History of Insulation
For as far back as history goes, the earth has experienced four distinct seasons. Some areas have always experienced more extremes in terms of temperatures and therefore had to find ways to maintain a comfortable living environment. Insulation has been used throughout the centuries to keep heat in and cold out or vice versa.
Ancient Forms of Insulation
Prehistoric people built shelters to protect themselves from the elements, originally using organic materials and later more durable substitutes. Hot climates would construct homes with thick walls that would insulate against the heat and provide a cooler and more temperate indoor environment in which to live.
• Ancient Mayan ruins in Central America;
• Egyptians also used these construction methods to keep out the desert heat of the Sahara. These homes had low roofs and small windows so the heat couldn’t easily enter and remain in the homes.
• Ancient Greeks probably made some of the more significant discoveries in terms of insulation they used cavity walling to insulate the buildings. Cavity walling has a gap between two walls which traps air and moderates the temperatures. During the hot summer months, cavity walls kept the warm air out and in the cooler winter months, it would help keep the warmth inside the homes.
• The Romans also used cavity walls, though in addition, they used materials such as cork to insulate hot water pipes so the heat from the pipes would not transfer to the surrounding walls and floors, causing them to crack. Fabrics were also used as additional insulation. Scraps of cloth would be tucked into window frames to keep out the desert dusk or the icy European cold. Rugs made from animal furs were used as carpets and thick linen drapes were used as curtains. Elaborate tapestries were hung on walls and helped to manage some of the moisture buildup in the stone buildings. The tapestries also helped moderate the draughts that could sometimes cause an added chill.
Industrial Types of Insulation
During the Industrial Revolution, insulation became an integral part of many designs. Steam power was driven by coalburning furnaces and asbestos was the main type of insulation used because of its flameresistant properties. Interestingly enough, asbestos had been used by the ancient Greeks and Romans as insulation and they had dressed their slaves in it. Even though the Greeks had noted that it seemed to cause lung disease in those who were exposed to it, the industrialists seemed oblivious to this fact. For more than a century, asbestos continued to be the main form of insulation. It was only in the mid1970s that the harmful effects of asbestos were finally properly documented which caused industries to consider other forms of insulation. Fiberglass batting was then widely used in building and construction projects and is still used today.
The Need for Energy Efficiency
In recent decades, there has been an increasing awareness to become more energy efficient and environmentally conscious. Insulation requirements are becoming more detailed and stringent. The thinking is that better the insulation, the more energy efficient the building. Everyone knows that insulating your home is one of the single most useful things you can do to help you start saving energy. Between lagging your pipes, looking after your loft and insulating your walls, there’s hundreds of pounds – and tonnes of carbon – to be saved.
Facts
There are lots of performance facts bandied about, especially over how much you can save by installing proper insulation in your wall cavities or loft (around £120 and £150 a year respectively, in case you didn’t already know) but here are a few of the more unusual ones:
- Swedish builders put three layers of insulation in lofts, each 100mm thick and separated by a layer of building paper. It improves the insulation effect by around 60% when the wind blows,since it traps air within the insulation and stops it from being forced out.
- According to some estimates, as much as a quarter of the heat lost through the fabric of a typical house occurs as a result of cold bridging – losses around uninsulated areas such as where the walls meet the floors or roof, and around windows and external doors.
- Around 270300mm is the optimum depth for loft insulation; doubling the depth beyond this will not double the energy saving.
- Squashed loft insulation 50% less effective (NPL, 2013).270mm performance = 6.11 m2.K/W , when compressed to 100mm =3.09 m2.K/W
If every house in the UK was fully draughtproofed, the nation
would save enough energy to easily heat all the homes in Belfast and Cardiff combined!
Making Comparisons & Things you need to know
Comparing different kinds of insulation and building materials to try to see which one will be best for your needs can sometimes seem a bewildering problem. Here are a few straightforward facts to help you:
- A good insulator is a bad conductor of heat; it’s blindingly obvious when you think about it, but it’s worth saying all the same!
- An insulator’s K-value is one of the ways commonly used to measure its “thermal conductivity.” It’s all about how much heat can travel through a piece of insulating material onemetre thick for every one degree C difference between outside and inside temperatures.
- U-values are typically used to give an idea of the flow of heat energy through a whole building component – a wall, window or roof – rather than a single type of insulating material. The measure the amount of heat moving through the whole thing for every one square metre of its surface area.
- For both K and U-values, the lower the number, the better insulation you’ll get.
- A good insulating material should have a K-value no higher than 0.041 W/m.k
- A wellinsulated outer wall should have a U-value of less than 0.2 W/m2.K and a window 1.0 W/m2.K or lower.