Good questions will often have short answers and long answers. “How does insulation affect my energy costs?” is a good question.
Here’s the short answer: proper insulation has the effect of lowering your energy costs. You might even say that there’s a direct correlation between insulation and energy costs – the more insulation a building has, the lower its energy costs will be.
Short answers are problematic, however, because while they can point you in the right direction, they don’t give you the why behind the what. That’s why we’re dedicating this entire article to explaining how roof and wall insulation affect a building’s energy consumption. Let’s dive in.
What Is Insulation?
Thermal insulation exists to stop heat transfer. Heat always moves toward cold spaces – insulation impedes this movement. That means that insulation keeps buildings warm in the winter by making it more difficult for heat to move from the warm interior toward the cold exterior. In the summer, insulation keeps buildings cooler by keeping warm exterior air away from the building’s cooler interior.
Why is roof and wall insulation important?
All forms of building insulation are important – your doors, windows, and even your floors all impact how heat moves into, through, and out of your building. Your roof and walls will be particularly important points for insulation, however.
The roof is likely the largest surface area of your building. It’s constantly exposed to solar radiation, an important source of heat. Heat moves up, which also means an improperly insulated roof can lead to heat quickly seeping out of your home.
Your building’s walls are, of course, another large surface that can be affected by the sun’s radiation, as well as both conduction and convection. In other words, your roof and walls are both big surfaces – and the bigger the surface, the more important it is to insulate.
Climate & Energy Efficiency
Insulation will help you save on energy costs in any climate – but the types of roof and wall insulation you’ll choose will vary from climate to climate. Climates that are extremely cold benefit more from high levels of insulation. In fact, every region has its own recommended R-values, a measurement of the thermal resistance of insulating materials. In colder regions, higher R-values are recommended.
In warm climates, insulation can still lower the costs of air conditioning, and relatively high R-values are still recommended. These climates are particularly well suited to alternative methods of preventing heat gain – radiant barriers that reflect the sun’s rays, for example, can seriously reduce the heat gain of buildings in hot climates.
All this to say, the best insulation for commercial roofs in northern Canada will differ substantially from the best insulation for residential roofs in southern Texas. Your climate, and how your building is used, will dictate the type and amount of insulation you’ll need.
Over-insulating Your Roof & Walls
You’d be forgiven for thinking over-insulating is a bad idea. It sounds like it means “using too much insulation”, but what it actually means is “insulating your building above and beyond industry standards”.
By over-insulating, you can almost completely eliminate heat transfer in your building. That means your building will stay at room temperature year-round. In mild climates, you may not even need to use heating or cooling equipment, and you’ll be well served by heat pumps – you may not need a furnace or boiler.
Not needing to use an air conditioner or a furnace will seriously lower your building’s energy costs – heating and cooling are by far the greatest contributors to the energy bills of a building, as well as to its ongoing carbon emissions. But over-insulating your roof and walls does impede air transfer.
To counteract that, we recommend using energy recovery ventilators if you plan on over-insulating. These ventilators will ensure that your building is supplied with fresh air, all while allowing your insulation to stop unwanted heat transfer.
Other Techniques To Lower Energy Costs
Insulating your roof and walls is an important piece of the puzzle when it comes to lowering your building’s energy costs. There are a number of other things you can do to reduce your energy costs even more.
Opt to use energy-efficient heating and cooling equipment instead of standard furnaces and air conditioners. Heat pumps are usually an excellent idea in mild climates, and in warm climates. You can also replace your central air conditioner with a ductless air conditioner.
Energy monitoring techniques can also help reduce your building’s energy consumption. The right thermostat can help you improve energy efficiency by helping you monitor how much energy you save by changing the temperature in your building by a degree or two. These thermostats can also enable you to alter the temperature based on the occupancy of the building and the time of day. You can even adjust the temperature using your smartphone with some thermostats.
Heating and cooling make up most of a building’s energy costs. Properly insulating your roof and walls, coupled with other energy-saving techniques, can seriously reduce your overhead costs.