Trunking Guide For HVAC Installations – Brands And Sizes Available
Trunking Guide For HVAC Installations – Brands And Sizes Available
If you’re an HVAC installer or contractor aiming for seamless, professional, and durable air conditioning installations, selecting the right trunking system is crucial. The wrong choice can lead to unsightly finishes, increased noise, and costly callbacks…
This guide provides a comprehensive comparison of top trunking brands available in the UK for 2025, helping you make informed decisions that enhance installation quality and customer satisfaction.
Why Trunking Choice Matters in AC Installations
Choosing the appropriate trunking system has a direct impact on the success and longevity of your installation.
Trunking affects:
- Aesthetics: Ensures a clean, professional appearance that reassures clients and showcases expert workmanship.
- Durability: Protects pipework against UV damage, weather exposure, and physical wear over time.
- Functionality: Facilitates easier maintenance and minimises vibration and noise transfer.
- Compliance: Ensures installations meet industry standards and reduce the likelihood of regulatory or client issues.
Key Considerations When Selecting AC Trunking
- System Size: Ensure trunking dimensions suit the AC system’s pipe size and configuration.
- Installation Environment: Evaluate whether trunking is being fitted indoors or outdoors and factor in exposure to sun, rain, or debris.
- Material Quality: Always opt for UV-resistant, fire-retardant, and weatherproof materials for longevity.
- Accessory Compatibility: Choose systems that offer a wide range of matching components such as elbows, couplers, and end caps for a professional and secure fit.
Top AC Trunking Brands and Products for 2025
Inaba Denko Trunking
Inaba Denko’s Slimduct range is a go-to for professional installers needing a robust, UV-stabilised trunking system with exceptional longevity. Known for clean aesthetics and seamless fit, Slimduct is built for long-term reliability in both domestic and commercial environments.
Popular Products:
- 75mm Black Trunking – Box of 5: Ideal for slimline installs and residential wall splits with visible pipework.
- 100mm White Trunking – Box of 5: Provides high-visibility contrast in white-finished interiors or ceiling voids.
- 100mm Black Trunking Coupler: Ensures secure, rattle-free straight joins on outdoor pipe runs.
- 140mm Black Trunking – Box of 5: Designed for heavier commercial pipework with twin-line systems.
- 75mm Black Fixed Offset Bend: Simplifies awkward transitions between height levels.
- 100mm Black Ceiling Inlet Cover: Finishes trunking entry into ceiling voids or upper-floor installs cleanly.
Best for: Installers who prioritise a premium finish and want confidence in durability, UV protection, and an extensive accessory range for every fitting challenge.
Tecnosystemi Optima Trunking
Tecnosystemi’s Optima range is popular among engineers working on varied installs where rapid configuration is key. The robust build and wide bend radius fittings make this range especially suited for tight voids, corner installs, and limited wall space.
Popular Products:
- 75mm Black Trunking – Box of 5: Go-to pipe cover for indoor or sheltered external systems.
- OPTIMA CP 75mm Flat Elbow: Smooth right-angle bends behind interior AC units.
- OPTIMA CPS 75mm Jointed Elbow: Great for angled walls or multi-point adjustments.
- OPTIMA TA 75mm Corner Terminal: Clean trunking termination at wall junctions.
Best for: Installers needing adaptable ducting that still maintains a clean, sharp finish under time constraints. Excellent for domestic or compact commercial settings.
Strutfast Trunking
Strutfast trunking is engineered for large pipe volumes and challenging commercial environments. Designed with toughness in mind, it handles frequent foot traffic, weather exposure, and larger line sets with ease.
Popular Products:
- 140mm Black Trunking 2m – Box of 2: High-capacity trunking for rooftop installs or boiler rooms.
- 140mm Black Trunking Coupler: Heavy-duty coupler for long, exposed runs.
Best For:
Installers on industrial or commercial sites who need maximum protection and performance without compromising on appearance.
Trunking Accessories and Tools
Selecting the right accessories is crucial for achieving a professional and durable air conditioning installation. Below are some essential tools and components that ensure efficiency and quality in your projects:
Inaba Denko SLIMDUCT Cutter
The Inaba Denko SLIMDUCT Cutter is designed for precision and ease of use. Featuring a high-quality stainless steel blade with advanced corrosion resistance, this cutter delivers clean, debris-free cuts on Slimduct lineset covers. Its one-touch open/close mechanism enhances usability, making it an ideal choice for installers seeking accuracy and durability in their work.
