We live in an old house that takes a bit of heating. We do have central heating but it doesn't seem to get the house warm enough. So we use a Rayburn woodburner in the kitchen and a small handmade woodburner in our living room.
This kind of heating seems to suit our purposes much better.
The only bug bear is when we answer the door and a load of that hard earned heat (collecting logs, chopping, splitting and storing) goes out the door and we get blasted with a cold breeze, usually for something unimportant.
We have a curtain on the inside of the door but once the door is open this does nothing to stop that breeze.
So I decided to make an outside barrier to the cold that only needed to be opened to admit a visitor and could be left closed to door step salesmen, pizza delivery, postmen and basically everyone that doesn't actually have to come into the house.
Hence the Submarine style Door Wind-cheater.
This device is fitted to the outside of your door frame and will cover your front door. When someone knocks the door, you can go open your front door and see who it is with no draughts. if it is someone you need to speak to you speak through the porthole, if you need to take in a parcel you can sign for it and take it in through the submarine door. If you need to let them in you un Velcro one side and let them in.
Importantly all keeping your house and you warm and cozy and draught free.
The door wind-cheater is good for all dwellings as you can make it for house, barn, boat, caravan wherever your home may be.