# Battle of the Boards: Celotex vs. Kingspan vs. Mannok – Which PIR Insulation is Right for You?

**By Customer Service (Next Day Insulation)** · 2026-02-04

When you’re looking to upgrade your home’s thermal efficiency, **PIR (Polyisocyanurate) insulation boards** are often the go-to choice. They are lightweight, easy to cut, and offer some of the best thermal performance per millimetre on the market.

But with big names like **Celotex, Kingspan, and Mannok** all available at [Next Day Insulations](https://nextdayinsulations.com/ "insulation next day delivery")[](https://nextdayinsulations.com/), how do you choose the right one for your project? In this guide, we break down the key differences to help you decide.

## 1\. Celotex: The Versatile All-Rounder

Celotex is perhaps the most "famous" name in UK insulation. Their GA4000 and XR4000 ranges are staples for floor, wall, and roof applications.

-   **Best For:** General purpose use in residential extensions and renovations.
    
-   **Key Advantage:** Incredible availability and a wide range of thicknesses (from 12mm up to 200mm).
    
-   **Thermal Conductivity:** Typically **0.022 W/mK**, which is the industry standard for high-performance PIR.
    

## 2\. Kingspan: The Premium Specialist

Kingspan is often seen as the "premium" choice, particularly their **Kooltherm** and **Therma** ranges. While often slightly higher in price, they offer specialized solutions for specific builds.

-   **Best For:** High-spec projects where space is at a premium or specific building regs (like fire or acoustic performance) are strict.
    
-   **Key Advantage:** Their **K100** series can offer thermal conductivity as low as **0.018 - 0.021 W/mK**, meaning you can use a thinner board to achieve the same U-value as competitors.
    
-   **Niche Products:** They offer dedicated boards for pitched roofs (TP10) and cavity walls (TW50).
    

## 3\. Mannok: The Value Powerhouse

Formerly known as Quinn Therm, Mannok has rapidly become a favorite for builders looking for professional quality without the "brand name" markup.

-   **Best For:** Large-scale projects, new builds, and budget-conscious DIYers.
    
-   **Key Advantage:** Excellent cost-to-performance ratio. Mannok PIR boards match the thermal conductivity of Celotex (**0.022 W/mK**) but often come in at a more competitive price point per sheet.
    
-   **Reliability:** They are fully certified and widely accepted by building inspectors across the UK.
    

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## Comparison Table: At a Glance

**Feature**

**Celotex (GA4000/XR4000)**

**Kingspan (Therma/K-Series)**

**Mannok (PIR)**

**Thermal Conductivity**

0.022 W/mK

0.018 - 0.022 W/mK

0.022 W/mK

**Typical Use**

Universal (Floors/Walls/Roofs)

High-spec / Thin profiles

General Construction

**Price Point**

Mid-Range

Premium

Budget-Friendly

**Ease of Install**

Excellent

Excellent

Excellent

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## Which Should You Choose?

-   **Choose Celotex if…** You want a reliable, tried-and-tested board that is easy to find and meets all standard UK building regulations.
    
-   **Choose Kingspan if…** You have very limited space (e.g., a thin wall or narrow rafters) and need the absolute lowest thermal conductivity possible to meet your U-value targets.
    
-   **Choose Mannok if…** You are insulating a large area and want the best possible value for money without sacrificing thermal performance.
    

## Get It Delivered Tomorrow

No matter which brand you choose, the most important part of any build is keeping it on schedule.

At **Next Day Insulations**, we stock a massive range of [PIR Insulation Boards](https://nextdayinsulations.com/collections/pir-insulation-boards "next day delivery pir insulation boards") from all these leading brands. With our reliable delivery, you can get your materials on-site exactly when you need them.

[**Browse our full range of Insulation Boards**](https://nextdayinsulations.com/collections/plasterboards "Next day delivery plasterboards")

**Tags:** Celotex, comparison, insulation, Kingspan, Mannok

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> Source: [Next Day Insulation](https://nextdayinsulations.com/blogs/smart-advice/battle-of-the-boards-celotex-vs-kingspan-vs-mannok-which-pir-insulation-is-right-for-you)