Loose Wire Underfloor Heating Overview. For rooms that are small, awkward and have a lot of permanent fixtures to work around, loose wire underfloor heating is the best method. The loose wires allow you to arrange your heating system as you see fit and offer more flexibility than pre-spaced mats that work best in very uniform rooms. It’s more time consuming to fit but is suitable for use with almost all floor types and can even be waterproofed for bathrooms. Loose wire is futureproof so if you want to change your floor covering further down the line, you won’t need to refit your underfloor heating.