» Passive House

Passive House North West comes to Olympia

Cory — Sat, 19 Mar 2011 14:41:43 +0000

It was very exciting yesterday to attend the 2nd annual regional meeting of Passive House Northwest held at Evergreen State College. Last year at the 1st one, we had about eighty people attend. This year my guess would be well over three hundred. This didn’t surprise me because the movement is really picking up steam in the US. And why not, who doesn’t want to live in incredible comfort, have a home with minimal carbon foot print, as save a ton of money in the process. And because they are so energy efficient they only require about a quarter of the solar panels of a code built home, to supply all of you energy needs. Imagine never haveing to pay a power bill again.

The conference featured several talks on methodology, along with case studies of actual homes that have been built in the northwest. The speakers ranged from building scientist, builders and passive house consultants, to even the home owners of Passive House’s. The talks were very detailed, and incredibly informative. Also there where many vendors promoting the latest advances in things like windows, Heat Recovery Ventilators and air sealing tapes and fabrics. For me the most telling reason of why this is the right approach to home building was hearing the home owners, the folks who actually paid for and live in the homes, explaining how wonderful there new homes where.

I celebrated having attended the conference by meeting with my design team and the homeowners of what will become our first Passive House. We settled on a floor plan and will meet at the Patterson Lake site next week to review elevations and exactly how the home will sit on the sight. It very exciting and I will try to keep you updated as we move through the process.

Water savings is in the Flush

Cory — Fri, 26 Mar 2010 08:29:59 +0000

According to certain estimations, the average person flushes 35 gallons of water down the toilet, everyday. Considering you’re a family of four or more, you can safely presume that nothing less than 300 gallons of water are being used just to flush toilets, other uses of water notwithstanding. Although water is not really expensive in the US (so far) it’s only a matter of time before we begin to feel the pinch. And the ironic part is: despite the fact that it is as cheap as it is, no amount of money can buy or create water, when it’s gone, it’s gone.
So what can we do to prevent this bleak situation? Get new toilets. Conventional toilets use about 5 gallons of water per flush, significantly more than the new toilets, which use about 1.6 gallons. Going by that estimate, you can save phenomenal amounts of water, anywhere between 8000 to 20000 gallons a year, depending on your current usage. This translates into some nifty savings on cash too, upto $100 per year.
The 1.6 gallons per flush (gpf) limit is the newest upper limit enforced by the EPA for toilets, which means there are also toilets that use lesser amount of water, some even lesser than 1 gpf. Many homeowners worry that such ‘low-flow’ toilets will also be low on efficiency. However the latest generation of toilets are high on efficiency while being low on water consumption. Watersense labeled toilets are some of the best you can find today in this category.
Cost is another factor that bothers many homeowners when we suggest low-flow high efficiency toilets. Although these toilets are expensive than normal toilets, the annual savings on water bills pretty much offset the initial costs. In fact, according to certain estimations, the ROI on water efficient toilets is about 50%. Altogether, this makes water efficient toilets a very sensible option if you’re going to remodel your bathroom.

Windows and insulation

Cory — Sun, 24 Jan 2010 08:58:11 +0000

Sometimes getting the U-Factor, SHGC and VT values right is not enough. Often, the installation of the window itself, i.e. the entire window assembly can have flaws. These flaws result in air leakage – one of the main obstacles in trying to achieve energy efficiency with the help of windows.
If your house is built on the Passivhaus principles; or you are looking at seriously reducing your HVAC requirements (and thus the bill) then air leakages through windows can punch a large through your plan. Some energy efficient windows specify the AL value (expressed in cubic feet of air passing through for every square foot of the window assembly) between 0-1. The lower the value, the lesser the leakage. The industry-accepted value is 0.30.
Another problem for insulation is condensation. If you live in cold areas, you’ve probably seem frost or dew on the edges of the windows. Looks quite ‘Christmassy’ but it only means that much more heating load. Condensation happens when inside warm air comes into contact with cold panes and glass, which essentially means your windows are not doing such a good job insulating.
With condensation and air leakage, there aren’t fixed ratings to go by. However, certain materials and window technologies work better. For example, if you’re opting for multiple pane windows, looks for stainless steel spacers, or thermally improved spacers made from silicon foam or butyl tape. These spacers might be more expensive, but they are better are insulating, sealing and thus preventing unwanted heat transfer, while at the same time allowing from seasonal expansions and contractions in panes. Similarly, opting for energy efficient windows with two or more panes or glazing reduces condensation even at indoor humidity levels of 45-60%. This is especially true of windows with argon/krypton glass filled windows.