75mm Black Trunking Coupler
The 75mm Black Trunking Coupler is an integral component of the Inaba Denko Slimduct system. It facilitates the seamless connection of trunking lengths, ensuring a neat and professional finish. This coupler is UV resistant and fireproof, making it suitable for both indoor and outdoor applications.
100mm Black Trunking Vertical Elbow 90°
The 100mm Black Trunking Vertical Elbow 90° allows for a 90-degree vertical change in direction of the trunking system. This component ensures that pipework is neatly routed around obstacles, maintaining the aesthetic and functional integrity of the installation. It is UV resistant, fireproof, and can be painted to match various indoor and outdoor settings.
Comparison Table: Trunking Brands at a Glance
| Brand | Product Name | Type | Size | Colour | Ideal For |
| Inaba Denko | 75mm Black Trunking – Box of 5 | Straight | 75mm | Black | Small pipework in residential installs |
| Inaba Denko | 100mm White Trunking – Box of 5 | Straight | 100mm | White | Indoor installs needing discreet finish |
| Inaba Denko | 140mm Black Trunking – Box of 5 | Straight | 140mm | Black | Larger commercial split and multi-split systems |
| Inaba Denko | 75mm Fixed Offset Bend | Bend | 75mm | Black | Tight pipe transitions in visible zones |
| Inaba Denko | 100mm Black Trunking Coupler | Coupler | 100mm | Black | Connecting long trunking runs outdoors |
| Inaba Denko | 100mm Black Ceiling Inlet Cover | Inlet Cover | 100mm | Black | Ceiling installs that require a neat pipe entry |
| Tecnosystemi | 75mm Black Trunking – Box of 5 | Straight | 75mm | Black | Versatile everyday use with split systems |
| Tecnosystemi | OPTIMA CP Flat Elbow 75mm | Flat Elbow | 75mm | Black | Wall corners or directional changes |
| Tecnosystemi | OPTIMA CPS Jointed Elbow 75mm | Jointed Elbow | 75mm | Black | Flexible or awkward angles |
| Tecnosystemi | OPTIMA TA Corner Terminal 75mm | Terminal | 75mm | Black | End-of-line coverage and pipe concealment |
| Strutfast | 140mm Trunking 2m – Box of 2 | Straight | 140mm | Black | Heavy-duty outdoor trunking for large systems |
| Strutfast | 140mm Trunking Coupler | Coupler | 140mm | Black | Connecting trunking lengths on large commercial installs |
FAQs: Air Conditioning Trunking
Can I use air conditioning trunking outdoors?
Yes, you can install trunking outdoors, but it is vital to choose trunking specifically designed for exterior conditions. Look for UV-stabilised products like the Inaba Denko Slimduct range, which are manufactured to resist sun damage, water ingress, and weather fluctuations. These are essential for preventing cracking, warping, or colour fading that might compromise performance and appearance.
What size trunking do I need for my AC system?
This depends on the number and size of pipes or cables you need to cover. For single-pipe mini splits, 75mm trunking is typically sufficient. If you’re installing a multi-split system or twin linesets, go with 100mm or 140mm options. Always measure the total bundle size and refer to the manufacturer’s guidelines to ensure the trunking has enough clearance for insulation and airflow.
Do I need matching accessories for my trunking?
Yes, using compatible accessories is critical. Proper fittings such as elbows, end caps, junctions, and clips not only ensure a secure and seamless fit, but they also improve the professional finish of your installation. Mismatched components can lead to poor seals, rattles, and even compromised performance. Stick with accessories from the same trunking brand whenever possible.
Can I paint or colour match trunking?
Most trunking is available in standard colours like white, black, or brown, but many installers choose to paint trunking to match interior or exterior décor. Always check with the manufacturer, as not all trunking plastics are paint-compatible. Use a suitable primer and UV-stable outdoor paint if applying on external runs.
How do I avoid trunking rattles or noise issues?
To prevent noise transfer, make sure trunking is correctly fixed using pipe clips or brackets at regular intervals. Avoid loose fits or overpacking trunking channels. High-quality materials like those from Inaba Denko and Tecnosystemi are engineered to minimise movement and vibration. Use flexible joints or couplers for long vertical runs to absorb minor expansion or pipe movement.