Passive Building

Passive Building Is Affordable Promoting Comfortable and Healthy Living

Passive building is an international standard to produce very energy-efficient yet comfortable and healthy homes. It goes beyond having solar panels and low energy consumption appliances, but is a design-led concept rather than simply a better way of building.

What Is Passive Desing And Building?

A passive building uses a set of principles that help to achieve a demanding level of energy efficiency intended to give a specific level of comfort for the building occupants. Passive design is not an addition to the architectural design but is “a design process that integrates with architectural design.”

To achieve the best energy consumption and comfort levels, the design of the building looks at not only environmentally-friendly building materials and components but starts with the orientation of the building to gain maximum benefit from the sun’s position throughout the year. The designer assesses airflows, air-tightness and even body heat to reduce energy consumption. The design then goes into computer simulations to see what improvements can be made to achieve the optimum energy- consumption.

The concept originated in the US after the 1970s oil-shock but took hold in German and Scandinavia where energy-efficiency is much more to the fore than elsewhere. Now there are tens of thousands of passive buildings in northern Europe.

Given that the design of the building comes predominantly from managing air flows of the whole entity, passive buildings are mostly new builds although sometimes they can be retro-designed and renovated to achieve the passive energy standards.

What Does A Passive Building Give You?

In short, a passive building will produce energy savings of 90 percent compared to normal building design and construction methods. Not only is it a building standard for energy efficiency but it is also about making a home that is comfortable and affordable.

Passive houses limit their energy consumption for heating and cooling to 15kWh per square metre per year.

In colder countries, a passive house uses less than 1.5 litres of heating oil per year per square metre of living space, which is a marked improvement over other low energy consumption homes.

Similar energy savings are possible in warmer climates, but here the emphasis is on cooling instead of heating to maintain the comfort within the house.

A passive house pairs comfort during both winter and summer months, with reasonable construction costs.

Passive house design pays a lot of attention to the level of comfort, as they are designed to make use of energy sources inside a building that can come from body heat, appliances, or from the heat of the sun that enters a building naturally.

These houses must be airtight and air-change rates limited to 0.6/hr/.

What Does A Passive Building Include?

Passive building

Passive building schematic

Passive buildings start with the orientation of the building and any shade that it might receive. These two factors help to use the energy of the sun for heating during winter and reduce overheating during summer both of which reduce energy consumption and increase internal comfort.

A simple design of the building or the form, can significantly reduce energy needs. For example, a bigger building will have more empty space which needs heating to maintain comfort levels. A passive building will be designed with the users in mind.  Also, a simple design rather than a complex angular building will have fewer joins which reduces heat loss.

Energy gains and losses are optimised by employing a continuous insulation, sometimes called superinsulation, throughout the entire envelope of the house. Passive design also takes into account any potential thermal bridging. This is a fancy term for breaks in the insulation such as windows or doors, which leads to energy losses. Condensation on a window is a common example of a thermal bridge.

This does not mean that a passive house has small windows with little light coming in. Instead, the design will use double or triple glazed windows and high-performance doors.

Passive houses need to have a completely airtight envelope, that will effectively prevent any loss of conditioned air or the infiltration of the outside air. However, the building still needs to breath to manage any moisture such as human exhalation. This is managed with a heat-exchanger.

That leads onto the next key feature of a passive house, ventilation. Mechanical heat-recovery ventilation is the most common method that allows balanced heat and moisture recovery.

The last two factors are most often thought of as the energy-efficient tools – heating and hot water systems. However, unlike conventional low-energy boilers, the ones used in a Passive House are much smaller. Since the building is so well insulated from the design, the demand for heating is much lower. In fact, a larger boiler can be counter-productive because its output has to be cooled.

The Benefits Of A Passive House

By definition, a passive house is eco-friendly as it uses very little primary energy, thus reducing demand for carbon-based fuels. Any additional energy required during its construction is small, compared to the energy savings that a passive house makes in the long run.

The standards for building a passive building can be used not only for new buildings but also used to renovate an existing one, at fairly reasonable costs.

This concept produces consistent indoor temperatures in all seasons by balancing various design and construction factors to reduce energy needs. Air-tight construction and a high degree of insulation make passive houses extremely comfortable even in the most extreme weather conditions. Superb indoor air quality is assured by continuous mechanical ventilation that produces a continuous supply of filtered air.

Passive Building Certification

For verification, a Passive House is certified by independent third-parties so you know your new home is going to perform as you hoped, saving you money and giving you a more comfortable living space.

Certification can either be Certified Passive House Building for a brand-new house or EnerPHit Retrofits’ for renovations or retro-fitted homes.

If you are interested in the idea of a Passive Home, call me 0800 224 628 or if you prefer, you can email me at admin@cainbuilt.co.nz.

I look forward to hearing from you.

Tim Cain.