Insulating Foam Sealant

Windows and doors can be a major source of heat loss, but foaming sealant can sometimes be risky to use. If it expands too much, it may be harder for you to actually open and close windows and doors. That’s where this option comes in. It’s made to be minimally expanding and low-density, reducing the risk of bending the frames of windows and doors. Unlike most of the other options, a dispensing gun is needed. It’s sold separately by Great Stuff and other retailers.

Pros: Minimally expanding and low pressure, making it suitable for use on windows and doors without obstructing their normal operation. Large 20 oz can.

Cons: Spray gun attachment is required, and it is sold separately.

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