Passive home designs have one common goal – to create energy-efficient homes (or commercial structures) without compromising on the health and comfort of the occupants.
With this in mind, the most efficient designs should not only conform to strict (and proven) standards, but they should also be practical. As a leading provider of architectural, structural, and MEP engineering designs, we can help you develop or evaluate passive home designs.
You’ll be better positioned to select designs that are suitable for your needs with our help. Here is a look at the principles of passive home designs and some tips to assess efficient blueprints. Read More About Click Here: Structural Design for a Residential Building.
A brief overview of the principles of passive home designs
Passive homes seek to enhance energy efficiency and simultaneously minimize the need for heating and cooling by focusing on the following principles:
- High-quality insulation
- Airtight construction
- Effective solar orientation
- Efficient ventilation and energy recovery
- High-performance windows
An efficient passive home significantly reduces the energy demands of a structure resulting in a positive environmental impact. But how can you tell the most efficient designs?
Efficient passive home designs should incorporate the above principles and conform to PHIUS+ Standards. These benchmarks are researched and established by the Passive House Institute US. The organization also performs the following functions:
- Lobbies for the mainstreaming of Passive Home Designs in America.
- Provides guidelines for designing passive homes that are eligible for certification in America.
Designers and providers of architectural engineering services generally concur that these standards are both effective and practical. Below is a look at what efficient designs should look like in light of the principles and PHIUS standards.
For homes in moderate climate zones, the insulation provided by furnishings and the drywall may be sufficient. There is no need for additional insulating materials. However, that is not the case for homes in temperate or extreme climate zones.
The first principle in passive home designs is high-quality insulation. Architectural blueprints that meet the passive home design criterion entail continuous insulation at all junctions. That means the structure has continuous insulation all around it (the slab, walls, and roof) without any interruptions.
The most efficient passive home designs often double the minimum amount of insulation required. They also use high-quality and environmentally friendly insulating materials such as sheep’s fleece and cellulose. But it is hard to achieve continuous insulation throughout the structure. Some junctions could have interruptions that would create a “thermal bridge.” The architectural engineering design of passive homes minimizes the occurrence of thermal bridges. However, heat loss is inevitable. Therefore, designers of efficient models give you an idea of how much heat loss to expect. They quantify it via modeling and calculation, and advice.
It would be impossible to maintain the desired air temperature in a porous structure. Therefore, the second principle – airtight construction – is a prerequisite of the first principle. Nevertheless, it is hard to imagine buildings without vents, windows, doors, and other necessary “air-leakage” points. These parts are essential. However, they complicate the need to maintain ambient internal temperatures without consuming extra energy. Plus, there is the problem of damp and mold in humid areas that have insufficient circulation.
Passive home designs use approaches such as caulking, high-quality MEP engineering, closed-cell insulation, and materials such as gaskets to plug air leaks. The most efficient passive home designs predict the air leakage rates and engineers use the information to design a balanced ventilation system.
Or a system where incoming clean air is almost equal to the outgoing exhaust air. Passive House Institute – US standards require that the supply and exhaust airflows be within 10% of each other. Moreover, where there is an unbalanced ventilation system, the net pressurization or depressurization should not exceed 5 Pa.
Effective energy recovery
Having an effective ventilation system means the home has excellent air quality, thus not compromising on comfort. However, it also means the structure would be losing energy when expelling exhaust air. Any incoming air should therefore be heated or cooled to maintain interior conditions. The resultant is a net energy loss. Efficient passive home designs minimize such losses by incorporating HRV (Heat Recovery Ventilation) or ERV (Energy Recovery Ventilation).
The geographical location of the structure determines the applicable energy recovery technique. Heat Recovery Ventilation systems maintain the humidity level within the building and are suitable for dry areas, comment Fantastic Electricians. Energy Recovery Ventilation systems extract moisture. They are ideal for high-humidity environments such as coastal areas.
High-performance doors and windows
Ordinary design homes allow for energy loss through windows and doors. However, the most efficient passive home designs minimize such losses by incorporating high-quality installations (doors and windows). The windows are often triple-paned with insulated frames and glass spacers. The installations are also only from credible suppliers who test and provide air-leak specifications.
Besides the material constitution and specs of the windows and doors, the placement is also essential. The orientation should optimize natural sunlight and heat. Windows and doors should face within 30 degrees of true south. Also, they should not be shaded or have any obstructions (by trees or other buildings) during the warm season.
Effective solar orientation
Energy conservation is a crucial aspect of passive home designs. With proper orientation, solar energy can contribute significantly to the lighting and heating requirements of the home.
Architectural designs in temperate zones aspire to optimize passive solar heating during winter and curtail overheating during the summer months. In warmer climates, efficient passive home designs seek to minimize overheating.
Efficient designs, therefore, incorporate windows with a high solar heat gain coefficient (SHGC) in south-facing walls. On the other hand, for the east or west-facing windows, the design could include overhangs, blinds, sun shades, or other techniques. This presentation by PHIUS provides insights on designing optimum window shadings in passive homes.
Passive homes also use darker colors on surfaces in direct contact with the sun during cold months to “collect” energy. Then, they apply different thermal distribution strategies to create passive solar heating throughout the structure. Effective passive home designs also incorporate deciduous trees on the east-west side of the building. The trees would block excessive sunlight during the summer months, and when the cold months set in, they shed leaves and let in solar energy.
High-performance doors and windows
Plugging air leaks and regulating ventilation is one milestone. But there is the issue of energy loss through windows and doors. The most efficient passive home designs incorporate high-quality installations (such as doors and windows) that specify the air-leakage rates. The windows also are often triple-paned with insulated frames and glass spacers. The door or window should also be high-quality, from credible suppliers with tested air-leak specifications.
Besides the material constitution of the windows and doors, the placement is also essential. The orientation should optimize natural sunlight and heat. Also, they should not be shaded or have any obstructions (by trees or other buildings), especially during the cool months.
Efficient passive home designs – a final word
There are many different techniques and strategies employed when creating passive home designs. But any design should essentially stick to the above principles and meet the standards. You may have to do some balancing between the costs and practicality. So, reach out to seasoned designers and get help on coming up with the ideal design. Some of the considerations to incorporate include:
- A simple thermal envelope.
- If it is a single-family house, the window area should be 10-15% of the wall area.
- A compact building for small structures. If it is a large one, it should have bump-ins for daylighting.
- Minimize “open to below” areas on the floor.
- The building should not be too small and detached.