The hidden value in insulation specification
The energy market disruption that began earlier this year has resulted in higher gas and electricity prices for many customers. Here, Thomas Merton, Technical Manager at Armacell, looks at what heating engineers can do to help their customers tackle some of these increases.
Many homeowners, especially those coming off fixed-term contracts, are already feeling the impact of higher energy bills. For installers, this is an opportunity to help them with energy efficiency improvements, both in new and retrofit scenarios. High-performance insulation for pipework, specifically closed-cell polyethylene (PE) foams deliver meaningful reductions in energy consumed.
Why pipework insulation matters more when energy is expensive
Uninsulated or poorly insulated pipework is a persistent source of energy waste. In normal times, this inefficiency is often overlooked. When energy prices are elevated, as they are now, every unnecessary kilowatt hour carries a heavier penalty for homeowners.
Closed-cell insulation addresses this directly. Unlike open-cell or fibrous materials, it has inherently low vapour permeability and excellent thermal resistance, making it highly effective at minimising heat loss. Its lightweight, flexible polyethylene foam structure allows it to be easily formed around corners and obstacles, making it ideal for retrofitting in confined areas like airing cupboards, lofts and other hard-to-reach places.
Selecting the right insulation material
The choice of insulation material has a significant bearing on long-term performance. The low thermal conductivity of PE foams like Tubolit DG provides high thermal resistance in a relatively compact wall thickness — important where space around pipework is limited, as is common in retrofit situations.
Closed-cell PE foams also provide intrinsic resistance to water vapour diffusion. When moisture migrates through some insulation materials as a heating system cycles on and off, it eventually reaches cooler pipe surfaces. When it does this the moisture condenses, and progressively wets the insulation from the inside out. This significantly reduces thermal performance and can cause pipe and bracket corrosion.
Because of this, fibrous insulation materials require a separate vapour barrier to achieve comparable protection, and any breach of that barrier creates a point of vulnerability. Closed-cell PE foams avoid this risk entirely, maintaining their physical properties over a wide temperature range and resisting the mechanical stress of thermal cycling.
Getting insulation thickness right
Specifying the correct insulation thickness is critical to maximising performance and is an area where installers can add real value. Underspecification is a common and costly mistake; thicker is not always proportionally better, but too little insulation is always a problem.
The relationship between pipe diameter and insulation thickness is important. Smaller diameter pipes have a higher surface-area-to-volume ratio and benefit significantly from relatively modest increases in thickness. For larger diameter pipework, the incremental gains from additional thickness are smaller.
As a general rule, pipes up to 15mm diameter should carry a minimum of 19mm wall thickness of closed-cell foam insulation. Pipes between 22mm and 54mm, used in individual dwellings, benefit from 25–30mm as a practical minimum. For non-domestic and multi-residential projects, the thicknesses required for areas outside the dwelling are larger. Here, a higher fire performance is required where the use of ArmaFlex would be recommended.
In practice, optimal thickness should be calculated using the pipe operating temperature, the ambient design temperature and the thermal conductivity of the insulation material.
Our technical resources and specification tools can assist with this calculation across the full Tubolit product range.
The way forward
In the current energy market, conversations with customers about insulation upgrades are easier than they have been for years. Energy costs are visibly elevated, the causes are widely understood, and the prospect of prolonged price pressure is clear. For installers, this makes energy efficiency upgrades a straightforward and compelling proposition to customers.
