Home insulation: How to stop air from leaking around a door

If you felt a draft inside your home even though your heater was working overtime, chances are you had cold air leaking into your home from small gaps and cracks around your doors as well as windows. 

These air leaks will make your HVAC system work harder all through the year. Your air conditioner will probably be on full blast through the summer, while warm air comes into your home and cool air escapes through these cracks. In the winters, the opposite happens. While your home’s furnace warms up the building, warm air will escape and make way for cold air.

These persistent air leaks not only strain your HVAC system but also increase heating and cooling costs significantly. Fortunately, sealing air leaks is a manageable home improvement project requiring affordable, easy-to-install materials like caulk and weatherstripping. However, before beginning any insulation work, consult an HVAC technician to ensure that sealing these gaps won’t negatively impact your home’s ventilation and indoor air quality.

Let’s explore practical steps to detect and stop air from leaking around your doors.

Three ways to detect air leaks

Blackout the room

Use blackout curtains on the doors and windows to completely darken the room you think needs the treatment. If you see any light leaking through the corners or from under the door or the windows, rest assured that is where your draft is coming from.

Check the caulk

The purpose of caulking is to seal off any gaps in door and window frames. If you see that the caulking around the door frame is damaged, that is likely the reason your home is drafty. 

The smoke test

For this test to work, first, use a large exhaust fan to suck out all the stale air from the room. Then, turn off all combustible appliances and make sure all the doors and windows are tightly closed.

Then, light an incense stick, a thin piece of tissue paper, or a candle and take the flame close to the border of the doors and windows. If the smoke from the source either blows into the room or is sucked out, it is indicative of a leak around that frame. 

Read more: Air quality testing

Three air sealing tricks

Door draft stoppers

This is a makeshift arrangement at best. Door draft stoppers can be placed at the inner base of the door to create a temporary draft barrier.

Other than acting as a draft barrier, door draft stoppers also block out outside noise to a certain extent. These stoppers are made out of materials such as plastic, Styrofoam, silicone, or fabric. 

Weatherstripping

Weatherstripping or the process of installing weather strips around doors and windows to insulate them is a more permanent solution. 

Also known as door sweeps, weatherstrips are made from a variety of materials, ranging from wood, felt, rubber and vinyl to metals like aluminum and brass.

The most durable weather strips are called compression weather strips and are made of aluminum, wood, or vinyl with a flexible vinyl bulb.

Recaulking

If the caulk around the door has worn out over time, recaulking it is another effective way to seal those air gaps.

This method is best suited for gaps less than ¼ inch wide. All you need is a tube of external caulk and a caulk gun.

• Before you begin recaulking, remove old paint and old caulk from the area. 
• Wipe it clean with a damp rag and let it dry completely before you begin.
• Once you’ve recaulked the area, remember that it will take 24 hours for it to cure.

Bottom line

Stopping air leaks around your doors enhances your home’s energy efficiency, reduces utility costs, and ensures a comfortable indoor environment. By implementing simple measures like weatherstripping, draft stoppers, or recaulked seals, you protect your HVAC system from unnecessary strain and extend its lifespan. Regular maintenance and periodic inspections can keep your home draft-free, saving energy and money in the long run.

Written by Narayan Shrouthy. March 25, 2022

Narayan is a content writer for Kukun. With experience in both content writing and editing, Narayan mixes his writing and love for reading with his passion for music. As an active musician, He aims to be a key player in Kukun's content experience.