Passive Design and Active Building Strategies.
Passive Design
Strategies.
Passive strategies utilize what nature provides for free to keep buildings comfortable without the need for purchased energy.
Passive strategies are integrated into the design of a building to work with natural elements on a site (including sun and wind patterns) to provide natural heating and cooling of spaces through different seasons.
Adaptive Re-use
Adaptive Re-Use, most simply put, is changing the use of something which we no longer need to something new, which we now need—whether it be the up-cycling of old materials for a new purpose, or changing the function of an existing building—we are making the most of that which we already have, rather than sending the old stuff to landfill and manufacturing more new stuff.
Heritage Conservation
Heritage Conservation is a strong contributor to sustainable development strategies. Economically, it can promote job growth in skilled trades, increase property values, revitalize neighbourhoods and a wide array of tourism opportunities. Culturally, it acts as a point of pride and reference that can help foster awareness and confident cultural growth that respects traditions and stories of the area. Environmentally, Heritage Conservation encourages the re-use of existing building materials by extending the life of a building and its components, or rehabilitating damaged building materials.
Site-Optimization
Careful consideration of a building site will: minimize the disturbance on the land, protect current vegetation, mitigate the need for additional infrastructure, and provide opportunities for daylighting, solar heat gain, and natural shading and ventilation. It is ideal to select a site where existing community resources such as: schools, shopping, employment, entertainment, public transit routes, and existing infrastructure (roads, sidewalks, energy, sewers and water supply, and open green space) are accessible.
Passive Solar
Passive Solar design refers to the use of the sun’s energy for the heating and cooling of living spaces. In this approach, the building itself, or some element of it, takes advantage of natural properties of materials and air created by exposure to the sun. Examples include operable windows placed for optimal heat gain in winter, shading devices and solar chimneys for the summer, and thermal mass for both seasons. Solar chimneys create or reinforce the effect of hot air rising to induce air movement for cooling purposes. The resulting suction pulls cooler air into the building from lower, shaded spaces.
Thermal Mass
Thermal Mass is a property of a material’s ability to absorb, store, and release heat. Thermally-massive building materials such as concrete have a high capacity to absorb and to store excess heat, often from the sun, which is released into the occupied space when the ambient temperature falls below that of the Thermal Mass. Most materials which will absorb excess heat, will also absorb excess humidity. Thermal Mass materials passively act as temperature and humidity flywheels, reducing indoor temperature and humidity fluctuations without the consumption of energy.
Off-Grid
An Off-Grid building does not rely on the municipal water supply, sewer, natural gas, electrical power grid, or any other utility service. Instead, water can be sourced on-site through a well or from rainwater and is treated on-site with a conventional septic system, composting toilets, or a constructed wetland. For electricity, it is generated on-site by solar photovoltaics or wind turbines. Winter heating and summer cooling and ventilation are best augmented by passive strategies to suit the seasons (for example good thermal insulation to reduce heating energy demand and natural and night ventilation for hot summers).
Deep Overhangs
Proper window shading will allow optimal solar heat gain in the winter, while limiting unwanted solar heat gain during the summer. A correctly sized roof overhang will completely shade a window at solar noon on July 21st, when the sun is at it's highest.
Natural Cross-Ventilation
Natural Cross-Ventilation occurs when air enters a building through openings such as windows and doors on one side, and exits on the opposite side. It is driven horizontally by positive pressure on the windward side and negative pressure on the leeward side of the building, as well as vertically through the building via stack effect. Natural Cross-Ventilation reduces energy-consumption from air conditioning and ventilation units during summer months. Buildings are ideally designed to encourage Natural Cross-Ventilation through their relationship with prevailing breeze patterns.
High Albedo Roofing
High albedo roofing materials reflect sunlight and limits the amount of heat absorbed by the roof to reduce unwanted heating of attic and top floor spaces. A light-coloured roof can help decrease cooling loads during the summer, meaning lower cooling costs and a more comfortable indoor environment. High albedo roofing is more durable and longer-lasting than dark, low albedo roofing, and plays a major role in reducing the urban heat island effect.
Recycled Materials
Recycled Materials are building materials that have been salvaged from the end-of-life of one project to be given a new life on a current project.
Exterior Materials
Selecting durable and natural exterior cladding materials and treatments to withstand weathering and to extend the building’s lifespan. Upon the end of their required use such materials will ideally be returned to the biosphere with positive, rather than adverse, effect.
Green Roof
Green Roof (also known as Living Roof) systems refer to the partial or complete covering of a building’s roof with well-selected vegetation planted in a suitable growing medium spread out over root barrier and drainage layers, installed over the roof’s waterproofing membrane. Automated irrigation systems can also be integrated for ease of maintenance. Green Roofs contribute to the reduction of urban heat island effect, storm water retention, rainwater filtration, roof membrane protection, and to keeping a building cool through evapotranspiration.
