Ducting Insulation And Its Effect On Your H&V System

HVAC stands for Heating, Ventilation and Air Conditioning. In the UK, it is likely referred to as the H&V system. If the centralised Air Handling Unit is considered the lungs of a building, then its veins and arteries are the interconnecting networks of ducts.

Ductwork serves as the primary means of air circulation for a building, and only when it is installed and insulated properly, can it reduce heat loss and prevent a variety of other issues.

Every building has a unique set-up of an H&V system. The importance of ducting insulation, valve jacket insulation and H&V insulation in general, is more pronounced in commercial and industrial settings. However, they are also important at home. 

More often than not, we tend to concentrate on loft insulation and insulating walls and floors and forget about pipe insulation and duct insulation, which is not ideal, especially if we are looking for ways to cut down our energy expenses with today's record energy prices.

In this article, we will be discussing duct insulation. The different materials used to insulate ducts, cost of duct insulation, installing duct insulation and its effect on H&V systems.

Why is Duct Insulation Important?

Thermal insulation is necessary for H&V ductwork and systems to maintain the intended air temperature and function. Meaning to say, that without proper ducting insulation, your ductwork will not be able to deliver the conditioned air you've paid to produce. 

Heat or cooling will be lost, which means, the system will have to work extra hard to maintain comfortable indoors. This usually converts to higher energy bills and loss of money. Duct insulation prevents these unwanted losses and saves both money and energy.

Duct insulation is also necessary to keep residents of a building safe and comfortable. According to building regulations, proper duct fire protection is essential to preventing a hidden fire from spreading throughout ductwork, especially those connected to kitchen extract fans. 

Using duct boards like Rockwool FirePro can ensure extended protection in case of fire. Rockwool FirePro can provide up to two hours of passive fire protection for square and rectangular-shaped ventilation and smoke extract ducts.  

The soundproofing properties Isover Climcover duct wrap, ensure acoustic comfort for building occupants. Fibreglass duct insulation dampens unwanted noise from mechanical systems leading to quieter indoors and more efficient workspaces. It can be used on normal ductwork but also on acoustic ducts too.

What problems can ducting insulation help avoid?

When the cool air moves to the warmer regions of the house or heated air travel via ducts to the colder areas of a building, moisture accumulates inside or on the duct system leading to condensation, also known as duct sweating. 

The moisture can then cause a variety of issues, including moulds or water pools gathering on the floor, leading to slips or accidents. It can also damage ceilings and walls from the water pooling on top of plasterboards and the like.

Duct insulation can stop moisture from forming in your ductwork. For example: If you are looking to insulate ductwork that travels through unheated rooms and voids like loft spaces or garages. This can be done by applying a duct wrap about 25mm thick and has a K value of less than 0.04W/m K like Isover Climcover Duct wraps

Therefore, for both financial and environmental reasons, it is critical that you insulate ventilating ducts. 

What are the different materials used to insulate ducts?

Generally, duct lagging materials are usually made from either rock wool or fibreglass. We also store Kingspan duct insulation,who manufacture PIR and Phenolic duct insulation called thermaduct boards. 

Buy Insulation Online supply Thermaduct boards and phenolic foam boards for ductwork at industry-leading prices.

There are many factors that will influence your decision on which duct insulation material to choose, the main ones being money, temperature, acoustic insulation requirements and moisture content of the air in the duct and the surrounding area. 

Ducting Insulation usually comes in two forms: 

Duct Wrap: Duct insulation wrap, or ductwrap as it's mostly known, is made of fibreglass or rock wool with aluminium foil-facings on one side. Duct wraps usually have a low thermal conductivity or K-value of 0.034 - 0.037 W/mK. 

They can be used to insulate both ventilation ducts of any shape. Ductwrap cost around £5/sq.ft and are available in 25mm, 40mm and 50mm thicknesses. At Buy insulation online, we store Isover Climcover and Rockwool ductwrap.

Duct Boards: Duct board is commonly manufactured in 40mm and 50mm thicknesses. They are boards made of rock wool with foil-facings on one side and can be used to insulate exterior and interior ductwork. 

Duct board insulation costs around £8 per sq.m. They are primarily used to insulate rectangular and square-shaped ductworks. At Buy Insulation Online, we stock Rockwool duct boards.

As mentioned earlier, some duct boards are made of PIR or phenolic foam. They are again ideal to insulate rectangular and square-shaped ductwork. They are costlier compared to mineral wool duct boards, priced at around £12 per sq.m and more difficult to install properly. 

Kingspan duct insulation boards also offer hardly any acoustic insulation properties but they make up for that with their superior thermal insulation. In comparison with Rockwool ductwrap, for instance, they enable the installer to use nearly half the thickness of the Rockwool ductwrap

Nitrile Rubber Insulation: These insulation sheets are made of foamed nitrile rubber. They are lightweight and quite easy to install on all ducts of all shapes. Nitrile rubber insulation performs extremely well at temperatures as high as +85°C as low as -165°C.

They also come with an in-built vapour barrier, that prevents condensation and duct sweating. It is pricey compared to duct boards or duct wraps. Buy Insulation Online store nitrile insulation sheets from the world leading K-Flex brand. 

