How ceiling insulation impacts energy efficiency

2020-09-19T12:03:13+00:00September 19th, 2020|Features|

By Eamonn Ryan

Insulation is both integral to energy efficiency and part of the SANS 10400-XA regulations. Insulating a ceiling dramatically slows down heat loss or gain, thus reducing the need for heaters or air-conditioners, which translates directly to less energy used and lower energy bills.

Fitting ThinkPink Aerolite insulation. Image credit: Saint-Gobain

Fitting ThinkPink Aerolite insulation. Image credit: Saint-Gobain

Affordable home layouts are evolving to cater more for individuals whose lifestyles centre on family, work and entertainment, as shown as one of the important trends identified in this month’s project, Westview 2 Security Estate (see page 17). More families are opting for open plan homes where light and views across living areas are free flowing.

While this is conducive to contemporary living, it can also affect comfort especially in colder months as cool air flows freely throughout the open space. At least 35% of the average home’s energy is lost or gained through the ceiling in a typically non-insulated home. With ever-increasing power costs, energy efficiency legislation for new buildings SANS 10400-XA was published by the National Regulator for Compulsory Standards in 2011.

The best time to implement energy saving and insulation to a home is at the time of construction. However, when it comes to appearances versus living comfort, and during retrofitting projects, architects are notoriously blind to the needs of insulation, which is required by standards. SANS 10400-XA governs alternative sources of heat, but also requires all new buildings to comply with performance parameters. This means that insulation will have to be installed to achieve the stipulated R-value – for which purpose South Africa has been divided into six climatic zones according to humidity and temperature variations.

Ultimately, energy performance certificates will have to be issued (as per an amendment in 2014). This regulation points to the direction in which home building is heading – but it is not being uniformly enforced by building inspectors. Thermguard owner, Eric Quarmby, says he regularly sees new homes signed off by an inspector with no insulation (notwithstanding its provision in the building plans) whereas in other regions they would not be signed off. He also sees plans for 50mm insulation when the SANS climatic requirement may be for 135mm, and he has also been asked to quote for insulation barely one third of the regulated thickness.

However, Jolene Blundell, Product Manager for Saint-Gobain Isover, manufacturers of ThinkPink Aerolite, says the company has seen “better compliance” with new homes being built with insulation, as required by SANS 10400-XA. “We encourage homeowners to take active measures by inspecting their ceiling and ensuring there is in fact ceiling insulation and that the insulation is of the required thickness, then plan their ceiling renovation accordingly. To aid homeowners and home-installers with identifying their insulation requirements, we have developed a free online calculator to try simplify the process.”

Quarmby adds: “Meeting that R-value can involve other building materials, so we are not in a position to see the full picture. You’d have thought that since 2011 all buildings would have insulation – but I get new homeowners regularly calling me for help with their freezing homes. Insulation of the entire building envelope is common in countries such as the UK and US, where 70% of homes are built with timber – and insulation of wood is a lot easier – while in South Africa homes are not built or designed with insulation in mind, and are also seldom made from wood.” If they were, our homes would use less energy.

He says the ‘deemed to satisfy’ rule allows engineers to have sharply different interpretations of what satisfies the SANS 10400-XA. “All architects should be designing homes with SANS 10400-XA in mind, but based on what we see, we know they are not doing so where it might detract from the home’s appearance.”

An advantage of timber-built homes is that “a wooden house can be factory-built and delivered on site much quicker, but it’s not in our mindset. A US- or UK-built timber house uses far less energy to heat and cool than South Africa’s brick houses.”

Factory manager Scott Quarmby says in retrofitted homes insulation’s payback time is 18 months to two years in reduced utility bills (depending on how frequently heaters are used). “Our SABS-approved Thermguard will prevent up to 91% of the heat generated in the home from escaping upwards through the ceiling in winter and will keep 88% of summer heat out as well (according to SABS tests).” Thermguard is made from 80% recycled newsprint in a low energy process.

“Insulation can be built into walls at the time of construction and that is quite common abroad, but typically is used in South Africa almost exclusively in ceilings. You can insulate an entire house, including beneath floorboards or between floors.” The application process is done by blowing the newsprint particles onto the ceiling boards and between the rafters, thereby getting into every crack and cranny to completely stop the movement of air and heat.

Scott (left) and Eric Quarmby, Thermguard factory manager and owner, respectively. Image credit: Eamonn Ryan

Scott (left) and Eric Quarmby, Thermguard factory manager and owner, respectively. Image credit: Eamonn Ryan

It’s the same concept whereby homeless people scrunch rolled up newsprint under their clothes to insulate themselves while sleeping during freezing winters.

“The beauty of our system is that there is no need for measuring and cutting to size, making it ideal for use in roof areas with limited space. It is extremely quick and requires only one person in the ceiling space, thereby reducing the potential for damage,” says Eric Quarmby. With regard to high-end as well as affordable housing, Scott Quarmby says the product suits insulating walls in steel or wood frame homes, which are becoming more popular, but not traditional brick homes.

