How Much Are Air Leaks Costing You?
The US Department of Energy estimates that air leaks account for 25–40% of the energy used for heating and cooling in a typical American home. Most of that leakage occurs around doors and windows. Sealing these gaps properly can reduce your energy bills by $200–$400 per year — and the materials cost less than $50. Few home improvements have a faster payback period.
Where to Check for Air Leaks
On a cold, windy day, hold a lit incense stick near window and door frames, electrical outlets on exterior walls, and where walls meet floors and ceilings. If the smoke moves sideways, you've found a leak. Alternatively, slide a piece of paper under a closed door — if it moves freely, the door seal needs replacing.
Types of Weatherstripping
Door Sweeps
A door sweep seals the gap between the bottom of the door and the threshold. It's often the largest air leak in the house. Automatic door sweeps retract when the door opens and drop when it closes — they last longer than fixed sweeps because they don't drag on the floor.
V-Strip (Tension Seal)
A folded piece of plastic or metal that springs open to fill the gap between the door/window and the frame. Excellent for the sides and top of doors and double-hung windows. Very durable and virtually invisible when installed.
Foam Tape
Self-adhesive foam tape is the easiest weatherstripping to install but the least durable — it compresses permanently within 1–2 years. Best for rarely-used doors, casement windows, or as a quick temporary fix. Use closed-cell (EPDM rubber) foam, not open-cell foam sponge.
Door Thresholds
If the threshold under your door is worn, cracked, or missing its rubber seal insert, replacing it eliminates one of the biggest draft sources in the house.
Top Products on Amazon
1. M-D Building Products 43996 — Best Door Sweep
The M-D 43996 is an automatic door bottom sweep that lifts off the floor as the door opens and drops to seal when the door closes. The EPDM rubber seal compresses to fill uneven gaps. Cuts easily with a hacksaw to fit any door width. Installs with four screws in about 15 minutes.
2. Frost King DS1-2H — Best V-Strip
Frost King's self-stick vinyl V-strip is the most reliable weatherstripping for door sides and tops. Cut to length, peel the backing, and press into the door stop channel. The spring tension keeps it sealed as long as the door closes properly. A single package seals a standard door for under $10.
3. M-D Building Products EPDM Foam Tape — Best Foam Seal
When foam tape is the right solution (casement windows, hatch doors), M-D's EPDM rubber foam is significantly more durable than generic foam. It retains its shape much longer than cheaper options — the difference between one year and five years of useful life.