Draft guards are a cheap and effective way of cutting down heat losses from your home. Drafts can account for as much as 30% of the cost of your heating bill - that is a vast waste of both energy and money when added up over a winter, especially when cheap and easy solutions exist to eliminate the most common causes of drafts
At its simplest a draft excluder is a fabric barrier that blocks gaps under doors. Ill fitting doors and windows are some of the commonest sources of cold air infiltration into a building as they play up to natural air convection currents (cold air sinks so passes beneath doors).
Traditional draft excluders are just cloth 'sausages' filled with relatively heavy wadding - when placed snugly in front of doors they do a good job of cutting drafts down. Unfortunately they are easy to dislodge, especially when a door is in regular use, and only need to be knocked a few inches out of place to loose their effectiveness. And if you have ever tried to keep one in place behind a door as you leave a room you'll have an idea of their inadequacies.
A simple improvement is to use a draft guard that moves with the door, but doesn't impede it's opening or closing. Some types permanently fasten to the bottom of the door itself and act like a brush, sweeping the floor. Others fit beneath the door and slide with it as it moves. Here are some that I have looked at - just be aware that they are not all suitable for every situation.
These are a neat way of overcoming the "draft excluder keep becoming dislodged" problem. Simply, they have a sausage of foam either side of the door, with a fabric sheath that passes beneath.
They have some weaknesses:
Personally I really like these - they are cheap and easy to install and, come summer, you can take them off again.
This new variant has just become available, so I haven't actually tested it myself yet. Initial review on amazon look good though.
Basically it clips to the bottom of the door on one side only and sweeps across the floor as the door moves. It is supposed to overcome some of the short comings of the twin version above, as it will work against a door jam, and glides over uneven surfaces and door mats.
This is a "no tools" installation and easily reversible when summer comes along.
With some time and ingenuity you can cobble together quite an effective draft excluder, similar to the "twin draft guard" above.
What we did was use some large size tubigrip and stuff it loosely with balled up newspaper. By sliding it under the length of the door, and carefully adjusting the paper so that it is evenly spread on both sides, you get a cheap and effective wind block that moves with the door.
It isn't really as good as the commercial ones (the newspaper tends to shift around a bit) but if you don't mind adjusting it fairly regularly it does a reasonable job. This worked well for us last year because our interior doors are very wide, so off the shelf products don't fit well.
While many modern homes have very tight construction, older building can be very leaky and let air infiltrate through many different nooks and crannies. While it is very difficult to block all of these off completely, you can help minimise their effect by shutting interior doors and installing draft proofing in door ways.
Wood stove actually can make leaky buildings worse, because the chimney is continually drawing air from the house, through the fire and out to the atmosphere. Air is sucked into the house from outside to replace it, finding it's way through all the cracks.
The first thing to work out is if drafts are actually a problem in your building. This is a little process you can use to work out which doors to focus on:
You will probably find that some rooms have stronger drafts coming from them than others. Make these a priority and get draft excluders fitted to the door quickly. Follow up by trying to find the leak into the room from outside; this might be a poorly fitting window, an external door or a ventilation gap that needs closing. Deal with this and you will save money, fuel AND your house will feel warmer.