An Introduction to Etched Foil, Flexible Heaters

Technical reference 10th June 2026 By Richard Wench

In this guide we discuss the different types of flexible heaters available and compare their typical specifications, applications, and merits of each type.
If you still have a question, then please ask us via contact form or give us a call on +44(0)1865400514.Contents:1. Basic construction of flexible heaters
2. Flexible heater selection guide

Basic construction of flexible heaters

Flexible heating elements consist of an etched foil resistive heater circuit which is laminated between two layers of insulating material.

Some insulation materials and heat ranges also allow the addition of a self-adhesive layer, for ease of application.

Flexible heating foils designed and supplied by Carlton Thermal Systems Ltd are manufactured by Zoppas Industries and start with a minimum thickness of just 0.15mm.

This thin design and the flexibility of the heating elements and insulating materials allow them to be shaped to fit almost any type of equipment.

The heaters can be applied to most complex shapes, curves, or pipes without sacrificing efficiency or dependability.

Flexible heaters can generate a heat up to 350°C and provide fast heat-up and cool-down rates, ensuring uniform heat distribution at various watt densities. Heater can be supplied complete with:

Lead wires insulated with silicone, polyimide, PFA, etc.
Connectors to allow fast installation to existing wiring looms
Controls and thermal protection such as thermostats and thermal fuses
Built-in temperature sensors: thermocouples, PT100, PT1000, thermistors

Flexible Heater Selection Guide

The range of sizes and insulating materials available for flexible heaters, coupled with different operating voltages and heating capacities, makes the number of options available almost infinite.

The table below compares the general specifications available for common insulation types:

	Polyester	Silicone	Polyimide	Mica
Voltage Range	≤700 AC/DC (1 or 3-phase)	≤700 AC/DC (1 or 3-phase)	≤400 AC/DC (1 or 3-phase)	≤400 AC/DC (1 or 3-phase)
max Watt Density (controlled)	0.50 W/cm²	5.0 W/cm²	7.5 W/cm²	5.0 W/cm²
Watt Tolerance (EN 60335-1)	-10%+5%	-10%+5%	±2%	-10%+5%
min Thickness	0.30 mm	0.30 mm	0.15 mm	0.80 to 1.20 mm
Length Piece	10 to 2700 mm	10 to 2700 mm	10 to 600 mm (FEP), 10 to 2000 mm (acrylic/epoxy)	50 to 1200 mm
Length Roll	150 m	N/A	N/A	N/A
Width	10 to 600 mm	10 to 600 mm	10 to 600 mm	50 to 600 mm
max Continuous Operating Temperature	95°C	up to 250°C, 175°C adhesive	200°C (FEP), 150°C (acrylic/epoxy)	350°C
min Ambient Temp	-50°C	-50°C	-50°C	-50°C
Protection Class	up to IP65	up to IPx5	up to IP67	up to IPx4
Adhesive Option	Yes	Yes	Yes	No
RoHS	Yes	Yes	Yes	Yes
Approvals	UL, VDE	UL, VDE	UL, VDE	UL
Applications	Laboratory equipment Medical devices Railway application Health care beauty Telecommunication Catering equipment Heating and conditioning	Laboratory equipment Medical devices Health care beauty Catering equipment Automotive Chemical cleaning	Laboratory research Medical application Aerospace and defence Optical equipment	Laboratory research Medical application Food equipment