Posts Tagged ‘passive design’

There’s quite a fraction of people reading this series on LED lighting who will nod their heads in disagreement. You’ve probably heard from your friend’s that they are very-expensive, very-chic, or that LED installations go bonkers after a few months. The problem is not with LED. LED is one of the best lighting options for residences, when used correctly. An inexperienced electrician and incorrect buying decisions can do a lot of harm to the lighting of the house, to you and your pocket. Here’s what to bear in mind:
1. Buy the right type of LED for your requirements. There are low wattage LEDs, which will work on 1mA (very little) of electricity and there are also new High-Power, high wattage LED which will work on more than 1A (100+ mA) and produce over 1000 lumens. The low wattage ones are used singularly to create different effects, usually for decorative purposes. The high wattage ones are used in place of a light bulb, or used in an array to provide enough light for an entire room.
2. Both types of LED lighting have different requirements. Low wattage LEDs burn out very quickly if not used with the right kind of voltage. They require much less than what is available by default in homes. High wattage ones, on the other hand can work with what we have in homes but need adequate heat sinks that will absorb the extra heat they will produce. If heat sinks are damaged, the lighting will burn out in seconds.
3. LEDs are quite affected by ambient room temperature. Installing them into walls which are not properly ventilated or in rooms that tend to get warm affects their life expectancy, causing them to fade out faster.

If you’ve been to a house that was recently done up (in a rather fashionable manner) – you might have found a lot of small whitish lights used in places where the conventional bulbs and CFLs used to be. These tiny things are LED (Light Emitting Diodes) a new entrant in the field of home lighting.
LED is a certain type of lighting device which is being increasing used in homes for many reasons. Largely, they are used more for decorative purposes, but their efficiency and long-life as compared to other fluorescent and incandescent lamps have led to LED using lamps to be used as the main source of light in a house.
The main factor working in LED’s favour is its efficiency. Unlike regular bulbs and fluorescent lights, which waste almost 90% of the energy they consume in the form of heat, LED release very little heat, using up most of the energy to produce light. Thus, its input/output ratio is quite high, and typically LED’s last about 20,000 to 35,000 light hours (compared to CFLs which last 15,000-20,000 hours and incandescent bulbs which last about 1000-2000 hours). This makes them an extremely cost-effective option, when compared to other forms of lighting.
To add to this, LED is available in a variety of colours and can be used very effectively for home decor. Also, LED is a point source of light. Which means if LED lighting is recessed into a wall, all the light it emits will go straight ahead into the room? When incandescent bulbs are recessed, only a fraction of the light will actually make it into the room.

Although not new, structural insulated panels (SIP) have recently garnered more attention than ever, thanks to the builders’, manufacturers’ and homeowners’ interest in green building and energy efficiency. With a view to energy efficiency, SIP is a good option. If you’ve ever been involved with any kind of construction in any way, you will notice that builders often use what look like large boards in place of conventional stick frames. Essentially, they’re replacing traditional house envelopes with SIP – and the best part about SIPs is that they can be used in place of any building material. SIPs are used in place of exterior walls, roofing material, floor boards and insulating the foundation.
The most obvious benefit of SIPs is that they have excellent insulating properties. A house built with one of the first ‘versions’ of SIPs in 1937 is still standing, after years of withstanding Wisconsin’s severe climate. The house was dedicated by then First Lady Eleanor Roosevelt and is currently used as a day care centre by the University of Wisconsin. Since then, SIPs have gone through many changes. The SIPs today play a significant role in reducing a house’s energy consumption requirements – particularly heating requirements, are quite low on maintenance and high on durability leading to lower operating costs and are easier and more efficient to construct. The only possible drawback that we might consider is their suitability over the long term in Northwest wet weather.

Quite frankly, it is not to much effort. Building technology has developed to a great extent since the passivhaus standard came into existence, and it is quite a bit easier to build a passive house now than it was 10 years ago. Most of the building material that you require are easily available. Passive houses are as comfortable to live in as any other homes and in fact are healthier and safer because of the building design.

Passive houses are more expensive to build than conventional homes because of the materials required between five and ten percent depending on size. However, over the long run, they have proven to be much cheaper. When you look at how much a conventional home costs in terms of heating, cooling, ventilating, electricity, and air conditioning – a passive house turns out to be a cheaper bargain.

Passive homes are not that uncommon either. Although it is difficult to find a completely passive house in the US – they’re common in the UK and across Europe. Closer to home, we have green homes that make use of some of the principles of passivhaus and add their own two bits to create an energy efficient green home. In Washington DC, we have architect and green builder Travis Price’s four story green home, just about 10 minutes from the White House. His house was featured on the Discovery channel’s World’s Greenest Homes – which, by the way, is a great show to see how much and how easily people can build green homes for themselves.

4. Ventilation: Ventilation is properly controlled in a passive house, by means of a mechanical heat recovery ventilator. Although HRV are used in most houses, passive homes use an extremely efficient one, since no other heating or cooling device is used in the house. Most passive houses use both – air to air and earth to air heat recovery systems – depending in the size of the house and climate.

5. Air-tightness: Air-tightness is an extension of the ventilation requirements. Passive houses don’t make use of any HVAC systems – only a HRV system. Thus, it becomes very important that air doesn’t pass through the house in any other way, otherwise, the HRV systems will not be able to perform optimally. Passive houses are therefore super air-tight, much more than conventional houses. The building envelope is sealed thoroughly, and so are any service components that go through it.

6. Space Heating: This is a pretty novel concept in the passivhaus technique. When all the previous measures are not enough to heat a particular house, passive houses use heat generated within the house due to electrical appliances, lights, human beings and animals to heat it. Other than this, some houses install a small or heating device (running on renewable energy) that is integrated with the ventilation system. Some houses also use a micro heat pump that can recover heat from the air escaping through the ventilation system. Together, all these ideas make a conventional heating system quite unnecessary.

7. Electrical Appliances: Passive house use low wattage electrical appliances, CFLs and intelligent installation to minimize the use of electricity.