Being part of the group around our newest book “Simply GREEN – A quick guide to energy and environmental assessment certifications of building”, I have learned a lot about various energy and environmental certification systems. Recently I visited the workshop on Active House at the CLIMA 2013 conference and I have learned about the existence of another certification scheme created by Active House Alliance. This article is a summary of the specifications for designing an Active House, a building that combines energy efficiency with specific attention to user comfort, indoor climate and the environment.
I must admit that I was a bit hesitant to a new certification scheme for sustainable buildings, but the discussion at the workshop on Active House at the CLIMA 2013 conference was informative, although the presenters had to basically defend why they have created another certification scheme. I will let it up to you to decide if you want to know more about this certification, or if you think that a new certification scheme is not necessary and we need to focus more on the existing certification schemes.
The evolution of the Active House concept is intended to be used as a guideline at an international level, and can be used as a tool for designing nearly zero energy buildings. Its goals are to seek innovative technical approaches, keep the architectural quality and environmental design, and secure energy efficiency of buildings. The main principles of the Active House concept are comfort (daylight, thermal environment, and indoor air quality), environment (environmental load, freshwater consumption, and sustainable construction) and energy (energy demand, energy supply, and primary energy performance). There are also qualitative parameters including demand on individual products and construction elements, architectural design solutions and demand on individual appliances.
The parameters for comfort deal with view, visual transmittance, glare management, daylight in secondary room, individual controls in winter and summer, system interface, draught, individual control of air change, dampness, low-emitting building materials, inside system noise, outside noise, and acoustic privacy. The energy parameters deals with demand on individual products and construction elements, architectural design solutions, demand on individual appliances, design, origin of energy supply, energy use and CO2 emissions, on-site control of solutions and products, air permeability of the building, thermal bridges, qualification of the controller. The parameters for environment are LCA of the building, appliances, use of grey or rain water, job site management, disassembly, biodiversity, building traditions, active outdoor living, street and landscapes, infrastructure, accessibility, ecology and land use, and climate changes. Building management is one of the criteria insuring that the building works as designed, and contains following parameters: management of energy, management of indoor climate and management of environment.
“Integration of each parameter describes the level of ambition of how “active” the building has become (for a building the level of ambition can be quantified into four levels: 1 – the highest level and 4 – the lowest level).”
Compared to the other certification schemes, the Active House concept goes deeper into each issue, for example daylight. There are four levels for the following issues within the daylight conditions: daylight factor (level 1: DF > 5% on average, level 2: DF > 3% on average, level 3: DF > 2% on average and level 4: DF > 1% on average, * average is calculated using a validated daylight simulation program) and direct sunlight availability (level 1: at least 10% of probable sunlight hours down to level 4: at least 2.5% of probable sunlight hours).
All others requirements are evaluated using the very same four levels and detailed levels can be found at the website of Active House. Thermal environment has two requirements: the maximum indoor temperature and the minimum indoor temperature for rooms based on the usage. And indoor air quality has a requirement for standard fresh air supply based on concentration of CO2.
“The design of an Active House is based on the Trias Energetica approach to sustainable design. The main focus of the concept is the fact that the most sustainable energy source is saved energy.” This means to optimize the design to reduce energy demand of a building using energy-efficient and architectural measures such as orientation, materials, and shape of the building; and also to use renewable resources and CO2-free energy resources directly in a building or close by. The remaining energy demand can be covered by fossil fuels but through highly-efficient energy-conversion processes.
The criteria for energy demand (space heating, water heating, ventilation, air conditioning, cooling, technical installations, and electricity for lighting) is based on national calculation and national definition of heated floor area, and otherwise follow the national rules. The four levels for annual energy demand are: level 1: ≤ 40 kWh/m2, level 2: ≤ 60 kWh/m2, level 3: ≤ 80 kWh/m2 and level 4: ≤ 120 kWh/m2. The energy supply may come 100% from renewable resources (level 1), ≥ 75% (level 2), ≥ 50% (level 3) and ≥ 25% (level 4).
The annual energy performance including CO2 emissions of a building is based on an equation: the primary energy performance = (energy used – renewable energy supply) x national primary energy factors. All values are to be monitored on a yearly basis and metering. The criteria for four levels are: < 0 kWh/m2 for level 1, 0-15 kWh/m2 for level 2, 15-30 kWh/m2 for level 3, and ≥ 30 kWh/m2 for level 4.
The environmental requirements deal with primary energy, global warming potential, ozone depletion potential, photochemical ozone creation potential, acidification potential, and eutrophication. Also among environment parameters belong fresh water consumption and sustainable construction (recyclable content and responsible sourcing).
It can be said that the Active House scheme is more describable than other systems and goes more into detail. Still it is based on the national requirements and standards, which might be tricky. It might use many fancy words but it goes deep in some areas of buildings. The question is: Is it going deep enough? Is this just another European certification scheme or can it be used worldwide? Is the scheme too mandatory or too little demanding?
Read more info at www.activehouse.info