Passive House Library

BC ENERGY STEP CODE

The BC Energy Step Code standardizes pathways to the next generation of buildings that aim to meet Passive House levels of performance for new construction by 2032. This is a provincial building regulation that was introduced in April 2017. Currently, numerous municipalities are already enforcing a specified Step level in the BC Energy Step Code. Overwhelming news for many Architects as the traditional prescriptive approach in the current BC Building Code would no longer be compliant when adopted by a municipality beyond Step 1. Essentially, a conventional house design will evolve into Passive House design by 2032 if not sooner. Click here to learn more about the BC Energy Step Code.

BUILDING ENCLOSURE

A building enclosure is also called an environmental separator in Building Codes. The building enclosure refers to those parts of the building which separate inside conditioned space from unconditioned or outside space, and includes exterior foundations, exterior walls, windows, doors, roofs and floors. A building’s enclosure can define its value, performance and architectural expression. A thoughtfully designed building enclosure can make a new building work more effectively for its owners, occupants and environment. With a full building enclosure renovation, it can also transform the performance of an existing building.

HEAT RECOVERY VENTILATION (HRV)

Heat recovery ventilation (HRV) requires a mechanical device and air distribution ducts that exchange stale indoor air with fresh outdoor air. Heat is transferred from the outgoing air to the incoming air by passing the two air streams through a heat-exchange core. The two air streams are kept separated, and only the heat is transferred to the incoming air, which is then circulated throughout the house. In most cases, fresh air is delivered to bedrooms and the living room, while stale air is removed from bathrooms, laundry rooms, and the kitchen.

In an airtight house, such as a Passive House, an HRV is much more effective at recovering a large percentage of the heat that would otherwise be lost by means of uncontrolled leaks/drafts through the building enclosure. This is a mandatory component in a Passive House which provides most or all of the heating demand significantly reducing the operating (utility) costs. A Certified Passive House requires a HRV with equal to or greater than 75% heat recovery efficiency with a maximum electricity demand of 0.45 Wh/m³.

HRV is absolutely essential for creating a healthy indoor environment and improving indoor air quality. A highly efficient HRV installed in a Passive House produces numerous benefits including the following:

Ensures delivery, distribution and circulation of filtered fresh outdoor air throughout the house
Controls indoor air humidity levels to prevent moisture problems such as condensation on windows and mold growth
Helps control odours and humidity levels throughout the house
Dilutes indoor air contaminants produced from off-gassing building materials and volatile organic compounds (VOC)
Provides better comfort by warming incoming ventilation air
Filters potentially polluted incoming air from outside

THERMAL BRIDGE

A thermal bridge may be linear or an isolated point of low thermal resistance in a building enclosure. Thermal bridging results in heat bypassing the insulation (thermal barrier) reducing effective R-value of the entire wall/roof/floor. Thermal bridges cause localized heat losses and may cause mould growth and structural deterioration. All thermal bridges must be accounted for when conducting an accurate energy model of a building. Akira Living personnel have extensive experience with Therm software to analyze any custom building enclosure junction to determine its PSI-value. Akira Living’s construction drawing details are evaluated with Therm to assess the impact and reduce or prevent thermal bridges. Thermal bridge assessment is crucial in both Passive House and conventionally constructed buildings.

BLOWER DOOR TEST

A Blower Door Test is conducted by a trained technician to verify the airtightness of the building enclosure to determine how leaky/drafty it is. This is a crucial test when building a Passive House and is mandatory if pursuing a Certified Passive House. For Passive House Certification the Blower Door Test must comply with the EN13829 Standard with an airtight building enclosure measured to be equal to or less than 0.6 air changes per hour (ACH) at 50 Pascal. The test is a simple procedure where a door fan is temporarily installed in an exterior doorway to pressurize and depressurize the building to 50 Pascal. This differential pressure measurement test corresponds to wind speeds of 15 to 35 km/h that can quickly suck out all the heated air inside a conventional building. This test should first be conducted when the air barrier system is exposed during the construction stage to help detect/repair air leaks and for quality assurance.

INFRARED THERMOGRAPHY

Thermography is the process of acquisition and analysis of thermal information from a thermal imaging camera (a.k.a. infrared camera). An infrared camera can be used to detect building defects by observing heat flow through the building enclosure. Infrared thermography surveys are non-invasive and may detect various defects in the building enclosure not visible to the naked eye including but not limited to the following: