Question 1

What cable spacing should I choose?

Accepted Answer

15 cm is standard (150 W/m²). 12 cm suits cold rooms (bathroom, kitchen) or use as the main heat source. 20 cm works in lower-demand zones (supplementary warmth). Never go below 8 cm or the cable overheats.

Question 2

Single- or twin-conductor cable?

Accepted Answer

A twin-conductor cable connects at one end only, which makes installation simpler. A single-conductor cable must return to the start point — it's cheaper but harder to lay. For most situations, choose twin-conductor.

Question 3

Can I run the cable under furniture?

Accepted Answer

No. Under heavy furniture the cable overheats and fails. Leave a 15–20 cm gap from fixed furniture, and account for it: the actual heated area is smaller than the total room area.

Question 4

Do I need a temperature sensor?

Accepted Answer

Yes — it's a safety requirement. The sensor sits in a corrugated conduit between the cable runs. The thermostat switches the system off at the set temperature, protecting the cable from overheating.

Question 5

How much does underfloor heating cost to run?

Accepted Answer

1.5 kW × 8 h/day × 30 days at $0.07/kWh ≈ $25/month. A programmable smart thermostat saves 30–40% by heating only morning and evening. Infrared film is 10–15% more efficient than cable.

Underfloor Heating Calculator — Free Online Calculator