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How much is too much insulation?

Heating and cooling accounts for up to 50% to 70% of the energy used in an average home. Installing insulation in your house is the most practical and cost-effective way of making your home more energy efficient, keeping it warmer in winter and cooler in summer and can save up to 50% on your energy bill. In addition, insulation can also reduce condensation in your home and some types of insulation can make your home more soundproof. A well-insulated house is very energy efficient and will need very little additional heating and cooling.

Insulation helps to:

  • save money on your energy bills
  • reduce your energy use and lower greenhouse gas emissions
  • reduce reliance on heating and cooling systems
  • improves your comfort at home.

The most important part of a house to insulate are the walls which typically lose about 30% to 40% of heat, the roof comes in second with about 25% heat loss, then windows and doors with 20% and finally the floor.heat-loss

How much money you will save by insulating your home depends on many different factors like the size of your house and the type of insulation used. In addition, if your house is old you will probably have to add more insulation.

How insulation works

Naturally air flows from a warm area to a cooler one. Insulation works by limiting air movement and the still air inside the insulation helps to prevent heat from escaping. Insulation is rated in terms of thermal resistance (R-Values) – the higher the R-Value the better it is.

There are two main types of insulationfoil-insulation

Bulk insulation acts as a barrier to heat flow between your house and the outside, keeping heat out in the summer and in your home in the winter. It comes in rolls, boards and batts and can be made of glass wool, polyester, natural wool or recycled paper.

Reflective insulation is usually used in houses in hot climates and deflects radiant heat. It’s usually shiny aluminium foil laminated onto paper or plastic.

Some insulation products are available that combine the features of bulk and reflective insulation.

The type of insulation that is best for your home depends on whether you need to keep heat in or out, or both. The design of your house, the materials it is made from and the orientation are also factors to consider.

How much insulation should I use?thermal-insulation-in-walls

It’s not really possible to over-insulate a building, so the easy answer to this question is as much as possible! However as there is a point of diminishing returns the best bet is to aim for the “sweet spot” where the insulation is efficient and the cost is within your budget.

There are some benefits to over-insulating as over time almost all cellulose and fibre glass insulation decreases in R-Ratings as it settles.

Make sure it’s installed properlyroof-insulation

It is very important to make sure your insulation is installed by experienced, competent professionals. Insulation that has gaps, gets wet or is crammed in too tight will not protect your home. Don’t forget to insulate the hot water pipes and geysers!

Find a reliable contractor here

If you are considering investing in solar panels, heat pumps or any other green source of energy for your home the first step you should take is to improve your home’s insulation. Skipping this step means that you will spend a lot of money on an expensive system to cover the energy demands of you home.

Who is Claire Cardwell?

Claire Cardwell of Blue Designs is an architectural designer with over 15 years experience in the Johannesburg area. She has worked on small projects – double garages, swimming pools – and new houses from a 1,300m² house in Featherbrooke Estate, to houses of only 110m² in size. In 2015/2016 she worked on a small complex, a warehouse, a nursery school and new houses in the Waterfall Country Estate, Copperleaf Estate, and in Limpopo on an old-age home and frail care facility in North Riding.



David A Steynberg, managing editor and director of HomeTimes, has more than 10 years of experience as both a journalist and editor, having headed up Business Day’s HomeFront supplement, SAPOA’s range of four printed titles, digimags Asset in Africa and the South African Planning Institute’s official title, Planning Africa, as well as B2B titles, Building Africa and Water, Sewage & Effluent magazines. He began his career at Farmer’s Weekly magazine before moving on to People Magazine where he was awarded two Excellence Awards for Best Real Life feature as well as Writer of the Year runner-up. He is also a past fellow of the International Women’s Media Foundation.

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