Passive Design Fundamentals
5 PH Design Principles
This Quantum owned illustration is to illustrate the 5 PH Design Principles: airtight, super-insulated/thermal bridge free, efficient shape, high quality windows & doors, efficient ventilation with heat recovery.
- Thermal Bridge Free & Super-insulated: Passive House buildings have a ‘super-insulated’ continuous layer of insulation with no thermal bridges (heat transfer highways) much like a warm blanket . The amount of insulation required for a passive house building is specific to the design and site-specific climate data. This is determined by modelling the building using PHPP (Passive House Planning Program) software. Often, larger buildings with good Shape Factors (ratio of volume to surface area) can have reduced insulation compared to a smaller building in the same. Either way – reducing thermal bridges greatly reduces heat loss. location.
- Orientation & Solar Exposure: Passive House building design uses the ‘free’ energy from the sun to heat your building in the winter while shading it from this heat in the summer. The design takes advantage of the sun having a lower angle in winter (allowing the sun in) and higher angle in summer (allowing the sun to be shaded out). Assessing the building site for solar potential and orienting the building appropriately are key steps to achieving passive house energy efficiencies.
- Air tight! Passive House buildings must achieve very high levels of airtightness, compared to conventional and (even) R2000 construction, in order to minimize heat loss from air leakage, and also to protect the building from moisture/rot or mould damage from rot or mold that can be caused by moisture vapour traveling through that same air flow. Supported by building science, Quantum’s building envelopes that are not only airtight but also “vapour breathe” using high tech membranes that operate much like a Gortex jacket does – they block airflow very well, but allows moisture to escape the structure when required.
- Efficient Ventilation: Passive House buildings include mechanical ventilation that regularly introduce and circulate fresh air throughout the living space ensuring excellent indoor air quality. High levels of heat recovery and low costs of operating the HRV (Heat Recovery Ventilation) or ERV (Enthalpy Recovery Ventilation) are key components of a Passive House quality ventilation system. Enthalpy Recovery Systems also assist in maintaining interior humidity during winter. A system properly designed for the building significantly improves the comfort and ultimately the performance of the building.</p>
- High Quality Windows & Doors: Windows are a critical component in any building, often resulting in 50% or more of all heat loss in a conventional home. Passive House certifiable windows are exceptionally air tight, wind/weather resilient and insulate exceptionally well, while allowing solar heat gains (where desired). When specified appropriately to the building site climate, they are key contributors to maintaining interior comfort and hygiene (think no drafts, no cold spots, and no condensation). Extra attention and design emphasis is given to Passive House windows and doors: the window glazing, frame, spacer, solar heat gain value (ability to let solar heat through), u value (resistance to heat loss) and how they are installed are carefully considered and planned.
Detailed planning and energy modelling based on physics allows us to know the energy performance of the building prior to construction. From this information we can extrapolate operating costs. We have standard testing, documentation, and quality control measures built into our Passive House process in order to guarantee the desired outcome. The international Passive House Institute offers 3rd party evaluation building certification with the option of pre-certifying prior to construction.
Efficient Building Shape
Passive house design minimizes the building surface area to achieve exceptional energy efficiency. This is because the amount of heat loss through the building envelope, (the physical separator between the conditioned and unconditioned environment of a building) is proportional to its surface area. The ratio used to express this is known as the 'Shape Factor' and is the ratio of the building's surface area to its volume. Buildings with sprawling designs and exterior wings , alcoves, etc. in the design have a higher Shape Factor, and will not conserve heat as well as a more compact or streamlined building, (even if they have the exact same amount of usable floor space).
Thermal Bridge-free Construction
Passive House construction aims to be thermal bridge-free. Thermal bridges are locations where heat and/or cold transfers rapidly from the inside to the outside or vice versa. Thermal bridges affect your heating and cooling load much more than one would think, and they open the door for condensation and mould to develop.
Typical locations to avoid thermal bridging are at wall, floor, patio and balcony junctures, as well as at edges, corners, connections, and penetrations. Therefore these must be planned and executed with great care. Quantum Passivhaus’ panelized building systems are thermal bridge free.Photo Credit to Penny Beaudry