---
product_id: 16882158
title: "THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape, 2-1/4 by 2-1/4 by 42-Inch"
brand: "thermwell"
price: "$29.73"
currency: USD
in_stock: true
reviews_count: 8
category: "Thermwell"
url: https://www.desertcart.us/products/16882158-thermwell-frost-king-ac43h-air-conditioner-weatherseal-tape-2-1
store_origin: US
region: United States of America
---

# 2.25" thickness for robust sealing Open cell foam blocks air, dust & insects 42" length covers standard window gaps THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape, 2-1/4 by 2-1/4 by 42-Inch

**Brand:** thermwell
**Price:** $29.73
**Availability:** ✅ In Stock

## Summary

> 🛠️ Seal smart, live cool — don’t let drafts crash your vibe!

## Quick Answers

- **What is this?** THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape, 2-1/4 by 2-1/4 by 42-Inch by thermwell
- **How much does it cost?** $29.73 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/16882158-thermwell-frost-king-ac43h-air-conditioner-weatherseal-tape-2-1)

## Best For

- thermwell enthusiasts

## Why This Product

- Trusted thermwell brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Durable & Resilient:** Foam rebounds to maintain shape, resisting flattening and wear over time.
- • **Noise & Draft Blocker:** Effectively reduces drafts, dust intrusion, and vibration noise around window AC units.
- • **All-Weather Performance:** Stays firmly in place through temperature swings and daily AC vibrations.
- • **Easy, No-Fuss Installation:** Self-adhesive backing sticks securely without extra tools or reinforcement.
- • **Precision Fit, Maximum Seal:** Generous 2.25" thickness compresses to fill uneven gaps flawlessly.

## Overview

The THERMWELL Frost King AC43H Weatherseal Tape is a 42-inch long, 2.25-inch thick open cell foam strip designed for window air conditioner weather-stripping. It provides a resilient, compressible barrier that seals out air, insects, dust, and noise, improving insulation and comfort. Easy to install with strong adhesive, it maintains its shape and effectiveness through temperature changes and vibrations, making it a reliable upgrade for any window AC setup.

## Description

Product Description 2-1/4" x 2-1/4" x 42", Dark Gray, Open Cell Foam Tape, For Weather-Stripping Around Window Air Conditioners, A Resilient, Compressible Strip For Sealing Out Air, Insects & Dust.Do not use it on paint or wallpaper. Manufacturer Contact Information 1-800-526-5265

Review: A Solid Weatherseal Upgrade for Window Air Conditioners - 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.
Review: Excellent for Sealing Space Between Windows After AC Installation - 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!

## Features

- For Weather-Stripping Around Window Air Conditioners
- Resilient, Compressible Strip For Sealing Out Air, Insects & Dust
- Open Cell Foam Tape

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0000DH4JL |
| Assembly required | No |
| Batteries required | No |
| Best Sellers Rank | #5,229 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #52 in Weather Stripping |
| Brand | Thermwell |
| Color | Gray |
| Customer Reviews | 4.6 4.6 out of 5 stars (3,096) |
| Global Trade Identification Number | 00077578030401 |
| Included Components | Foam Insulation |
| Is Discontinued By Manufacturer | No |
| Item Thickness | 2.25 Inches |
| Item Weight | 0.01 ounces |
| Item model number | AC43H |
| Manufacturer | Thermwell Products Co., Inc |
| Material | Foam |
| Number of Items | 1 |
| Perfume | Unscented |
| Product Dimensions | 42"L x 2.25"W |
| Recommended Uses For Product | Window |
| UPC | 077578030401 |
| Unit Count | 3.5 Feet |
| Warranty Description | Manufacturer's warranty against defects. |

## Product Details

- **Brand:** Thermwell
- **Color:** Gray
- **Item Thickness:** 2.25 Inches
- **Material:** Foam
- **Product Dimensions:** 42"L x 2.25"W

## Images

![THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape, 2-1/4 by 2-1/4 by 42-Inch - Image 1](https://m.media-amazon.com/images/I/81dtEN7daQL.jpg)

## Available Options

This product comes in different **Size** options.

## Questions & Answers

**Q: can the weatherseal go between the bottom of the air conditioner and the window sill?)**
A: If there is space then yes. It’s a foam so you can manipulate it into the smallest crevices.

**Q: does it absorb moisture?**
A: Never had to experience moisture

**Q: What is the maximum temperature rating of this foam?**
A: Sorry, no idea. I use it for insulation. It does not come with temperature ratings listed,  but as it's very light, thick sponge rubber I wouldn't think it would withstand very high heat.

**Q: Is it washable?**
A: It can be hand-washed in mild soapy water' rinsed and air-dried as long as the foam has not gotten crumbly with age.

## Customer Reviews

### ⭐⭐⭐⭐⭐ A Solid Weatherseal Upgrade for Window Air Conditioners
*by M***8 on January 3, 2026*

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.

### ⭐⭐⭐⭐⭐ Excellent for Sealing Space Between Windows After AC Installation
*by L***F on September 25, 2025*

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!

### ⭐⭐⭐⭐⭐ Great product for insulation!!
*by W***N on September 10, 2025*

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!!

## Frequently Bought Together

- THERMWELL Frost King AC43H Air Conditioner Weatherseal Tape, 2-1/4 by 2-1/4 by 42-Inch
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- Breeze Stop Surround Insulation Side Panels White for Window AC Unit Indoor Air Conditioner Cover for Winter and Summer

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-02-19*