HOTELL PASSIVE HOUSE
Sustainable Design Features of the Hotell Residence
Meeting with Surrey City Hall Sustainability Group December 8, 2011
Prepared by:
Teresa Hotell, owner
Ayme Sharma, MArch, LEED® AP, PHPP consultant Building Designer
Marken Projects
Specialists in passive, sustainable and healthy buildings.
Builder: Picosso Homes
Exterior walls: Durfeld Constructors
Teresa Hotell, owner
Ayme Sharma, MArch, LEED® AP, PHPP consultant Building Designer
Marken Projects
Specialists in passive, sustainable and healthy buildings.
Builder: Picosso Homes
Exterior walls: Durfeld Constructors
CONCEPT
The Hotell family residence is designed with the environment and family health as the primary considerations. The house will be home to 4 adults and 2 children: grand parents, parents, and children.
KEY FEATURES
Energy
The home will meet the Passive Energy House standard
Passive House Fundamentals
The revolutionary energy performance of Passive House buildings demands a rigorous and scientific approach to design and construction. This is achieved through a radically improved building science that combines informed design, airtight construction, super insulation and a heat recovery ventilation system to achieve the rigorous passive house energy threshold of an annual heating and cooling requirement of less than 15 kWH(m2a).
To put that into perspective, a passive home uses approximately 10% of the energy required to heat and cool a conventionally built home. The defining features of a passive house that allow it to achieve this annual heating requirement are detailed below. In summary:
- the building must be airtight (less than 0.6 time the house volume per hour);
- the building must be super insulated (R60+) with special attention given to
eliminating thermal bridging; - the building must use triple glazed windows with a U-value less than 0.8 and that
through proper orientation of glazing, heat the building passively; and - a Heat Recovery Ventilation system (HRV) must be incorporated to introduce
fresh tempered air.
Source: Canadian Passive House Institute
Energy performance savings of 90% in comparison to conventional Canadian construction do not happen by chance. If a building is to achieve year-round comfort in a cold or cool climate zone with such minimal heating/cooling energy use, then itʼs necessary to incorporate passive design fundamentals, including the following:
1. Pre-Planning
If you want to build a Passive House itʼs important to get qualified professional advice on achieving this standard at the beginning of the design process. Unless this is a clearly defined goal from the start of a project, the building will likely not meet Passive House performance standards.
2. Efficient Building Shape
Since the amount of heat loss from any building envelope is proportional to its surface area, the buildingʼs surface area must be minimized to achieve exceptional energy performance. Passive House designers use a ratio known as the ʻShape Factorʼ to assess buildings, this being the ratio of the buildingʼs surface area divided by its volume. By this measure, buildings with sprawling designs, exposed floors, heated garages etc. have higher shape factors, and will therefore experience higher heat losses, even if their floor areas are identical.
3. Solar Exposure
Passive solar gains normally form an important component of the heating requirements in a Passive House. In most regions of Canada high solar gains though south-facing
glazing are potentially available and need to be utilized on site through appropriate design if the Passive House Standard is to be achieved. At the same time, glazing on northern facades should be minimized. Skylights are almost always a poor design choice from an energy-efficiency viewpoint. Both winter and summer shading performance, as well as year-round comfort design requirements are determined in detail using the Passive House design software (PHPP).
4. Superinsulation
The insulation levels required for any building to achieve Passive House performance must be determined by modeling the building using the PHPP software and relevant climate data. To ensure accuracy this should be done (or supervised) by an experienced Passive House designer. Depending on the climate zone, houses built in Canada will likely need between three and seven times better insulation performance than that provided by current national and provincial Building Codes, in order to achieve Passive House performance. The designer must ensure complete insulation coverage for all parts of the building shell.
