4. Heat Loss - floors.

Another factor to be aware of is the varying rate of heat loss from the floor at ground level. The illustration at right shows the situation with a solid concrete floor. Here most heat loss occurs around the perimeter, while further in the heat has progressively more concrete to travel through before it can escape.
XXA raised timber floor shows a different pattern of heat loss since the air circulates beneath it and can reach all exposed surfaces. Raised floors generally lose more heat than solid concrete floors but modern insulating materials are doing much to minimise the difference.
XXThis degree of detail is somewhat 'over the top' when you are simply chosing a stove for a single room. But for larger projects it does become important to take all factors into account. Otherwise small errors become big ones and you risk ending up with a heating system over or under specified for the job.