Above-Code Insulation
Many energy consultants now recommend that cold-climate buildings include R-60 insulation in ceilings, R-40 in above-grade walls, R-20 in basement walls, and R-10 below and surrounding the perimeter of basement slabs—well above minimum building code requirements. We prefer to avoid styrofoam and other poly-based insulation products whenever possible, opting instead for fire-resistant, non-toxic, mineral wool insulation.
Air-Tightness
Air-Tightness is defined as the resistance to inward or outward air leakage through unintentional leakage points in the building envelope (cracks, holes, etc.). An airtight building, when combined with an appropriate ventilation strategy will result in lower heating and cooling demands, prevent mold and rot trapped in cavities and a more comfortable indoor space due to fewer drafts. It is measured in Air Changes per Hour (ACH), which is determined by performing a Blower-Door Test, which measures the amount of air flowing through "leakage points" in the building envelope at a specific pressure (50 Pascals).
High-Efficiency Windows
High-Efficiency Windows include properly installed, air-sealed windows with good thermal performance. Typically, double-glazed or triple-glazed windows with insulating gas between panes (argon or krypton) and a low-E coating are considered high-efficiency. Low-Emissivity (low-E) coatings prevent radiant heat from crossing the window plane, i.e. they keep heat inside in the winter and outside in the summer. Frame materials like fibreglass and wood have low rates of thermal energy transmission while aluminium and PVCu (Vinyl) have one of the highest negative environmental and health impacts.
Insulated Concrete Forms (ICF)
Insulated Concrete Forms (ICF) are formwork blocks created from insulative materials. We prefer Durisol due to its low embodied-energy and lack of petroleum-based compounds. The blocks are first laid in place, stacked and then concrete is then poured into the spaces within the blocks to provide rigidity to the wall structure. Advantages of ICF include good insulating properties, minimal thermal bridging, and a consistent air seal. An additional advantage of Durisol is the placement of the insulation completely on the outside of the concrete, allowing the concrete to function as an effective thermal and humidity mass.
Indoor Air Quality (IAQ)
Indoor Air Quality (IAQ) refers to the concentration of contaminants in the air as they affect occupant health and comfort. Superior Indoor Air Quality is achieved with careful interior material selection and an optimum ventilation strategy, ensuring both a healthy and a comfortable environment.
Indoor Materials
Interior Materials are selected for low emissions (low- to no-Volatile Organic Compounds (VOCs) and non off-gassing), resulting in healthier indoor air.
The recycled content and end-of-life recyclability of Interior Materials is also considered to reduce current and future waste to landfills, and reduce extraction of virgin natural resources.
Permeable Paving
Permeable Paving allows for the movement of stormwater through the surface, reducing runoff and filtering out contaminants before they enter the groundwater.
Rainwater Collection
Rainwater Collection harvests runoff water from roofs and other horizontal surfaces to be reused on the property. Uses include outdoor irrigation and, if municipalities allow, toilet flushing.
Active Building Strategies.
Active design strategies use purchased energy (including electricity and natural gas) to keep buildings comfortable. These strategies include mechanical system components such as air-conditioning, heat pumps, radiant heating, heat recovery ventilators, and electric lighting.
Active strategies also include systems that generate energy such as solar electric and solar thermal panels, wind turbines, and geothermal energy exchangers.
Grid Connected
A Grid-Connected building generates electricity for use on site. When electricity generation exceeds the amount required, the system supplies the excess power to the utility grid. Conversely, when the electricity demands of the building exceed the amount supplied on site, electricity can be drawn from the power grid. Optimally, a Grid-Connected building can be net-zero (or net-positive), meaning that the amount of electricity supplied to the grid is equal to (or greater than) the amount drawn from the grid. With the Hydro One Net Metering program, electricity generated by a building can be sent to Hydro One's distribution system for a credit towards electricity costs.
Net-Positive Cost of Energy
We recommend solar photovoltaic (PV) modules when the chosen site and project are suitable to harvest solar energy. Projects that generate electricity can become part of the Hydro One Net Metering program, which will provide a credit towards your electricity costs. Net-Positive Cost of Energy means that within the period of one year, a project generates enough energy to exceed the cost of energy they pay to their energy utilities each year, and thus create revenue for themselves through their solar PV system.
Solar-Electrical Power
Solar Electrical Power is generated by photovoltaic (PV) modules that harvest energy from the sun and convert it into electrical energy. For use in buildings, solar modules can be integrated into the design as cladding components or as sun-shades, mounted on the roof, or mounted on land adjacent to the building. Tracking devices can follow the path of the sun for optimal exposure.
