Improving home insulation for savings and comfort: Part 1

Evaluating and increasing home insulation can save the homeowner money and improve comfort in winter and summer.

Fall is here and bringing with it cooler temperatures. You might have already turned on your furnace to take the morning chill out of your house. According to the U.S. Department of Energy, the average American spends 44 percent of the energy used in the home on heating and cooling. Most people think about insulation when it starts to get cold, but insulation can also cut down on cooling costs in summer for a double savings. 

Home insulation has become so important that having the correct amount in the correct places is not an option anymore. It is a necessity with the increasing cost of non-renewable energy. And if your home is more than 15 years old, it may be time to evaluate your insulation needs to see if there is enough. Home renovations are also a good time to consider additional insulation. 

Insulation works by providing resistance to heat flow. The more resistance there is, the lower your heating and cooling costs and makes your home more comfortable to be in.

Insulation works based on heat flow which has three basic mechanisms – conduction, convection and radiation.

  • Conduction is the way heat moves through materials. A good example of this is when you have a spoon in a hot cup of coffee and the handle heats up and warms your hand.
  • Convection is the way heat circulates through liquids and gases. This is why warm air rises and cold air sinks.
  • Radiant heat travels in straight lines and anything in its path warms up. Radiant barriers, unlike traditional insulation, are highly reflective materials that repel heat rather than absorb it so do not have an “R-value” rating. 

Heat flows from warmer to colder areas until the temperature difference is eliminated. In winter, this means that heat flows from heated rooms to unheated areas, such as attics, basements, garages. This heat flow can be through ceilings, floors or walls wherever there is a temperature difference. In summer, the heat flow is from outside to inside the home or building. Insulating your home will provide resistance to this heat flow. Most insulation materials work by slowing or eliminating any conductive - and to a lesser extent convection - heat flow. In addition to heat flow reduction, some types of insulation can act as a sound barrier, thus reducing noise between rooms and from the outside. 

An insulating material’s resistance to heat flow is measured in terms of its “R-value” or thermal resistance. The higher the R-value, the more insulating ability the material has. The R-value is determined by the type of insulation, the thickness of the insulation and its density. Installing more insulation in a home or building increases the R-value and resistance to heat flow. 

The amount of insulation needed depends on several factors: climate, type of heating/cooling system, areas of the house/building that will be insulated. 

Types of insulation available will be covered in Part Two of the series.

For more information on home insulation, see the Michigan State University Extension bulletin Home Maintenance and Improvement: Insulation. The U.S. Department of Energy has a variety of information on insulation as well.  

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