For underfloor heating water there are three main types of underfloor heating loop configurations.  The type of configuration depends on the construction techniques and practices in different countries.

In general when pipe layout plans are being formulated, attention should be paid to routing the supply flow to the external walls or other potentially cold areas, such as windows.  At this stage, avoiding passing through expanison joints, included in the slab design, should be considered.

The temperature drop in the underfloor heating water pipe loops should be kept low, approximately 10 – 15 degree C, in order to avoid uneven floor temperature.

The series or serpentine pattern loop layout is what we use at Underfloor Heating Systems Ltd.  Pipe spacing with a boiler as a heat source can be kept at c/c 250 mm and when using a heat pump c/c 200 mm is fine.

As the temperature drop between the flow and the return loops are kept low, the series pattern will give an even floor temperature across the whole floor area.

The series pattern adapts to all kinds of floor structures.  It can be easily modified for different energy requirements by altering the pipe pitch.  It is suitable for most underfloor heating installations in dwellings.  However, a very flexible pipe is recommended, such as the HENCO multilayer pipe from Underfloor Heating Systems Ltd.

At Underfloor Heating Systems Ltd we never use the snail or spiral pattern for loop layouts.  It is more complicated for the installer to fit and we see no advantages of using the snail pattern for the underfloor heating water loop layouts.