Solar Thermal Energy
Solar Thermal Energy is heat energy generated by a roof-mounted solar collection device that absorbs heat from the sun. Flat-plate collectors are the most common type, where fluid is circulated through tubing to transfer heat from the collection surface to an insulated water tank. This strategy can be used to pre-heat water from the municipal main, or well, to decrease the amount of energy needed by an on-demand water heater.
Geothermal Heat Exchange
Geothermal Heat Exchange brings a building in harmony with the earth, taking advantage of subterranean temperatures to provide heating in the winter and cooling in the summer. Outdoor temperatures fluctuate with the changing seasons but underground temperatures (four to six feet below ground) don’t change as dramatically, thanks to the insulating properties of the earth. A geothermal system, which typically consists of an indoor handling unit and a buried system of pipes, called an earth loop, and/or a pump to reinjection well, capitalizes on these constant temperatures to provide “free” energy.
Wind Power
Wind Power is generated using turbines or windmills to harvest wind energy to convert it into electrical energy.
High Efficiency HVAC System
An HVAC system refers to mechanical systems for Heating, Ventilation & Air Conditioning to maintain the desired environmental conditions within a space. There are many different systems available but should be tuned to the building’s needs. Where possible, passive strategies and low-energy systems for heating and cooling are utilized to reduce energy demand. Passive strategies for summer seasons include: reflective roof surfaces, air-tightness and good thermal insulation. While passive strategies for winter seasons include: thermal blankets at windows, and the use of thermal mass.
HRV/ERV
Heat Recovery Ventilation (HRV) and Energy Recovery Ventilation (ERV) are dedicated venitlation systems that supply continuous fresh air to your home. Fresh outdoor air runs through the HRV/ERV which pre-conditions the air by transferring the heat (HRV) or heat and humidity (ERV) from stale exhaust air into the fresh outdoor air. This process saves energy in heating and cooling, resulting in lower energy bills and healthier indoor air.
In-Floor Radiant Heating
In-Floor Radiant Heating uses conduction and convection to exchange heat between a heated fluid running through tubes into the floor and then to the occupied space. Benefits include lower energy consumption compared to forced-air systems, a healthier indoor air quality, and a higher level of comfort.
Building Automation
Building Automation refers to the computer networking of electronic devices designed to monitor and control the HVAC, security, fire & safety, lighting, humidity and audio-visual control systems within a building. Automated Buildings are often referred to as “intelligent buildings”, “smart buildings”, or (if residential) as “smart homes”.
High-Efficiency Appliances
High-Efficiency Appliances must meet regulated targets for energy consumption. These targets are set lower than typical energy-use for the same appliance. In North America, we use Energy Star as a guide for high energy-efficiency standards for most household appliances.
Drain Water Heat Recovery
Drain Water Heat Recovery (DWHR) is the practice of recovering the excess heat we lose down the drain, particularly while showering. Water is expensive to heat and carries a significant amount of energy. The hot water that goes down the drain carries as much as 80-90% of the energy used to heat it. Drain Water Heat Recovery systems capture this energy to preheat cold water entering the water heater.
Electro-mobility
Electro-Mobility refers to the use of electrically-charged vehicles and other mechanical equipment. Electrical energy from renewable sources, as opposed to petroleum-based fuels, is promoted on each project and is ideally integrated during the design phase.
On-Demand Hot Water
On-Demand Hot Water is achieved using a tankless water heater, which instantly heats water as it flows through the device rather than heating, storing and re-heating a tankful of water until it is needed. The result is a continuous flow of hot water and reduced energy consumption. On-Demand Hot Water can be used for domestic hot water at faucets and showers and /or for radiant space-heating. Drain Water Heat Recovery can be effectively coupled with On-Demand Hot Water for optimal energy-efficiency.
Greywater Re-use
Greywater is a term used to describe water that has been used for showering, bathing, and hand-washing. It sometimes includes wastewater from kitchen sinks and laundry, depending on local by-laws. Greywater Reuse involves the collection and treatment of this water for use in toilet-flushing, outdoor irrigation and constructed wetlands, reducing the overall demand for potable (drinkable) water. Drain Water Heat Recovery can be effectively coupled with Greywater Reuse for optimal energy and resource-efficiency.
Reversible Ceiling Fans
Reversible Ceiling Fans are used to circulate indoor air and can be used in both heating and cooling seasons. In the winter, cool air is drawn from the floor up toward the ceiling, pushing warm air from the ceiling down into the occupied space. In the summer, air is directed down toward the occupied space to promote evaporative cooling.