The ThermoSphere Foil Kit is the all-in-one complete set for wood, laminate, carpet and vinyl floors — the 140W/m² ThermoSphere Foil combined with 5mm cushioning underlay and 2mm acoustic cushioning overlay in a single box. Total floor build-up of just ~9mm. The underlay and overlay together provide 19dB impact sound insulation — valuable in flats and multi-storey buildings. The only foil system compliant with Section 753 of the 18th Edition Wiring Regulations. Lifetime warranty on registration.
140W/m²
Output
~9mm
Total Build-Up
19dB
Sound Insulation
Section 753
18th Ed.
IP68
Protection
Lifetime
Warranty
Key Features
Complete Kit — Foil, Underlay and Overlay in One Box
Everything for a compliant floating-floor heating installation: 140W/m² ThermoSphere Foil, 5mm cushioning underlay and 2mm cushioning acoustic overlay — more cost-effective than buying each component separately.
Foil + underlay + overlayCost-effective
19 dB Impact Sound Insulation — Ideal for Flats and Apartments
The 5mm underlay + 2mm overlay combination provides 19dB impact sound insulation. Significantly reduces footstep noise to the floor below — essential in flats, apartments and multi-occupancy buildings.
19dB sound insulationIdeal for flats
~9mm Total Build-Up — Minimal Height Impact
Foil 1.5mm + underlay 5mm + overlay 2mm = approximately 8–9mm total build-up — among the lowest for any complete floating-floor heating kit. Practical for retrofits where door clearances and floor transitions are critical.
~9mm build-upRetrofit friendly
Section 753 Compliant — The Only Foil System That Is
The only foil system in the UK fully compliant with Section 753 of BS 7671 (18th Edition) straight out of the box.
Section 75318th Edition
Continuous Earth Braid and Accessible Cable Loops
The same unique continuous protective earth braid and accessible cable loops as the standalone foil — the safest and easiest foil system to install.
Earth braidAccessible loops
Lifetime Warranty — Stays with the Property
Backed by a lifetime warranty when registered online. Uniquely, the warranty transfers with the property on sale — the new owners remain covered.
Lifetime warrantyProperty warranty
Technical Specifications
Technical Data — Foil
Voltage
230V / 50Hz
Output
140 W/m²
Foil Thickness
1.5mm
Width
500mm (heated width 450mm)
Max Floor Surface Temperature
29°C (limited by thermostat controls)
Protection Rating
IP68
Wiring Compliance
Section 753 of BS 7671 (18th Edition)
Technical Data — Underlay and Overlay
Underlay
5mm cushioning underlay
Overlay
2mm cushioning acoustic overlay
Total Build-Up (kit)
~8–9mm
Sound Insulation
19dB impact (underlay + overlay combination)
Warranty
Warranty
Lifetime (online registration required)
Country of Origin
United Kingdom
ℹ Installation: All electrical connections must be made by a qualified electrician in accordance with BS 7671. Register your product with ThermoSphere online to activate your lifetime warranty.
Frequently Asked Questions
What floor finishes can I use this kit under?
Engineered timber, solid wood, laminate, LVT, vinyl and carpet. Max timber board 18mm. For carpet, total tog (carpet + HDF overlay) must not exceed 2.5 tog.
Does this include a thermostat?
No — thermostat sold separately. Choose the T-MO for Wi-Fi/app control.
Is the overlay in the kit the same as an HDF overlay board?
No. The kit includes a 2mm cushioning overlay. For carpet installations an HDF overlay board is also required above the 2mm overlay. See the ThermoSphere foil installation guide.
Can I cut the heating cable?
Never cut the cable. Cut only the foil at cable loop points to turn corners.
How do I calculate area needed?
Measure total floor area and subtract fixed furniture footprints (beds, wardrobes, kitchen units). Select the kit size to match the heated area.
Related Products
ThermoSphere Foil (heater only)
Foil only — for use with existing or alternative layers
ThermoSphere T-MO Thermostat
Smart Wi-Fi/BLE thermostat
ThermoSphere Programmable Thermostat
Standard programmable thermostat
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
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