Doors Adjacent to Unconditioned Space
No climate specific information applies.
Exterior doorways are essentially large holes in the exterior shell of the home connecting the indoors to the outdoors or to other unconditioned spaces like garages, attics, and porches. However; with proper installation and air sealing, exterior doors do not have to represent a significant source of air leakage and heat loss. Exterior doors are usually sold as a kit with the frame attached. Insulated foam-core, metal or fiberglass ENERGY STAR doors are available and should be selected if possible. When the exterior door is installed in a new house, the rough opening (the space left for the door) is typically 1.5 to 2 inches larger than the door frame to give the installer room to install, plumb, and square the door. Once the door is set in place, some installers will stuff batt insulation into any gaps remaining in the rough opening around the frame. This fiber insulation may provide some insulation value but will not stop air flow. The rough opening should be filled with non-expanding foam or backer rod (a rod-shaped closed cell foam product) and caulk. On the exterior, the door should be properly flashed with adhesive waterproof flashing before siding is installed. The door frame should be weather stripped and a tight-fitting door sweep should be installed along the bottom of the door.
Air sealing could be done by the framer, the insulation contractor, or the contractor who installs the door. This task should be included in the contract for the appropriate trade depending on the workflow at the specific job site.
How to Air Seal the Exterior Doors
- Select doors that are self-closing and fire-rated; consider ENERYG STAR-labeled metal- or fiberglass-clad insulated foam core doors.
- Install the door per the manufacturer’s instructions. Install an automatic door closer. Fill the rough opening around the door with non-expanding foam or press backer rod into the wider gaps and seal the seams with caulk. Flash the door frame with adhesive waterproof flashing that is properly integrated with the wall sheathing and house wrap.
- Install appropriate weather stripping to the door frame and threshold. See the table below for types. To determine how much weatherstripping you will need, add the perimeters of all the doors to be weatherstripped, then add 5% to 10% to accommodate any waste. Weatherstripping should be applied to clean, dry surfaces in temperatures above 20°F (-7° C). Make sure the weatherstripping meets tightly at the corners. Use a thickness that causes the weatherstripping to press tightly between the door and the door jamb when the door closes without making it difficult to shut.
Types of Weatherstripping (DOE 2012):
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.||Varies||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.|
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.|
Closed-cell foam attached to wood or metal strips.
|Door or window stops; bottom or top of window sash; bottom of door.||
|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.|
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-Mod.||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.|
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.||Mod- high.||Relatively easy to install; many types are adjustable for uneven threshold. Automatically retracting sweeps 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.|
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.||Mod- high.||Effective air barrier.||Self-stick versions challenging to install.|
Tubular gasket attached to a metal strip that resembles reinforced tubular vinyl
|On a doorjamb or a window stop.||Mod- high.||Seals well.||Installation can be tricky. Hacksaw required to cut metal; butting corners pose a challenge.|
Aluminum face attachment with vinyl C-shaped insert to protect under the door.
|To seal space beneath door.||Mod- high.||Sheds rain on the exterior, durable. Can be used with uneven opening. Some door shoes have replaceable vinyl inserts.||Fairly expensive; installation moderately difficult. May require door bottom planing.|
Vinyl and aluminum
|Door thresholds.||Mod- high.||Combination threshold and weatherstrip; available in different heights.||Wears from foot traffic; relatively expensive.|
Aluminum or other metal on exterior, wood on interior, with door-bottom seam and vinyl threshold replacement.
|To seal beneath a door.||Mod- high.||The use of different materials means less cold transfer. Effective.||Moderately difficult to install, involves threshold replacement.|
Pile weatherstrip with plastic Mylar fin centered in pile.
|For aluminum sliding windows and sliding glass doors.||Mod- 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.|
Visually inspect exterior doors to see that weather stripping has been installed and that doors fit snugly with no air movement around perimeter or along trim when the door is closed. Verify that doors open freely with no drag on the threshold. Visually inspect that rough openings around door frames are air sealed before the drywall or door trim is installed. Check for air movement around the closed door and door trim with a smoke pencil or hand. Leaks will be easier to detect during a blower door test.
Doors adjacent to unconditioned space (e.g., attics, garages, basements) or ambient conditions gasketed or made substantially air-tight.
- Install a continuous gasket, such as weather stripping, around all exterior door openings.
Thermal Enclosure Checklist, Air Sealing. Doors adjacent to unconditioned space (e.g., attics, garages, basements) or ambient conditions gasketed or made substantially air-tight.
Exhibit 1: Mandatory Requirements. Certified under ENERGY STAR Qualified Homes Version 3.
North American Fenestration Standard/Specification for Windows, Doors, and Skylights. Available from AAMA. This is a voluntary standard/specification that covers requirements for the following components for new construction and retrofits: single and dual windows, single and dual side-hinged door systems, sliding doors, tubular daylighting devices, and unit skylights.
Standard Practice for Installation of Exterior Windows, Doors and Skylights. Available from ASTM. The standard covers fenestration product installation from pre-installation through post-installation procedures in new and existing construction.
Table 402.4.2 Air Barrier and Insulation Inspection Component Criteria, Windows and doors: Seal space between window/door jambs and framing.*
Table N1102.4.2 Air Barrier and Insulation Inspection Component Criteria, Windows and doors: Seal space between window/door jambs and framing.*
Table R402.4.1.1 Air Barrier and Insulation Installation, Windows, skylights and doors: Seal space between window/door jambs and framing and skylights and framing.* Table R402.4.1.1 Air Barrier and Insulation Installation, Narrow cavities: Batts in narrow cavities are cut to fit; or narrow cavities are filled with insulation that readily fills the available cavity space.*
Table N11402.4.1.1 Air Barrier and Insulation Installation, Windows, skylights and doors: Seal space between window/door jambs and framing and skylights and framing.* Table N1220.127.116.11 Air Barrier and Insulation Installation, Narrow cavities: Batts in narrow cavities are cut to fit; or narrow cavities are filled with insulation that readily fills the available cavity space.*
*Due to copyright restrictions, exact code text is not provided. For specific code text, refer to the applicable code.