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Electric Underfloor Heating Systems: In-Slab Heating / Concrete Heating

The in-slab heating cable is designed for installation in concrete slabs to provide gentle background warmth in areas where heat is required for long periods. The slower heat-up time and cool-down time of the inslab cable makes it particularly suitable for rooms which are in constant use.

An electric heating element is installed after the reinforcing mesh has been added and prior to the concrete being poured. Warmup's in-slab elements are designed for installation within the concrete slab. The element wire is tied to the reinforcing mesh of the concrete floor prior to it being poured. The elements consist of fixed length earth-screened electric heating cables of large diameter (approximately 6.2mm) with factory-fitted cold tails for connection to supply. The heating wire is encased in a tough insulation, is then covered with metal braiding — providing an electrical earth and added protection. A super tough PVC outer shield then provides further insulation and protection. The result is a super tough element capable of withstanding the rigours of a typical concrete pour. The resistance wires are factory terminated in a waterproof joint assembly to the supply conductor and earth conductor of the cold tails respectively.

Typical design wattage is 150 watts per square metre. The cable spacing can be varied from between 150mm and 300mm depending upon requirements but is typically around 180mm. All installations should be protected by a RCD (Residual Current Device). The site electrician is required on site during the concrete pour to ensure that no damage to the heating elements occurs.

Key Features
  • Even heat distribution throughout the room
  • Provides individual control per room and the flexibility to install heating in all or only selected rooms in a home
  • All features completely hidden — no visible part
  • 10 year warranty
  • Backed by an established New Zealand company
  • 100% safe RCD protected
  • Doesn't dry out air, recommended for allergy sufferers
Scope of Use
  • Can be used in residential (private and terraced houses) and commercial properties — e.g. apartments, aged care facilities, and hotels
  • In-slab heating consists of an electric heating element positioned within the concrete slab
  • Ideally suited for heating polished or coloured concrete floors, or when using heating in conjunction with particular types flooring such as wood, carpet, vinyl or tile
  • In-slab heating can be installed in selected rooms, all of which allow individual control
  • Ideal for new homes and extensions
  • Recommended for allergy sufferers
Limitations on Use
  • In-slab heating is not suitable for providing rapid response heating — rather its ideal use is in providing gentle background warmth by heating up the whole concrete slab
  • The site electrician is required on site during the concrete pour to ensure that no damage to the heating elements occurs
Other Performance Attributes
  • Proper installation and correct control and operation will ensure economical use —especially if used in conjunction with off peak power
  • Silent and odour-free heating system
  • Doesn’t dry out the air
  • Recommended for people with asthma and allergies


  • 10 year warranty on heating elements
Supplier Declaration of Conformity


Inslab Preparation
Product Information

Warmup is an international company providing quality electric underfloor heating solutions to homes and businesses worldwide.

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