8 Ways to Improve Energy Efficiency in Your Building Envelope Design

An energy-efficient building envelope refers to an effective boundary between the conditioned interior of the building and environment beyond it.

This boundary includes:

  1. The heat-resistant materials in the façade of the building.
  2. Highly insulated windows and window seals.
  3. Effective vapor control and vapor barriers that keep moisture out.
  4. Airflow controls that protect against uncontrolled drafts.

An effective building envelope will lower the cost of fuels and power that control interior climates, and will improve the level of comfort as well as the health and safety of tenants within the building.

If all buildings implemented various energy-efficiency measures, electric bills would be 10 per cent lower by 2035. Simple changes, like switching out your current light bulbs with new LED light bulbs or installing insulation panels, dynamic windows, and photovoltaic modules integrated into the building’s structure, are good ways to contribute to an energy-efficient building envelope design.

Focus on improving these elements for building envelope energy efficiency


Avoid thermal bridging

When designing your building envelope to be efficient, strive to avoid thermal bridging. Thermal bridging occurs when structural elements conduct heat through the insulation.

Image from Fine Homebuilding.


Thermal bridging can lower your insulation’s R-value by 50 per cent. Avoid this by making sure the insulation isn’t being significantly compressed, and that there’s an uninterrupted area of rigid insulation located in the cold side of the wall assembly.

Ensure Air Tightness 

Leaky windows, walls, ductwork, doors, louvers, and roofs not only allow heat to escape and cold to come in, but they can allow condensation to form in the building envelope, which can lead to mold growth.



A continuous air barrier will help maintain the interior temperature, thus ensuring that the occupant is comfortable. Additionally, installing heat recovery ventilation systems can safeguard building occupant health while simultaneously recapturing 50 per cent or more of exhausted air energy. Ideally, the supply of fresh outside air should only be via the building’s ventilation system.

Understand Your HVAC System 

HVAC equipment needs to be sized for the maximum load, or it can consume more energy than necessary 95 to 99 per cent of the time. This can affect almost 30 per cent of a building’s total electricity consumption. To minimize this, implement a variable frequency drive in your HVAC system.


The results can be startling, reducing system pump and fan speed by half can result in lowering energy use by 90 per cent.

Invest in Smart Control Lighting


Smart control lighting can affect 25 per cent of the building’s total electric consumption. Daylight and occupancy lighting sensors are necessary for an energy-efficient building.

Thermostats and Occupancy Sensors 

Linking thermostats with occupancy sensors can greatly reduce temperature control-related energy consumption. Automatically raising or lowering temperatures during preset hours is inefficient since occupants don’t always use every room in the building during the same hours each day.


Linking occupancy sensors with room thermostats saves money by ensuring unoccupied rooms aren’t needlessly being heated or cooled. Additionally, it helps ensure that occupants experience comfortable temperatures wherever they are in the building at any time.



Ensure your energy-efficient building envelope allows for daylighting. According to the U.S. Department of Energy, 80 per cent of lighting-related energy costs can be reduced by using daylighting. This can be achieved by designing high-efficiency skylights into your building envelope.

South-facing Windows 

Design your building envelope with ample south-facing windows. These windows passively absorb heat from the facing sun during the winter.

building under the sun

These windows also need to be fit with a system of shading to keep the building cool during the summer. Proper window design can reduce temperature control-related energy consumption by 85 per cent.

Be Aware of New Energy-Efficient Technologies 

Finally, always keep current on new technologies. For example, large-area fluidic windows are being developed to “reduce embodied energy and CO2 to 0 for window surfaces after four months of usage.”

They work by using “a fluid contained in micro-channels to harvest ambient heat and solar energy and manage heat exchange, thereby boosting energy efficiency.” They are projected to lower total energy consumption by 10 per cent for the complete longevity of a building.

Learn more about energy-efficient building design from the DELTA® Academy