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Concentration of CO2 in the Atmosphere

DIY Energy Upgrades: Doors

Steel, aluminum and plastic brush sweeps, door shoes on lower right.

Dave Keefe

It sure is annoying when your exterior doors leak a bunch of air – cold air in, or your warm air out, or both – but there are things you can do to tighten them up.

First, consider a storm door if you don’t have one. Storm doors protect your primary door by keeping the weather off it, and they provide another layer between you and the winter chill. Many people love to open the primary and let the sun in through the storm door on pleasant days. Choose one with “Low-E” glass. That means it has an invisible coating that reflects more of the heat back into the house.

Before weather-stripping a door, make sure it operates smoothly and latches properly. This may involve tightening or replacing hinge screws. Reposition the strike plate (the metal device on the frame that the door latch slides into) if needed. Some strike plates are made of two pieces and are adjustable. Sometimes additional hardware items can help tighten an old door, but be sure that the door is still safe.

If you have a newer home or replacement doors, they are probably so-called “pre-hung,”, which means they come from the factory already installed in their jambs and often with trim. These frames commonly have a weather stripping, commonly of vinyl, on the sides and top. It is inserted into a slot and can be removed and replaced easily if it has become worn or has been torn up by the cat. If you have a steel door, you might have magnetic weather strips like that on your refrigerator. It can be replaced in the same way.

Pre-hung doors commonly have adjustable thresholds. Open the door and look down. See those three Phillips screws? They move the threshold up and down.

From left: polypropylene V-seal, EPDM rubber, vinyl-coated foam, silicone, magnetic.

Door weather strips come in a variety of materials and shapes. The inexpensive aluminum and solid vinyl ones may not be the best choice. Vinyl flaps or bulbs aren’t soft enough to seal well and they deteriorate in the sun. A better choice is vinyl-coated foam, EPDM rubber, or silicone.

Weather strips are either compression seals or wipe seals. Compression seals, where the moving part pushes directly down on the seal without sliding across it, should be soft and squishy and are best made of rubber or silicone. Wipe seals, where the parts slide against each other, need to have low friction and are best made of polyethylene, nylon brushes or silicone. You might have old ones made of brass.

If you have older doors, they might have steel interlocking weather strip on the door and the frame (which works OK if it’s not too beat up), or they might have layers of foam strips, or they might have nothing. The vinyl-coated foam mentioned above (the most popular brand is called “Q-Lon”) is also available mounted in a wood or metal strip that can be nailed onto the stop (the piece that the door hits when you close it) or can replace the stop altogether.

You can also use a soft seal on the existing stop, and a polyethylene V-shaped seal (such as Schlegel Polyflex or 3M V-seal) mounted on the frame to contact the door when it is closed. These can respond well to drafts: the ‘v’ is forced to open wider, blocking drafts.

For the bottom of the door, you can choose a door shoe or a door sweep. A shoe wraps around the bottom of the door and has fins or bristles to contact the threshold when the door is closed. A sweep mounts on the inside or outside of the door. In general, a brush-type seal is preferable to a flap, because it conforms to irregular surfaces better and doesn’t drag on the floor as much. Sometimes in older homes the floor is uneven and there’s no room under the door when it opens. In that case, you can get a sweep that has a mechanism to lift the seal when the door opens and lower it when the door is closed.

Don’t forget about the frame and trim. Caulk any cracks in the frame, where the trim meets the frame and wall, and where the threshold meets the floor.

Don’t forget the door leaf itself. Especially with older wooden doors, cracks can develop in the wood panels or joinery. These can usually be fixed by caulking neatly and appropriately, and repainting or finishing.

Consider other features. A door may have built-in glass lights, and these should be in good shape. And don’t overlook the obvious – things such as old mail slots.

You can find these materials online, but first check with your local retailer. Show them this article. Maybe they will stock these things if they know you want them, and it’s good to support your local businesses.

Next time we’ll talk about windows.

Dave Keefe is a fifth-generation Vermonter who has worked for over 35 years as a contractor, consultant and teacher to improve the performance of existing homes.

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