For the 99% of folks who don’t know anything about green building, the assumption is that solar panel installation is the first priority in heading toward net-zero energy. When you install solar panels, solar reduces the need for natural gas power by converting the sun’s rays to energy instead.
This is very much not the case, according to Eric Corey Freed, director of sustainability at Cannon Design. In fact, installing solar panels is probably the last thing many of his clients will wind up doing in their zero energy quest. The first, most important element in the structure to consider is…(surprise!) the insulation.
How insulation works
"The act of heating and cooling consumes between 50% to 70% of the total energy used in your building," explains Freed.
One key reason people pay so much to keep a building a consistent temperature is that insufficient insulation allows too much air from outside -- either hot or cool -- to seep inside. This is what triggers the constant need of an HVAC system to keep the interior of the building a certain temperature. The better your walls are insulated, the less the temperature fluctuates.
Quantifying insulation ability
The ability of a material to insulate is measured by what is called R-value. The higher the R-value a material has, the greater its insulating ability.
"Most of the older existing homes in this country are poorly insulated," says Freed. "There are over 50 million underinsulated homes in the United States, wasting the equivalent of about 2 million barrels of oil every day in lost energy."
Most buildings have the bare minimum: an R-13 in their walls and R-19 in their roofs. R-60 is considered a super-insulated and high-performance building. After attaining an R-value of 60, Freed will stop adding more insulation because he’s seen anything beyond that provides diminishing returns.
How to maximize energy efficiency
Cannon Design typically looks at three areas of efficiency to improve the opex for existing buildings:
- Insulation: Where can we add it? How much? (For existing walls, it requires opening them up or adding to a surface.)
- Thermal bridging: Are there components (windows, usually) conducting the outside temperature into the building?
- Heat gain: Is the sun heating the building in the winter (when we need it) and not heating the building in the summer (when we need to avoid it)?
When owners are trying to update their properties to no longer rely on natural gas energy, a consultancy such as Cannon will assess the property against the above checklist. Then, they’ll make the necessary modifications. Adding insulation is the first step. It's a simple yet effective way to reduce standard energy consumption because you need less power to counteract the exterior temperatures that seep into the interior.
Along with insulation, one of the most important things energy consultants look at is the strategic use of natural light. This includes steps like repositioning blinds and curtains strategically, to let in just enough light and heat but not too much -- and to track what's coming in with smart sensors.
Another very important component in lowering energy usage is installing a system that reacts instantaneously to changing conditions: that is, the light and heat coming in through windows, and heat and cold air coming in through the walls. Smart-sensor technology is the most effective way of doing this.
How does this look for the occupants of an office building on a sunny winter day, for example? The sun comes into the office through windows in the morning and heats the office, but only up to a certain temperature, after which point smart sensors are triggered and lower the blinds. Insulation meanwhile blocks the extra-cold outside air from entering the building and chilling the rooms.
The bottom line
Freed compares insulation to chocolate (more is always better) but you could also compare it to a coat: The more insulated the garment is, the less the wearer feels temperatures and elements like bitter cold wind. Insulation protects and stabilizes temperature and is a time-tested way to keep people comfortable without requiring additional energy to be expended.