Autumn is just around the corner, which means it is time to start getting your house ready for winter. When was the last time you checked your attic insulation?
We all know that keeping your home comfy and cozy throughout the long winters can be costly. This cost is growing each year due to constantly increasing energy costs and more frequent extreme weather occurrences.
Upgrading your attic insulation is one of the easiest ways to reduce your heating costs. Proper attic insulation can reduce your heating bills by 20% - 50% and create more consistent temperatures throughout your home.
Because heat rises, attics can account for as much as 30% of our heat loss. This is typically due to inadequate attic insulation and gaps around pipes, vents, electrical wires and especially electrical fixtures like pot lights.
Since attics often account for such a large percentage of our heat loss, upgrading your attic insulation is the quickest and easiest way to reduce your home’s heat loss, usually only requiring a weekend to complete. And, since upgrading your attic insulation does not usually require a large investment, it is the most cost efficient place to start preparing your home for winter.
Many homeowners put little thought into their attic insulation. They believe that their home was built by a reliable builder, and they are confident that the insulation was done properly. However, even if everything was done perfectly when the home was built, you should still be looking into upgrading your attic insulation.
Firstly, the effectiveness or R-values of most insulation materials decrease over time with some losing as much as 25% of its original R-value. Batt insulation and blown-in cellulose insulation, which are the most types of insulation used in attics, can settle over time. As it settles, less air is trapped within its cells, reducing its effectiveness. Excess moisture can also reduce the R-value of some insulations.
Secondly, the recommended and required R-values have changed significantly over the years. In 2009, most building codes for Northern climates required an R-40 attic insulation with most builders only complying with the minimum requirements. Today, most building codes have been increased to require an R-50 minimum attic insulation with most homebuilders upgrading that to R-61.
In other words, if you own a 10 year old home, your energy lose through your attic could be as much as 50% greater compared to a new home. Thus, your energy bills could be as much as 50% higher.
There are many different types of insulation. However, most houses built today have unfinished attics spaces in which the insulation sits directly above the ceiling of the upper floor. Batt insulation or blown-in cellulose insulation is most commonly used in these applications because there is no limitations to how thick the insulation is; it tends to be more cost efficient, and you can do it yourself if you are so inclined.
If you have an accessible attic, which is often used for storage, you will need to use a different type of insulation which allows you to achieve your desired R-value within the 2 x 8 floor joists or stop using your attic for storage.
If your attic space is conditioned (heated and cooled) then you will need to insulate within your roof joists. Urethane spray-foam insulation is now most commonly used in this application, although other options are available.
Whether you are planning on insulating your attic yourself or hiring a professional, it is a good idea that you go into this project with some basic knowledge on the different types of insulation available to you and the codes related to them. Remember, some contractors will try to sell you what they want you to buy rather than what is best for you and your home.
When upgrading your attic insulation it is important to ensure your attic is properly vented. Attic ventilation and attic insulation are closely connected. Proper ventilation will allow your insulation to work more effectively, lower your heating / cooling costs and ensuring your home is healthy.
There has been so much information devoted to attic ventilation that one would think it is a complicated topic. Actually, the approach to attic ventilation is so clear and simple that it should be hard to screw up. Yet many homes have been built without the proper attic ventilation, which is surprising considering providing proper attic ventilation adds very little in cost or time when building a house.
I am confident that if home builders had to pay the heating and cooling bills for the first 3 years, many things would be done with more care, including the roof ventilation.
While the intent of attic ventilation varies on the climate you live in, the approach stays the same.
In hot climates, the intent of the attic ventilation is to expel solar heated air from the attic space in order to reduce the cooling load of the building. The closer the temperature difference between the interior conditioned space and the attic space, the better results you will get from your attic insulation.
In colder climates, the intent of the attic ventilation is to maintain a cold roof temperature to avoid ice dams and expel any moisture that escapes from the interior conditioned living space into the attic space. Moisture trapped in an attic will cause wood decay and mold, as well as lower the efficiency of your insulation.
In mixed climates, your intent changes from season to season; however, the approach to ensuring good attic ventilation stays the same.
Attic ventilation is a two part process. The warm, moist air is expelled through roof vents, ridge vents and gable vents located at high points in the attic using convection currents. However, in order for the warm, moist air to be expelled from the attic, cooler air needs to be pulled into the attic to replace that air. This is the function of your soffit vents.
So, it is important that when adding or replacing insulation in your attic that you do not block the air flow coming in from the soffits. Stapling plastic or Styrofoam baffles to the roof sheathing near the eaves will prevent the insulation batts or the loose blown-in insulation from blocking the soffit vents or touching the underside of the roof.
For more information about attic ventilation read the quinju article, Attic Ventilation: Your House Cool and Dry.
Upgrading your attic insulation will not just lower your winter heating costs. It will also lower your summer cooling costs and reduce the carbon footprint we leave on the earth. Reducing our greenhouse gases will reduce global warming. We all need to do our part to reduce global warming and protect our planet.