Weatherstripping is a material used to seal gaps around windows and exterior doors. Floors, walls, ceilings, and doors and windows all combine to make up the "energy envelope" of your home. Caulking seals the small cracks and holes in the envelope; weatherstripping seals around doors and windows to help make your home airtight.

 

Weatherstripping and caulking are probably the least expensive, simplest, most effective ways to cut down on wasted energy in the winter and summer. Improperly sealed homes can squander 10 to 15 percent of the homeowner's heating dollars and reduce the effectiveness of air-conditioning in the summer.

 

While some new doors now come with factory-applied weatherstripping, such designs are a recent innovation. Millions of doors across the country have little or no weatherstripping. Since most doors have a space – sometimes as much as a quarter inch or more – between the bottom of the door and the floor, large amounts of air can flow in and out of the house. For a typical 36-inch entry door, a quarter-inch small crack can leak as much air as a nine-square-inch hole in the wall.

 

Weatherstripping comes in many forms, and can be made up of a combination of materials such as wood, rubber, vinyl, metal and foam. Some types work well on both doors and windows, while others are more limited.

 

V-strip

A long strip folded back on itself along its length, this type of weatherstripping can be made of either metal or vinyl. It forms a springy strip that bridges the gap between a door and the door jam – or a window sash and the window frame – to prevent the movement of air. Durable, long-lasting and easy to install, V-strips come with a pressure sensitive adhesive; once you have cut a strip to the proper length, you can stick it in place on the frame without the use of tools.

 

Adhesive-backed foam or tape

This material, made from rubber, foam or sponge rubber, can be installed in the same manner as V-strip to help seal doors and windows. Hardware stores sell it in various widths and thicknesses, and the tape is self-adhesive and easy to install. Simply cut the tape to the length you need with scissors, peel away the backing from the tape and stick it in place. The size and flexibility of tape make it well suited for blocking irregular-sized cracks. It wears out quickly, however, and needs to be replaced often – probably every one to two years.

 

Felt

Felt, either plain or reinforced with a flexible metal strip, is sold in rolls that must be cut to length and stapled or tacked into place. Plain felt should be fitted in a door jamb so that the door presses against it; reinforced felt can be used to seal around both doors and windows. Felt traditionally lasts one to two years before it needs to be replaced. A variation on felt is pile, a carpet-like material that can be glued or tacked in place. It comes in narrow, furry strips.

 

Interlocking metal

This is the best, most complex, most expensive weatherstripping. Think of two V-strips that are placed on the door and the door frame. When the door closes, the two pieces interlock to make a tight seal. Interlocking pieces are placed completely around the perimeter of the door – on the top, both sides and the bottom. Installing interlocking weatherstripping can be tricky, since both the door and the frame must be notched with a router. That's why this type of installation is usually done by professionals.

 

Tubular rubber and vinyl gaskets

Small tubes of sponge rubber or vinyl can also be used to weatherstrip around doors and windows. When the door presses against the gasket, it forms a tight seal. By pressing against these gaskets, the door forms a seal. The tubes come with a flange that can be tacked or stapled to hold them in place. Usually they last five years or more.

 

Thresholds

The floor underneath a closed exterior door usually has a raised seal called a threshold. Many thresholds have weatherstripping built in. One style includes a tubular gasket seal built into the threshold that presses against the bottom of the door to keep out drafts. Other threshold weatherstripping is mounted on the door itself. One style called a door sweep features a flexible flap that seals against the threshold.

 

Wall sockets / outlets / switches

There's a final place in your home we need to mention when it comes to weatherstripping – electric wall sockets and switches. Although they aren't in the same category as doors and windows, the holes in our walls for electrical outlets and switches do allow cold air into a house in the wintertime and leak cool, air-conditioning air in the summer. It's a good idea to purchase simple-to-install, pre-cut foam gaskets that fit behind the switch or plug plate to effectively reduce leaks.

 

