Thermwell

THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape 2-1 4 by 2-1 4 by 42-Inch

1759+ bought in the past month

$3.94$5.99

About this item

  • For Weather-Stripping Around Window Air Conditioners
  • Resilient, Compressible Strip For Sealing Out Air, Insects & Dust
  • Open Cell Foam Tape
$3.94
Was $5.99Save $2.05

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Product details

BrandThermwell
MaterialFoam
ColorGray
Product Dimensions42"L x 2.25"W
Item Thickness2.25 Inches

Technical specifications

brandThermwell
materialFoam
colorGray
product_dimensions42"L x 2.25"W
item_thickness2.25 Inches
recommended_uses_for_productWindow
upc077578030401
number_of_items1
global_trade_identification_number00077578030401
manufacturerThermwell Products Co., Inc
unit_count3.5 Feet
item_weight0.01 ounces
item_model_numberAC43H
best_sellers_rank#2,139 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #14 in Weather Stripping
is_discontinued_by_manufacturerNo
perfumeUnscented
assembly_requiredNo
warranty_descriptionManufacturer's warranty against defects.
batteries_requiredNo
included_componentsFoam Insulation

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Customer reviews

4.63,127 ratings

Customers say

Customers find the weather stripping works well for window units and effectively seals air conditioners, keeping hot air from seeping through windows. Customers consider it good value for money and praise its secure seal for window AC units.

★★★★★

A Solid Weatherseal Upgrade for Window Air Conditioners

mvepaoijg90r8January 3, 2026✓ Verified purchase

The THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape is a simple but highly effective solution for sealing window AC units and eliminating the drafts, vibration noise, and dust gaps that tend to show up around older installations. The foam is dense enough to provide a firm, reliable seal, yet still compresses easily to fit uneven gaps without tearing or crumbling. At 2‑1/4 by 2‑1/4 inches and 42 inches long, the size is generous and works well for both side and top gaps on standard window units. During installation, the adhesive held securely without needing reinforcement, and once in place, the foam stayed put even through temperature swings and daily AC vibration. The material also rebounds well, maintaining its shape rather than flattening out over time. For anyone installing a new unit or tightening up an existing one, this weatherseal tape offers dependable performance, easy handling, and a noticeable improvement in insulation and noise reduction. Read more

Review image 1Review image 2
★★★★★

Perfect for around my a/c unit

Colleen FitzgibbonFebruary 25, 2026✓ Verified purchase

I buy this product every year to put around my a/c unit. It’s nice and wide so perfect for the job. Read more

★★★★★

Good for Starlink Cable Passthrough

Kevin der KinderenFebruary 11, 2026✓ Verified purchase

I purchased this to protect my startlink cable I have running through the window and to block out the outside. I folded over a piece so the cable was sandwiched and this put another piece up where the windows separate. As for insulation, we had a cold snap here in Virginia and it I felt no air or coldness making it through. Also, it seems to protect the cable quite well rather than letting wood press directly against it. I was going to make this a temporary setup but see no need to change it. The weather seal is working just fine. Read more

★★★★☆

"Tape" is false, "Foam Strip" is correct

RichManSCTVJune 20, 2024✓ Verified purchase

First let me address this saying this is not TAPE. There is no sticky adhesion on it, nothing like a 3m tape that you remove some plastic and stick it on. This is just a foam strip. With that being said.... Its a GREAT one ! Perfect for that gap at the bottom of the air conditioner. Its too thick for the gap at the top of the open window but it is PERFECT for the large gap under the air conditioner. The weight of the unit compresses it and blocks all possible gaps. Read more

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★★★★★

Excellent for Sealing Space Between Windows After AC Installation

LFSeptember 25, 2025✓ Verified purchase

I purchased this to fill the space between two windowpanes in a side-to-side sliding window after installing a window air conditioner. There was about an inch of space between the panes in a high wind area with typical winds of 20mph and frequent 30mph gusts in normal weather conditions. Everything I tried quite literally blew right out of place. I decided to give this a try and ordered the 2-1/4 inch size, so that I had plenty of room to squish it down and let it expand into place. It worked great! It was easy to install. I just pressed it down as sliding into place a little at a time and then adjusted it to make sure it was straight and aligned with the window to ensure it looks nice. The foam is sturdy, yet easy to squish to install. It took less than 5 minutes to seal both window spaces inside and outside. It expanded into place and is tightly packed. The winds (and dirt they bring) don't stand a chance! Read more

★★★★★

Great product for insulation!!

WitchyWomanSeptember 10, 2025✓ Verified purchase

Arrived as stated and does the job I bought it for. I use these for around my window a/c unit but I also live in a VERY old apt that has many cracks! These can be cut easily for use in sealing cracks around old windows in conjunction with the plastic I also use and these work wonderfully. Easy to install and I suggest the grey. Good quality! Good packaging! Great seller! Recommend!! Read more

★★★★★

Other use of the foam.

dde123January 11, 2026✓ Verified purchase

This stuff works well to stop the flow of heat out of a hot water register. I have hot water heat and one of the rooms is between heated walls. It doesn't need much heat. So I closed it off by stuffing the foam under the register. There is no fire danger because the water flowing in the register pipe is max 180 degrees. Read more

★★★☆☆

Measure first

CustomerFebruary 3, 2026✓ Verified purchase

This product seems good I guess, great price, but i didn't measure my windows, and thought it would be squishier and it didn't fit Read more

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