Eric Quarmby suggests that insulation is trending in the direction of lessening its environmental impact, in common with all construction materials. It takes approximately 10 to 14 times less electricity to make cellulose fibre compared to other insulation, cellulose having the additional benefit of being made from recycled newsprint and is also from renewable and sustainable sources (trees).

Additives such as boric acid and magnesium sulphate are added to the recycled shredded newsprint to make the product fire retardant and insect and rodent resistant.

Ceiling insulation: the easy route to fight climate change

Jolene Blundell, Product Manager for Saint-Gobain Isover, manufacturers of ThinkPink Aerolite also tested to SABS standards, says: “ThinkPink Aerolite Insulation performs to the same extent as Thermguard Insulation, which has shown to reduce 91% of the heat transfer lost through ceilings and walls. That is, of the 35% of heat escaping through the roof in winter, 31.5% of the heat can be retained and only 3.5% heat is ultimately lost in winter or gained in summer through the roof. There is a payback period of two years for a typical household ceiling area of 150m2. The same would apply for walls where one could expect a heat loss or gain of 25%; with insulation in the walls, there would only be 2.5% heat loss or gain through walls.”

“When it comes to appearances versus living comfort, and during retrofitting projects, architects are notoriously blind to the needs of insulation.”

Wall cavity insulation for both internal walls and drywall partitions also provides the added benefit of acoustic insulation between rooms. Thanks to its exceptional acoustic insulation properties, insulation reduces the levels of noise from outside and absorbs and insulates noise from the inside. “When we are acoustically comfortable, we are happier, more productive, and experience fewer health issues. However, this is not common practice in South Africa. Due to cavity insulation being legislated abroad, it is also more widely accepted to use blown in glasswool in both ceilings and walls, installed in a similar way cellulose insulation is applied. Blown in glasswool involves using both newly-produced and scrap insulation to minimise waste to landfill. The product is suited to both internal and external cavities in steel, wood and traditional brick frame homes.

The Isover family of glasswool products. Saint-Gobain

The Isover family of glasswool products. Saint-Gobain

Blundell also reminds us that “Geysers make up about 35% of the electricity use of a household – with potential savings that can be attained depending on the surface area of exposed pipe that can be insulated the geyser thermostat settings and the hot water usage. Just by insulating the pipes, you save up to 37% of the heat used by the geyser system with a payback period of six months. By Insulating both the geyser and the pipes, homeowners can save up to 58% of the energy used by their geyser. This offers a payback within four to six months,” says Blundell.

The Department of Social Housing has ambitions to ensure all 40-45 m2 homes are equipped with ceilings and insulation in order to comply with the energy efficiency regulations. Saint-Gobain Gyproc and Isover has a ‘combi-pack solution’ specifically tailored to government and contractors as it is an all-in-one product offering, combining systems and products. The system comprises of Gypframe N concealed ceiling grid, Gyproc Rhinoboard 6.4mm and Aerolite ThinkPink 135mm or 100mm insulation. As a result, only one supplier is involved and material sourcing and logistics are simplified. The project kicked off at the start of 2015 and by 2016, this system was used in  7 000 housing units in Gauteng  alone. The rollout to other provinces began towards the end of 2016.

Blundell describes that what differentiates an insulation product is its ability to perform over the lifetime of the building once installed correctly. High Performance insulation like ThinkPink Aerolite is non-combustible, which means the glass wool does not fuel fire or propagate flames. It has the ability to return to its manufactured thickness once unpacked and installed, and maintains its thickness over the product’s lifespan. ThinkPink Aerolite has exceptional thermal resistance due to the inherent material properties and the fiberising technology used in manufacturing the product, where liquid glass is propelled through tiny holes by a centrifugal spinner – creating high quality fibres.

Small-scale testing facility at Thermguard. Image credit: Eamonn Ryan

Small-scale testing facility at Thermguard. Image credit: Eamonn Ryan

“Over the years we have invested in our manufacturing technology, to ensure we use less raw material but still achieve the same thermal performance for the product. Our automated rollup machine compresses the product up to eight times so that contractors can load more material in the transport vehicles, resulting in fewer transportation trips and reduced carbon emissions,” she says.

Across the EU, the use of insulation in ceilings, internal and external walls, floors and foundations is legislated and environmental performance of building products is continuously becoming more stringent. Blundell explains that in Europe, researchers are working to identify a plant-based binder that will not compromise the performance of the product and could then be adapted for warmer climates. “The binder we currently use is a by-product from petrochemical companies and is therefore already minimising waste in other supply chains. The product has exceptional sustainability credentials – once installed, the occupants require less energy to cool and heat spaces, therefore ensuring a saving of more than 100 times the energy consumed and CO2 emitted from manufacturing and transporting the insulation. The factories in which it is manufactured are CFC and HCFC-free, and it is made from 80% recycled glass, one roll of glass wool contains the equivalent of at least 10 recycled glass bottles – and our intent in future is to recycle more off-cut material from our production line back into the finished product.

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