Weatherstripping types and uses
Weatherstripping	Best uses	Cost	Advantages	Disadvantages
Tension seal: Self-stick plastic (vinyl) folded along length in a V-shape or a springy bronze strip (also copper, aluminum, and stainless steel) shaped to bridge a gap. The shape of the material creates a seal by pressing against the sides of a crack to block drafts.	Inside the track of a double-hung or sliding window, top and sides of door.	Moderate; varies with material used.	Durable. Invisible when in place. Very effective. Vinyl is fairly easy to install. Look of bronze works well for older homes.	Surfaces must be flat and smooth for vinyl. Can be difficult to install, as corners must be snug. Bronze must be nailed in place (every three inches or so) so as not to bend or wrinkle. Can increase resistance in opening/closing doors or windows. Self-adhesive vinyl available. Some manufacturers include extra strip for door striker plate.
Felt: Plain or reinforced with a flexible metal strip; sold in rolls. Must be stapled, glued, or tacked into place. Seals best if staples are parallel to length of the strip.	Around a door or window (reinforced felt); fitted into a door jamb so the door presses against it.	Low	Easy to install, inexpensive.	Low durability; least effective preventing airflow. Do not use where exposed to moisture or where there is friction or abrasion. All-wool felt is more durable and more expensive. Very visible.
Reinforced foam: Closed-cell foam attached to wood or metal strips.	Door or window stops; bottom or top of window sash; bottom of door.	Moderately low	Closed-cell foam an effective sealer; scored well in wind tests. Rigid.	Can be difficult to install; must be sawed, nailed, and painted. Very visible. Manufacturing process produces greenhouse gas emissions.
Tape: Nonporous, closed-cell foam, open-cell foam, or EDPM (Ethylene Propylene Diene Monomer) rubber.	Top and bottom of window sash; door frames; attic hatches and inoperable windows. Good for blocking corners and irregular cracks.	Low.	Extremely easy to install. Works well when compressed. Inexpensive. Can be reinforced with staples.	Durability varies with material used, but not especially high for all; use where little wear is expected; visible.
Rolled or reinforced vinyl: Pliable or rigid strip gasket (attached to wood or metal strips.)	Door or window stops; top or bottom of window sash; bottom of a door (rigid strip only).	Low to moderate.	Easy installation. Low to moderate cost. Self-adhesive on pliable vinyl may not adhere to metal; some types of rigid strip gaskets provide slot holes to adjust height, increasing durability. Comes in varying colors to help with visibility.	Visible.
Door sweep: Aluminum or stainless steel with brush of plastic, vinyl, sponge, or felt.	Bottom of interior side of in-swinging door; bottom of exterior side of exterior-swinging door.	Moderate to high.	Relatively easy to install; many types are adjustable for uneven threshold. Automatically retracting seeps also available, which reduce drag on carpet and increase durability.	Visible. Can drag on carpet. Automatic sweeps are more expensive and can require a small pause once door is unlatched before retracting.
Magnetic: Works similarly to refrigerator gaskets.	Top and sides of doors, double-hung and sliding window channels.	High	Very effective air sealer.
Tubular rubber and vinyl: Vinyl or sponge rubber tubes with a flange along length to staple or tack into place. Door or window presses against them to form a seal.	Around a door.	Moderate to high.	Effective air barrier.	Self-stick versions challenging to install.
Reinforced silicone: Tubular gasket attached to a metal strip that resembles reinforced tubular vinyl	On a doorjamb or a window stop.	Moderate to high.	Seals well.	Installation can be tricky. Hacksaw required to cut metal; butting corners pose a challenge.
Door shoe: Aluminum face attachment with vinyl C-shaped insert to protect under the door.	To seal space beneath door.	Moderate to high.	On the exterior, product sheds rain. Durable. Can be used with uneven opening. Some door shoes have replaceable vinyl inserts.	Fairly expensive; installation moderately difficult. Door bottom planning possibly required.
Bulb threshold: Vinyl and aluminum	Door thresholds	Moderate to high.	Combination threshold and weatherstrip; available in different heights.	Wears from foot traffic; relatively expensive.
"Frost-brake" threshold: Aluminum or other metal on exterior, wood on interior, with door-bottom seam and vinyl threshold replacement.	To seal beneath a door.	Moderate to high.	The use of different materials means less cold transfer. Effective.	Moderately difficult to install, involves threshold replacement.
Fin seal: Pile weatherstrip with plastic Mylar fin centered in pile.	For aluminum sliding windows and sliding glass doors.	Moderate to high.	Very durable.	Can be difficult to install.
Interlocking metal channels: Enables sash to engage one another when closed	Around door perimeters.	High.	Exceptional weather seal.	Very difficult to install as alignment is critical. To be installed by a professional only.

 

Application

Weatherstripping supplies and techniques range from simple to the technical. Consult the instructions on the weatherstripping package. Here are a few basic guidelines:

 

Weatherstripping should be applied to clean, dry surfaces in temperatures above 20°F (-7°C).

Measure the area to be weatherstripped twice before you cut anything.

Apply weatherstripping snugly against both surfaces. The material should compress when the window or door is shut.

 

When weatherstripping doors:

 

Choose the appropriate door sweeps and thresholds for the bottom of the doors.

Weatherstrip the entire door jamb.

Apply one continuous strip along each side.

Make sure the weatherstripping meets tightly at the corners.

Use a thickness that causes the weatherstripping to tightly press between the door and the door jamb when the door closes, without making it difficult to shut.

 

For air sealing windows, apply weatherstripping between the sash and the frame. The weatherstripping shouldn't interfere with the operation of the window.