Eco building
Not only do the walls, slabs and roof need to be properly insulated, but so do all of the openings. High-quality windows are one of the biggest up-front expenses in a Passive House, but they contribute to a large portion of the energy savings. We can insulate like crazy, but if we use subpar windows, all of the heat will exit through the glass. The building envelope, which is like its skin, is only as strong as its weakest point.
A home built to the Passive House standard is one that remains comfortable through all seasons without employing an active heating or cooling system. Depending on your country and the localized standards, a project must meet maximum annual energy consumption limits to be considered. Historically, and still in Europe, this was 15 kilowatt-hours per square meter each year. The U.S. standard has since made changes to that limit in an attempt to address specific climate zones. However, as an order of magnitude, we’re talking about 60 to 70 percent, sometimes even more, in energy savings relative to conventional buildings.
Given the ability of thermal mass to control temperature, you would think we would all be using it. But, as with many investments, the initial outlay can be expensive. Precast concrete walls are more expensive than Gyprock. Weigh the long-term benefits, though, because future savings are likely to outweigh the up-front investment.
Thermal mass is particularly good for climates with a high diurnal difference, which simply means a big difference between day and night temperatures. This is the case for many dry desert climates, but less so for tropical climates (though designed effectively, thermal mass can still be used for tropical climates). Use of thermal mass will help to regulate these environments and keep the temperatures constant.
“Thermal mass” describes a material that has the ability to absorb and store heat. Materials with a high thermal mass take a long time to heat up and cool down. So in cool weather, a material with thermal mass can absorb heat, store it and slowly emit it at night, while in warm weather, it can help to maintain a building’s coolness when used correctly. Brick, for example, has thermal mass, but wood floors and brick veneer do not.
6. Rammed Earth in Australia With its rammed-earth walls, sunny north-facing windows and solar-heated water pipes embedded in concrete slab, this home works hard to capture and store heat. This combination of features is so successful that, even on the hottest days, all the homeowners need to do to cool down is to crack open a few windows and turn on the ceiling fans. The house and water are heated together, with the domestic hot water also heating the concrete floors in winter. The water is solar-heated and boosted by a high-efficiency heat pump.
5. Water Wise in Pennsylvania In addition to other energy-efficient features (like radiant heat floors), the owners installed a greywater system that collects rainwater from the roof and channels it into two large tanks buried underground. After going through a filtration system, the water is used for the home’s toilets, laundry and exterior hoses. The exterior siding was burned by hand before installation, emulating a traditional Japanese technique called yakisugi-ita. The burnt layer acts as a protective coating on the wood, repelling water and insects. It also looks amazing and has a very organic feel.
4. Passive House in California Starting from scratch allowed the owners to get exactly what they wanted in a home, which for them meant a family home built upon a set of Passive House principles — the aim being to reduce energy consumption. Airtight construction, well-insulated windows and walls, and carefully positioned window openings work together to create an interior that can remain comfortable year-round without conventional heating or cooling, which translates into significant energy savings. This home also features a heat recovery ventilator system. This system continuously extracts moist air from wet rooms (such as the kitchen and bathrooms), and then filters and recirculates it to balance the air throughout the house. This process can recover up to 90 percent of the heat in extracted air, adding up to significant energy savings.
3. LEED Leader in Utah This modern home earned Utah’s first LEED-H Silver certification, thanks to its fire-resistant exterior, compact footprint and overall energy efficiency. Thoughtful siting on the lot takes advantage of the sun’s path, and radiant heat floors provide efficient warmth during Utah’s chilly winters. The owners took a year to analyze the site, tracking summer and winter solstices and studying the surrounding environment in each season. T'DAL COMMENTS : we need to spend time there too before planning the building !..
2. Radiant Heat in Massachusetts What makes it efficient: In an area with hot, humid summers and freezing-cold winters, heating and cooling costs (especially for an older home) can be astronomical. When renovating their 1950s bungalow, the owners installed an efficient radiant heat floor system and supplemented it with south-facing windows to collect solar heat. In the summer, lush oak forest surrounding the home provides shade, keeping the home cool; in winter, the combination of passive solar windows and efficiently heated floors keeps the house toasty at a fraction of the cost of the pre-remodeled home. Excess heat is collected from the air on the upper floor of this three-level home and circulated back to the lower floors using a high-velocity air system.
When it comes to making energy-efficient design choices, there are lots of things you can do without remodeling (or moving), including choosing appliances with the Energy Star label, switching to compact fluorescent or LED lights, and improving insulation and windows. But if you are looking to remodel (or build from scratch), even more options begin to open up. With the thoughtful use of energy-efficient architecture and systems — like passive solar design, radiant heat and rammed-earth construction — even a large home can end up more efficient than a traditionally built home of the same (or even smaller) size. 1. Solar Powered in Oregon What makes it efficient: When building their new home, the owners installed solar panels on the south-facing roof and put in a solar hot water heater. In the summer, even with air conditioning, the electric bill isn’t more than $8 per month. They were able to use the wood from two black walnut trees that needed to be removed from their backyard to create hardwood flooring for the home. T'DAL IDEAS - fencing / flooring from the existing alien trees !
think of the building envelope as being like an inflated balloon. One hole in the balloon, and all the air will escape. It doesn’t matter how sturdy the rest of the balloon is. So not only do we want to have a consistently insulated building envelope, but we also want to avoid any air leakages where hot air can escape in the winter or enter in the summer.
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