The insulation requirements for floor constructions on upper floors, over heated space below, are met entirely by JUPITER’s 30 mm thick heating panel range.

Part-L of building regulations stipulates U-values that a ground floor, or a floor over unheated space must achieve, dependent upon whether the work being undertaken is considered a refurbishment, extension, or new build. To meet these requirements, an additional layer of insulation is normally required below the underfloor heating system.

Loading Capacity

For most domestic projects Kingspan K103 is the best performing primary insulation with a thermal conductivity of only 0.019 W / mK. Kingspan Kooltherm K103 has also proven to be strong and stable for use in residential and light commercial applications. The combination of our Ideal EPS heating panel and was successfully tested for loading capacity at our laboratory in Germany.

High Strength

The insulation used should have a minimum compressive strength rating of 120 kPa. Insulation with this compressive strength is suitable for thicknesses of up to 100 mm under the JUPITER Ideal system range. It is recommended that only one layer of insulation is used. Do not make up heights using multiple layers. If greater depth of insulation is required, a higher compressive strength product such as Kingspan GreenGuard should be used instead.

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K103 U-Value Calculator

To assist in estimating the depth of Kingspan K103 required for your project we have produced the below tool.

For refurbishment works a U-value of 0.25 m² K / W should be achieved. Extension floors should achieve a stricter U-value of 0.22 m² K / W whilst new build projects should halve this figure to 0.11 m² K / W.

The Perimeter / Area ratio is obtained by dividing the exposed perimeter by the total floor area. Exposed perimeter refers to only the walls that connect the heated internal air to an unheated space, be it the outside world or an unheated garage

The smaller the Perimeter / Area Ratio figure the smaller the amount of insulation that is required, for example, a large area with a small exposed perimeter will have smaller heat losses and, therefore, will require less insulation. If you would like Kingspan to provide you with an official document confirming the thickness of insulation required for your building project contact Kingspan on 01544 387 382 or email