KS Hardware , Patent Pending, Adjustable Double Bubble Door Sweep, Draft Stopper, Under Door Seal for Exterior Doors, 1 3/4" x 36"

Why I Replaced My Old Sweep

A persistent draft at my side entry finally pushed me to swap out the tired, single-fin sweep I’d been living with. The door gap was a shade over half an inch—too much for stick-on brushes and not quite even across the width. I wanted a sturdier, more adjustable solution with better threshold contact and protection from wind-driven rain. That’s what led me to the KS Hardware door sweep, a double-bubble, under-door design with an integrated drip cap and a clean screw cover. After several weeks on the door through a mix of cold mornings, wet days, and constant daily opens, it has proven to be a substantial upgrade.

Design and Materials

This sweep mounts under the door and seals against the threshold using two resilient “bubble” fins. That double-bubble profile is the headline feature—two compressible contact points provide redundancy and a broader sealing zone than single-fin or brush-style sweeps. In practice, this means you can dial in a light, continuous compression across a slightly uneven threshold and still get a solid seal.

The body is a rigid, non-metallic extrusion with a separate, snap-on/snap-off screw cover for the interior side. I appreciate the plastic chassis for two reasons: it doesn’t telegraph outdoor cold or heat like aluminum can, and it’s quiet—no metallic tick or scrape if the door flexes a bit. The exterior face integrates a drip cap that projects a small lip to shed water away from the door/threshold interface. It’s a modest detail that becomes a big deal in heavy rain; the threshold stays drier.

The model I installed is the 36-inch black version. It’s a clean, understated look. The flush screw cover hides fasteners for a tidy finish that feels more like part of the door than an add-on.

Fit and Adjustment Range

Adjustment is where this sweep separates itself. It’s designed to accommodate door-to-threshold gaps from roughly 3/8 inch up to 7/8 inch. That covers the most common exterior door scenarios. Each screw slot provides vertical play, which lets you micro-tune the compression of the bubbles. My target is consistent, light contact—enough to stop light and air without creating drag. If you can slip a business card under the sweep in one corner but not elsewhere, keep tweaking. With two contact points, you can tolerate a threshold that’s a bit crowned or low at one side.

A caveat: if your gap is tighter than 3/8 inch, you may fight binding; if it’s larger than 7/8 inch, you’re asking the seal to bridge too far and it won’t perform as intended. Measure before you buy, and assess any threshold irregularities. If the door or frame is significantly out of square, no sweep will completely mask that, but the double-bubble design does a better job than most at compensating for minor inconsistencies.

Installation Experience

This was a straightforward install, but a few steps made it smoother:

• Pull the door. You can technically install in place, but laying the door across sawhorses makes the fit-up and alignment far easier.
• Slide off the interior screw cover before you do anything else. It’s meant to slide lengthwise off the track; don’t try to pry it outwards. Keep it somewhere clean so it glides back on later.
• Orient the sweep correctly. Screws face the interior. The drip cap faces outdoors.
• Dry-fit first. Place the sweep under the door, center it, and lightly clamp or tape it so it won’t creep while you hang the door to test.
• Set the end screws first. With the door re-hung, gently lift or lower each end to achieve the lightest uniform compression on the bubbles. Then add the center screws and fine-tune.
• Use the right pressure. On steel doors, the included screws will self-tap, but a small pilot hole (around 3/32 inch) makes life easier and reduces the chance of stripping.
• Reinstall the screw cover by sliding it on from one end. After the screws are set, the cover track tolerances get tighter. A drop of mild dish soap or silicone spray on the track helps. If it’s stubborn, a wood block and a light mallet tap will persuade it without marking the finish.

Before final tightening, I ran a “light test” by turning off the interior lights and looking for daylight at the threshold. Then a tissue test: holding a tissue near the bottom of the closed door on a breezy day. No movement = no draft.

Total working time was under 30 minutes including door removal and re-hanging. Expect a bit more if you’re drilling pilot holes or fussing with an uneven threshold.

Performance

Sealing: The double-bubble contact is the real win. It eliminated visible light gaps and cut the draft to the point where the entryway temperature no longer swings noticeably. With the HVAC cycling, the area near the door now matches the adjacent room within a degree or two on cold mornings.

Water management: The drip cap does its job. During a long, wind-blown rain, the threshold stayed relatively dry, and I didn’t see water pushing past the sill line. That helps not just with comfort but with finish longevity on the interior floor in front of the door.

Noise and dust: This isn’t a dedicated acoustic seal, but removing the under-door air path does reduce street noise a bit and noticeably cuts dust and leaf fragments that used to sneak under.

Operation: With proper adjustment, the door closes smoothly with a solid, cushioned feel. If you over-compress the bubbles, you’ll know—there’s extra closing resistance and sometimes a faint rubber squeak. A thin wipe of silicone-safe lubricant (or even a tiny bit of petroleum jelly) on the contact edge will quiet that.

Pest resistance: A tight sweep is a basic but effective line of defense. I’ve seen fewer small insects making it under the door since installing it.

Durability and Maintenance

The bubbles are thick and springy, with a nice memory. After daily use, I’ve seen no cracking or permanent set. The rigid body hasn’t scuffed or warped, and the screw cover remains snug. Because the chassis isn’t metal, there’s no thermal bridging and no corrosion concerns. I do recommend:

• Cleaning the threshold before installation and seasonally thereafter. Grit accelerates wear.
• Rechecking screw tightness after the first week. Materials settle slightly.
• Wiping the contact edge if you notice squeak or drag.

Quirks and Limitations

• Screw cover fit: The cover is tight. Sliding it on from the end is the right move; trying to snap it across its width is frustrating. Lubrication helps. If the track distorted after tightening, a mallet and wood block can nudge it into place. It looks great once seated, but be patient.
• Out-of-square doors: If your door is crooked or the threshold isn’t parallel, you may feel extra closing resistance until the bubbles take a set. Work the adjustment carefully and aim for minimal compression.
• Gap range: The specified 3/8 to 7/8 inch range is real. Outside that, choose a different approach—raise/lower the threshold, plane the door, or select another seal type.

Value

This sweep costs more than big-box single-fin options, but the performance is on a different level. Between the dual seals, the under-door adjustability, and the drip cap, it checks boxes that cheaper sweeps don’t. The finished look—with the hidden screws—is a bonus if you care about interior details.

Who It’s For

• Homeowners with exterior doors showing daylight or drafts at the bottom
• Garages or utility rooms that need better thermal separation from the outdoors
• Anyone dealing with a slightly uneven threshold who wants a forgiving, adjustable seal
• People who prefer a cleaner look with concealed fasteners

If your gap is tiny, your door is highly warped, or you need specialized acoustic or fire-rated sealing, look elsewhere. Otherwise, this is a robust, thoughtful solution for everyday exterior doors.

Recommendation

I recommend the KS Hardware door sweep. The double-bubble design provides a consistently tight seal across real-world thresholds, the integrated drip cap improves weather defense, and the under-door adjustability makes dialing in the fit straightforward. Installation is approachable for DIYers—the only fussy part is the screw cover, which rewards a “slide, don’t snap” approach and a little patience. For cutting drafts, keeping out water, and giving an exterior door a finished, professional look, it’s a smart upgrade that just works.