door bottom and door sweep weatherstrips
Air sealing the gap at the bottom of a door - a typical major source of air leakage - is different from sealing the gaps at its sides and top. And it demands different materials: door thresholds, door sweeps and door bottoms...
Door sweeps & Thresholds
Common door sweeps are made from aluminum or stainless steel and have a brush of vinyl, plastic, felt or sponge; some are retractable - to reduce drag on the floor covering or carpets.
Door sweeps are relatively easy to install. They just have to be mounted (using screws or nails) at the bottom of the door's interior side (in the case of in-swinging doors) or exterior side (in the case of out-swinging doors). Self-adhesive sweeps aren't recommended.
It’s possible to use door sweeps without a threshold, but that’s not an efficient solution. Without a threshold the sweep will easily become too ineffective and prone to wear. To last longer and to be effective, sweeps have to contact the edge of a threshold as the door shuts.
Door sweeps vs. door bottoms
Door bottoms are, most of the times, a better solution than door sweeps. Door sweeps are easier to install but since they hang below the door, they are more prone to drag on the floor and more subject to wear and tear, which causes a lower durability.
Still more important, their design is less effective. Door sweeps can be a reasonable solution to stop air leakage, but just that. Good bottom door weatherstrips are more effective at blocking air leaks than sweeps…
Thresholds with imbedded weatherstripping
Some door thresholds can be imbedded with weatherstrips and mounted in order to contact the edge of the bottom of the door without the use of a door bottom or a door sweep.
That’s an option, but this type of weatherstripping accumulates more dirt and is more prone to the foot traffic damage and wear. There are better weatherstripping solutions…
Finned door bottom weatherstrips
This door weather-strip is easy to install. The door bottom involves a vinyl strip with fins to contact the threshold. This system isn’t expensive, and since it uses several fins, the damage of one doesn't compromise the sealing of the whole.
Interlocking channels weatherstripping
Interlocking metal channels weatherstrips are perhaps the best air sealing system for the bottom of the doors.
They are very durable and very effective, due to their exceptional design. See image. The disadvantage is that they are relatively expensive and the alignment of the interlocking channels is critical, demanding a professional installation.
Door Shoe weatherstripping
Door shoe weatherstrips use a vinyl insert or sponge rubber tubes. See image. Prices are lower than those of interlocking channel weatherstrips, but relatively high anyway. These door weatherstrips are very durable and very effective (though less than interlocking channel units). Vinyl inserts are replaceable, and the installation is not as difficult as that of interlocking channels.
See also:
Weatherstripping Materials for Doors
Door Threshold Weatherstripping
Stop and Jamb Door Weatherstripping
Advanced energy-efficient doors
Exterior Door Types
Factory-Made Pre-Hang Doors
Exterior Door Manufacturers
The Best of Doors