Choosing The Right Insulation Level for Overhead Sectional Doors

Overhead sectional doors play an important role in warehouses and loading bays.

They are used day in and day out - sometimes dozens of times per shift. They occupy large openings that connect the facility to the outside world.

For this reason, they have a direct impact on operational efficiency.

But whilst many buyers focus on size, operation or safety, insulation is often overlooked. Yet sectional doors can significantly influence energy consumption, internal working conditions and long-term running costs.

Here’s what you need to know about door insulation levels, and how you choose the right one.

WHY IT MATTERS

Building insulation is about managing energy consumption and internal temperature stability.

Warehouses and loading bays typically contain large open spaces that are expensive to heat or cool.

Frequent door openings can therefore lead to rapid temperature loss. If you are operating doors without appropriate insulation, energy is continually escaping - and that becomes both a cost issue and a sustainability concern.

Heat loss commonly occurs through:

• Poorly insulated door panels
• Gaps around seals and thresholds
• Slow opening and closing cycles

For this reason, selecting a door system with the correct insulation specification is not simply a technical decision, it is an operational one.

INSULATION LEVELS

Most industrial sectional overhead doors use insulated sandwich panels filled with foam insulation. The difference lies in panel thickness and overall construction.

Across the industry, common insulation levels include:

40MM INSULATED PANELS:

This is typically considered a standard insulated specification for sectional doors in general warehousing environments.

A 40mm panel provides reliable thermal performance for buildings where temperature control is important but not critical. For many distribution centres, this offers a balanced solution between cost and performance.

Examples within the Stertil Thermadoor range include the 640C insulated door for general industrial applications and the 640D door designed specifically for loading bay environments.

80MM HIGH-PERFORMANCE PANELS

For higher-performance applications, 80mm insulated panels provide significantly improved thermal performance.

This is particularly relevant for:

• Temperature-controlled storage
• Food production environments
• Pharmaceutical facilities
• Buildings targeting higher EPC ratings

The Stertil Thermadoor 680D door delivers one of the highest insulation values available in the market, helping to reduce heat transfer and improve internal climate stability.

But it’s not just about thickness.

DESIGN, SEALS AND CONSTRUCTION

Whilst thicker panels generally improve insulation performance, other design features play an equally important role.

Energy efficiency is also influenced by:

• High-quality perimeter seals
• Effective bottom seals
• Minimising air leakage around guides and joints

Stertil offers an enhanced ISO package that increases the overall insulation U-Value of its Thermadoors by up to 25%.

This is achieved through additional track insulation, along with thermally optimised top and bottom profiles and insulated end caps.

In other words, insulation performance depends on the complete door system - not just the panel core.

SPEED

Every second a door remains open allows heated or cooled air to escape.

In high-traffic loading bays, this effect is amplified. Doors may open continuously throughout the day, and cumulative heat loss can be significant.

Some sectional overhead doors, such as the Stertil Thermadoor Sprint door, can close up to five times faster than conventional models.

Reduced open times mean:

• Less conditioned air escaping
• Reduced strain on HVAC systems
• Improved internal temperature stability
• Lower overall energy usage

A fast overhead door allows you to combine the robustness of traditional sectional doors with the efficiency associated with high-speed doors.

CONSIDERATIONS WHEN SPECIFYING

Selecting the correct insulated sectional door depends on your operational environment.

Before specifying a door, consider:

• What internal temperature must be maintained?
• How frequently will the door operate?
• Is the building exposed to wind or harsh weather?
• What are the long-term energy cost implications?
• Are you prioritising upfront cost or lifecycle value?

A standard 40mm insulated door may be entirely appropriate for general warehousing.

However, for temperature-sensitive operations, an 80mm high-performance door could deliver long-term savings that outweigh the initial investment.

For this reason, insulation should always form part of the early design discussion - not an afterthought.

READY TO REDUCE HEAT LOSS?

Not all overhead sectional doors deliver the same insulation performance. Panel thickness, sealing quality and operational speed all play a role.

If you would like guidance on selecting the right insulated sectional door for your warehouse or loading bay, the Stertil Dock team can help.

Contact Stertil on 08707 700471, or email info@stertil.co.uk.