Our house was built, as far as we can tell, in 1970. That means it's not nearly as drafty as a really old house, and much better insulated, but it has had over 40 years for bits of the house to settle and leave gaps that can let the winter in. So after Brian finished dealing with the rain barrel last weekend, he turned his attention to weather-stripping our two main entrances to keep the cold at bay.
Last time we applied weather-stripping, we used foam tape (the cheap stuff), and as it turns out, we probably applied it wrong. The instructions in my trusty home maintenance manual say the place to put it is along the inside edge of the doorstop, so when the door, the foam compresses to form a nice, tight seal. However, as you can see in this picture of the front door, we actually pressed it up against the side of the doorstop. It still helps block out drafts that might come whistling through the gaps, but it doesn't actually fill the gaps.
Now, on the front door, the foam tape had actually held up fairly well, despite our little goof in applying it. But on the side door, where we used a narrower strip, the adhesive backing on the foam had gradually lost its stickiness, letting the foam peel up and away from the door jamb. Largish chunks of the foam were missing altogether, leaving gaps in the doorframe were big enough to let ants into the house all summer long. So rather than just buy another roll of the foam tape, we decided to try something that looked like it might hold up a bit better: a felt strip that attaches with nails or staples.
Well, it turns out that this stuff doesn't go in the same place as the foam tape—not the place where it's supposed to go, nor the place where we put it. Instead, according to the picture on the package, it's supposed to be nailed directly to the inside of the door jamb, where it will press up against the edge of the door when it's closed. Brian did this on the side door, but he couldn't do it on the front, since it would interfere with the door hardware.
However, there was still quite a bit of felt left, so he figured he might as well try to apply some on the inside edge of the doorstop, the place where you're actually supposed to put the foam tape. The felt was too wide for this narrow surface, but he just cut it lengthwise and stapled it in place. One narrow half-strip covered two edges of the doorstop on the side door, and he still had the other half left over to do the front door.
This experiment was a success, more or less. Both doors are now very snug indeed—so snug, in fact, that it takes a good hard slam to get them to close. Before, you could just push the door into place, and it would stay put; now you really have to throw your weight against it to make sure that it catches and stays caught. With the side door, it's usually obvious if I haven't managed to get it closed fully, because the added thickness of the felt against the door jamb pushes the door back open again. The front door, however, occasionally looks like it's fully closed, but isn't actually secure. Once or twice, I've failed to notice it until it starts to get dark and the light of the setting sun shining through the gaps in the doorframe. So I've now gotten into the habit of relying on my ears rather than my eyes; even if the door looks shut, I don't assume it is until I hear the click of the latch in its groove.
These newly tight-fitting doors will take a little adjusting to, but it may get easier over time as the felt compresses. In the meanwhile, it's worth a little extra effort to dodge those drafts. It probably won't make a bit difference on our gas bill, but it'll keep us a bit cozier through the long winter months.
UPDATE (11/18/14): The felt weather-stripping on the front door proved to be unworkable. After I accidentally left the door not-quite-shut for the third time, Brian removed it and instead installed a different kind that we picked up at the same time: a simple plastic strip, folded lengthwise. When you close the door, the fold automatically closes up enough to let the door stay shut, but stays open just enough to fill the gap. This stuff may not provide quite as tight a seal as the felt, but it's definitely better than a partly open door.
He also used the same stuff to jury-rig a fix for the bottom sweep on our storm door, which had partly crumbled away with age. The ideal solution would have been to replace the whole sweep, but we weren't sure we'd be able to find one the right size for our particular storm door (which is likely original to the house and may not even be made anymore). So Brian cut a piece of the V-shaped weather stripping to size and slipped it into the gap, and while it may not provide a perfect seal, it blocks out most of the wind and insects.