Source: Dürfeld 3D Wall and Floor Detail
5. Advanced Windows
As the thermally weakest part of a building envelope, windows are a critical component in Passive House design, often representing more than 50% of all heat losses in a building. Windows are also critical to interior comfort, and the interior glazing and frame surfaces need to remain warm enough on cold nights to minimize interior downdrafts in areas adjacent to the window. In all parts of Canada triple glazing is essential, with two low-e coatings and argon (or krypton) gas fill, as well as insulated spacers between each glass pane. It is also critical that window frames are insulated. Most windows currently sold in Canada meet few if any of these requirements.
6. Airtightness
Passive House buildings need to achieve very high levels of airtightness compared to conventional construction, in order to minimize heat loss from air infiltration, and also to protect the building structure against possible moisture damage.
7. Ventilation with Heat Recovery
All Passive Houses are fitted with a ventilation system which provides excellent indoor air quality and which has exceptional heat recovery performance.
Source: Dürfeld Passive House Construction
8. Ventilation Air Pre-heating
A simple and inexpensive geothermal heat exchanger is often incorporated into the Passive House heat recovery ventilation system, which allows for pre-heating of the cold incoming airstream and ensures that the HRV unit can be kept frost-free without the need for energy-intensive defrosting. Such systems can also provide some active cooling and dehumidification during summer.
9. Thermal Bridge-Free Construction
In order to certify a Passive House, the designer must demonstrate that all parts of the building fulfill a strict thermal bridge criterion. This is typically achieved via an
engineering heat loss analysis of various building components, such as wall-floor intersections. In practice, European Passive House designers have developed a large number of appropriate thermal bridge-free construction solutions, since most builders and architects cannot be expected to perform such calculations. Significant thermal bridging is found throughout all building envelopes in contemporary Canadian construction.
Source: PassivHaus Institut
Site
- The house will have a small footprint relative to other houses in Surrey
- The footprint is setback along south side of property to maximize southern passive
solar exposure
- The site was purchased with several things in mind:
- maximizing density: 2 families in 1 home
- accessibility to transport,shopping, medical and other community sources (library, recreation center, and pool)
-to address the potential needs of the elders of the family by having extended family available to provide care (saving health care costs)
-improve quality of life (Elder/child contact)
Water
• Rainwater collection system for toilet flushing and irrigation• Low-flow water fixtures• Solar hot water panes and drain water heat recovery will be utilized• Walled garden to provide a micro climate in which to grow food• Native plants and low impact landscaping such as permeable driveway material
Materials
- For this project, we intend to prefabricate the building shell including the exterior wall, roof, floor and interior structural walls. These components will be constructed inside a facility in Williams Lake, the large panels are transported onsite and assembled within a few days. The main advantages of this type of construction are:
- Quality: Built under controlled conditions indoors
- Ultra Airtight
- Material/Waste: significantly reduces material usage and waste
- Construction time: reduces project construction time by several month - Less disturbance for the site and the neighbours - Flooring and millwork from sustainable sources
- Regionally sourced materials
- Where possible, use recycled materials (counters, doors, etc. if possible)
- No VOC off gassing by use of “green” cabinetry, flooring, paints, and natural fibbers
Indoor Environment
Passive homes boast comfortable, consistent temperatures year-round, exceptional noise control, longevity and thanks to the constant introduction and cycling of fresh, filtered air, health benefits for those with allergies and asthma.
Future proofing
• Home will be built to last at least 100 years
• Home will be wired for future Solar Photovoltaics
• Home will be wired for future Solar Photovoltaics
Leadership and Innovation/Education
To our knowledge, this project is the first of its kind in Surrey. It will be a model for the future of buildings in Surrey and will hopefully demonstrate the possibilities for energy efficient, sustainable, healthy, and affordable homes.
The selected builder has been building homes in Langley and Surrey/White Rock for the last 20 years. He has no experience with Passive Homes, but is very keen to learn because he recognizes the potential of this kind of home. He will be working with Dürfeld Constructors of Whistler, BC - experienced Passive House builders.
Teresa and Alan Hotell are excited to be educating and advocating for health green homes for our community.
