Underfloor Heating Pipe Calculator
Metres of pipe and number of loops for an underfloor heating circuit.
Results
Pipe length
176.7
m
Number of loops
2
Length
88.3
m
Pipe length
166.7
m
What this tool does
Pipe length is simply area divided by spacing, plus the run out to the manifold and back. Loops are limited to around 100 metres for 16 mm pipe because a longer circuit needs too much pump pressure and arrives at the far end already cold — so the area gets split into several balanced loops.
Formula
length = area ÷ spacing
Variables
| Symbol | Meaning | Unit |
|---|---|---|
a | Area | m² |
sp | Pipe spacing | cm |
ld | Distance | m |
ml | Maximum loop length | m |
L | Pipe length | m |
N | Number of loops | — |
LL | Length | m |
LA | Pipe length | m |
Worked example
- Area25 m²
- Pipe spacing15 cm
- Distance5 m
- Maximum loop length100 m
- Pipe length176.7 m
- Number of loops2
- Length88.3 m
- Pipe length166.7 m
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- For work that must comply with a standard or be signed off, check the result against the applicable code and have it reviewed by a qualified engineer.