Why should you insulate your home?

Regardless of where you live in South Africa, we all have to contend with varying and sometimes extreme weather conditions, with Cape Town being no exception! With a reputation for hosting four different seasons in one day, regardless of what time of the year it is, our city is known for having some crazy cold and wet days in the winter, and even more unpleasant windy days in the summer—not to mention that our summers are extending well into the winter calendar, and vice versa.

When weather conditions become increasingly volatile and swing from one extreme to another, what is the best way to keep a comfortable temperature in your home? While using air conditioners and heaters guarantees a quick solution, who can afford to pay inflated Eskom prices these days?

We spend the majority of our lives indoor, why is it then that we feel the winter cold more than Americans and Europeans? How did we end up literally paying for harsher indoor seasons? More importantly, how can we stop paying for them while enjoying more comfortable homes?

The answer: improved home insulation as a result of South Africa’s epidemic of inadequate (or non-existent) home insulation.

So, why is insulation so important for your home?

While home insulation is almost universal in America and Europe, South African homeowners are often surprised to learn that a well-insulated home is the key to lower electricity bills, and that their home is poorly insulated in the first place    .

winter heat loss summer heat gains








Fortunately, improving your home’s insulation is simpler and more affordable than most people think. In fact, the typical home recoups the insulation costs within 5-6 years, in the form of 40-50% lower heating and cooling bills.

Now who would not like to keep their home comfortable all year round and save at the same time?

What is home Insulation?

Left to themselves, houses don’t trap much heat or cold inside them. In fact, quite a significant amount of heat can easily escape through your walls, ceilings, and windows in winter - or, conversely, enter your home in summer.

A regular home loses on average. 

  • 35% of its energy through the ceiling
  • 25% through the walls (depending on the type of construction)
  • 20% through the floors
  • 10% through the windows
  • 10% via Air gaps.

Insulation prevents this by slowing down heat loss in winter and heat gains though:

  1. Bulk Insulation (thick layers of dense materials that trap air inside your home)
  2. Foil Insulation (reflective layers that bounce heat back to its source)

Both methods slow down your home’s transfer of heat so that you don’t have to use heaters or air conditioners as much (and when you do, you don’t need to run them as long) to maintain a comfortable indoor temperature. In this way, insulation acts as a blanket for your home.

How does insulation work?

To understand how insulation works it helps to understand heat flow, which involves three basic mechanisms:

  • Conduction: Is the way heat moves through materials.
  • Convection: Is the way heat circulates through liquids and gases, and is why lighter, warmer air rises, and cooler, denser air sinks in your home.
  • Radiation: Radiant heat travels in a straight line and heats anything solid in its path that absorbs its energy.

Insulation works by counteracting air’s natural tendency to move from warm areas towards colder areas,  by reducing the transfer of heat.  This means that during the winter months, insulation prevents cold air from coming into your home through the ceilings or walls. By reducing heat flow, insulation helps keep the living spaces in your home cooler in summer and warmer in winter, reducing the need for artificial heating and cooling.

Insulation used in buildings works as a barrier to hinder the movement of heat in or out of the living areas. This makes well insulated buildings more energy efficient, making them cheaper to run which is also good for the environment.


An insulating material’s resistance to conductive heat flow is measured or rated in terms of its thermal resistance or R-value -- the higher the R-value, the greater the insulating effectiveness. The R-value depends on the type of insulation, its thickness, and its density.

Installing more insulation in your home increases the R-value and the resistance to heat flow. In general, increased insulation thickness will proportionally increase the R-value.

 What are the benefits of home insulation?

Compared to the same home without insulation, a properly insulated home result in:

  • 70% less energy needed for heating and cooling (and thus a decreased carbon footprint)
  • 40-50% reduction of average annual heating + cooling costs
  • Up to 10 degrees cooler home in summer
  • Greater Comfort; warmer, cosier home in winter
  • Full payback in 5-6 years
  • Improved respiratory health
  • Lower energy bills
  • Reduced reliance on aircon and heating units
  • Improve the value of your home
  • Prevents moisture condensations
  • Fire resistance and Fire protection
  • Acoustic benefits
  • Environmentally friendly

Where Can You Install Insulation?

When it comes to installing insulation, it can be done in probably more place than you think.

In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, floors over unheated garages or porches, knee walls, and in between interior walls, as well as ceilings and floors.

The goal is to create a consistent wrap around the home, a “thermal envelope,” with no penetrations.

Generally speaking, it is done in three key areas of your property.

  • Underfloor Insulation

A surprising amount of air can escape through your floors, a well-insulated underfloor greatly contributes to the thermal efficiency of your home.

  • Wall Insulation

Wall insulation is the process of inserting insulating materials between layers of brick or timber that make up a wall.

  • Ceiling Insulation

Ceiling insulation creates a heat flow barrier between your roof tiles and ceiling boards, by preventing heat from passing through whether it from the sun on your roof or from the inside of your room.

In summary

The bottom line is Insulation is a cost-effective and energy-saving way to insulate your home.

Whether you are renovating, building, or replacing your old insulation, there is an appropriate insulation option for your needs. Consider what you need, where you are located, and what type of insulation would suit you best.

Consult with a professional builder or installer before doing any insulation installations in your home.