So it depends on the application and what is important to the occupiers when selecting the right insulation. At Buy Insulation Online, we offer our customers free advice from our decades of experience in the duct insulation industry to allow them to choose the right ducting insulation for them.

How does Duct Insulation work?

Fibreglass or mineral wool used in the duct wraps and duct insulation boards has millions of tiny air pockets between their strands. These air pockets contain the heat from the ducts and do not let them pass through easily. 

In short, they form a protective covering around the ducts and prevent heat loss. Usually the thicker the barrier is, the more effective the thermal insulation it gives.

Ducts can be insulated using two types of foam insulation boards - PIR and Phenolic Foam.

Kingspan Thermaduct is basically PIR insulation for ductwork. PIR is a polymeric substance produced by mixing polyols and isocyanates. The blowing agent used produces millions of tiny, intact, unconnected bubbles that trap gas within the fabric of the rigid board insulation. The gas trapped in these bubbles is one of the most thermally effective insulating materials, as it allows very minimal passage of heat through the fabric of the PIR board.

Similar to PIR, phenolic foam is also closed-cell insulation. To make a phenolic foam board, high pressure is applied to plastic foam(phenolic resins) in the presence of a surface-activating agent and Pentane as a blowing agent. Like PIR, it is closed-cell insulation that has millions of small cells containing gas. Closed-cell insulation does not let heat pass through its fabric easily. 

Where do you need Ducting Insulation? 

It is better to insulate all heating and cooling ducts to prevent heat loss or heat gain and prevent duct sweating. When it concerns insulating other ventilation ducts, extra care must be taken. We can separate the ductwork into two zones for better understanding. 

Internal ductwork: Ducts that carry conditioned air across the building can be insulated by using foil-faced fibreglass insulation rolls like Isover Climcover or Rockwool ductwrap

Duct wrap can also be used to insulate ducts in cold spaces like crawl spaces or loft spaces.

Its also a good idea to insulate fresh air ductwork, that is ductwork that pulls air directly from outside. This will stop any duct sweating from occurring.

If the ductwork is at low level in an internal area where it may get damaged, it will need an additional protective layer of insulation cladding such as aluminium stucco cladding or Ventureclad like materials such as Klasseclad.

External Ductwork: Ducts that are situated outside will be constantly exposed to the elements. They must be insulated with water-resistant nitrile rubber sheets like K-Flex or Armacell. You can use ductwrap in conjunction with a weatherproofing solution such as aluminium stucco cladding or 5 ply laminate such as Ventureclad or Klasseclad.

What is the cost of insulating Ductwork?

The cost of installing duct insulation greatly depends on the type and thickness of the insulation you need. The cost of duct insulation also depends on the complexity of the duct system. 

Obviously, the larger the building, the more complex the duct system is. More area needs to be covered, thus increasing the cost of installation. The most common locations where ducts need to be insulated are the loft and crawlspaces, so the contractors probably need a duck between the floor and the ceiling. 

The installation cost also depends on the convenience of access to your ducts, and the cost of labour in your area.

Is Duct Insulation a DIY task?

You can insulate duct insulation yourself, but only if you are a competent DIYer. You can also refer to our detailed blog on installing duct insulation. 

We, however, recommend contacting thermal insulation contractors for the job. Why? Because though the installation is rather simple, the task is labour-intensive. 

You will need to access difficult-to-reach spots in your building. It can also be very uncomfortable wearing all the necessary PPE to protect you from the itching side effects of the fibres given off by the duct insulation.

So, it is definitely better to hire professional insulation contractors for the job if you can afford it. 

How to improve the energy efficiency of the H&V system? 

To make your building more energy-efficient and for the UK to achieve its carbon neutrality goal, it is an absolute must that every building in the UK has an efficient H&V system in place. 

Ductwrap and duct insulation boards may be durable, but if the duct itself is damaged or punctured, no amount of insulation can help with the heat loss. So, it is important to periodically check the H&V system. 

Regular H&V system maintenance, especially if your H&V equipment is used frequently, is a very effective strategy to maintain optimum energy consumption. Professional contractors usually undertake maintenance works and they can help you with these.  

If a part of the H&V system is giving you problems, then it is better to retrofit only that section or duct of the system than replace the entire network. If some parts of your HVAC system are functioning flawlessly, but others are wasting energy, this can be a good fix. 

Retrofitting is generally a smart option if you have kept your HVAC system in good condition over the years because many of the components will still be functional.

In Conclusion.

The performance of the H&V system of any building needs is optimised with regular checks, proper maintenance and insulation. 

Ducts need to be installed correctly and insulated with ductwrap or duct boards, properly. Only then can any building become truly energy-efficient.

Buy Insulation Online can help you make your H&V system efficient by providing top-quality duct wrap, duct insulation boards, valve covers and pipe lagging at low cost. 

Additionally, we also supply insulation boards like PIR, XPS, EPS, insulated plasterboards, loft insulation rolls, insulation batts for soundproofing and much more. 

We only sell quality insulation products, plus with every order, we will plant one tree for free and save five trees on the Amazon. Feel and do good whilst you shop with us and make a donation when you buy insulation.


Your feedback is greatly appreciated, please comment on our content below

Your email address will not be published

Required fields are marked *

Cookies help us deliver our services. By using this website, you agree with our use of cookies. Learn more