Windows and Natural lighting

Cory — Wed, 20 Jan 2010 08:09:34 +0000

It is very evident that the larger your window, the more natural light it will bring in. Depending on the positioning of your windows, and its visible transmittance (VT) value, your windows could provide you with enough natural light to greatly minimize if not eliminate electric lighting requirements during daytime.
VT values are generally given between 0-1. A rating of over 0.70 is the highest you can get with clear glass windows devoid of any coatings or tints. The more the number of panes, coatings and tints the lower the VT value.
A high Visible Transmittance has another advantage – it eliminates the cooling function which is usually required in a house that uses electric lighting. A high VT value is especially important when a home is built using passive house principles or design.
However, one thing to consider when it comes to VT, is that a window with a high VT value, will also admit that much more solar energy (heat) inside the room. Thus, a clear glass window with a VT of 0.8 will also have an SHGC of over 0.60 – something not at all desirable in a warm or sunny climate.
To get around this, one can use Low E coatings, which are invisible, and yet block heat gain considerably. These coatings also protect indoor furniture and upholstery from the damaging effects of UV rays. Another way is to have operable windows that you can open up to air the room out frequently. Needless to say, a good ventilation system is important when you have large windows and a sunny climate.
For windows that are low on SHGC and high on VT, look for a high Light-to-Solar gain ratio. This determines how much more light is let in without adding to the heat.

Windows and Heating

Cory — Sun, 17 Jan 2010 08:04:21 +0000

There are two ways that windows help in heating and cooling – by preventing heat loss from the room, and by taking in heat from the outside. The former is measured by a window’s U-Factor and the latter by SHGC. U-Factor measures how much heat is lost through the window. The actual math gets quite complicated – U-Factor tells you how much heat is lost in one hour for one square foot at a certain temperature. A low U-Factor value (usually of 0.35 or lesser) means less loss and thus better insulation. Conversely, some windows may even mention an R-value, which is a measure of insulation. A low U-value corresponds to a high R-value.
SHGC is a value between 0-1. The lower the value, the less the amount of heat a window admits. Depending on the climate and your heating/cooling requirements you will need to pick a window with the right combination of SHGC and U-value. In cold climates, you want a U-value lesser than 0.35 combined with a high SHGC of around 0.60 or higher. This will considerable reduce the load on your heating system. For warm climates, you want the opposite – a low SHGC of less than 0.40 with a high U-value.
Does this mean you will have to change windows to match the seasons? Not necessarily. A metallic oxide layer (called a low E coating) applied on the outside keep the heat out, lowering the SHGC and when applied on the inside decreases the U-value. Even tints work well, though they only reduce the SHGC value.
Does material matter? Very much so, windows made of wood are not very good on insulation, while vinyl and fibreglass frames have the lowest U-values. Metal should be your last option when looking for insulation.

What makes windows eco-friendly?

Cory — Thu, 14 Jan 2010 13:38:32 +0000

No, we are not switching to promoting green software – we’re going to stick to good ole’ hardware and home building. For a long time, windows have been thought of just as basic necessities to a house, or as ornamental and status-symbols. However, windows are a big factor in terms of our electricity bills, keep us healthier, make our homes last longer, save energy and essentially, save the planet. However, they can do all this and more.
Eco-friendly windows are essentially energy efficient windows. The make, material, frame, size and positioning of windows has a great impact on interior lighting, indoor temperature, heating & cooling systems and indoor air quality. Energy efficient windows work at maintaining optimal levels of all these aspects and thus significantly reducing our bills and our carbon footprint. And with the new eco-friendly wave taking the construction industry by storm, energy star certified windows are easily available. Also, the certification system is such that it works well for different kinds of windows that are made for different home requirements and weather conditions.
Yet, it can still get quite confusing and most of us are not quite familiar with scientific window terminology. Essentially, when you buy energy efficient windows, you will come across a lot of numbers and ratings. There are five things you need to look at:
1. U-Factor (Level of heat transfer)
2. Solar Heat Gain Co-efficient (Heat capturing capacity)
3. Visible Transmittance (Light Transfer)
4. Air Leakage and
5. Condensation Resistance
And that’s why we have a series of how to understand and buy energy efficient windows – without wishing you’d done more math in high school.

It’s important that you install LED’s correctly

Cory — Wed, 02 Dec 2009 08:13:21 +0000

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.

LED’s offer huge Enviormental Savings

Cory — Mon, 30 Nov 2009 08:08:40 +0000

The main reason we’ve included LED in our recommendations, is because they’re quite eco-friendly, compared to all other options. LED produce much more light per watt of electricity. To be precise they produce around 18-22 lumens per watt, much higher than the incandescent and fluorescent lamps. This means they use less power to produce more, which cumulatively adds up to a lot of energy savings. In fact, the US DOE estimates that if LED lighting were used on a large scale, it would convert to savings of $265 billion, reduce electricity demand for lighting purposes by 33% ; and avoid the set up of 40 power plants across the country.
Also, every time you turn on the lights, you’re contributing to CO2 emissions to the tune of 196 pounds per year, for every light bulb in your house. LED lamps bring this to just 63 pounds every year. LED lighting is also non-toxic, it does not contain mercury like fluorescent lamps and thus recycling them is less hazardous. A few other benefits:
• LEDs are extremely small and are available in different colours. This goes well when you try to get creative with lighting in your house.
• LEDs can be dimmed quite easily. Repeated on-off cycles don’t damage LEDs the way they damage other lights. Thus, using LEDs for Christmas lighting is the ideal option
• They’re shock resistant, not fragile like usual bulbs.

How do you build a Passive house? Part II

Cory — Tue, 13 Oct 2009 08:18:15 +0000

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.

How do you build a Passive house?

Cory — Sat, 10 Oct 2009 08:11:31 +0000

By using certain principles for building aspects. The passivhaus technique achieves its standards by improving on many aspects of designing and building, particularly:

1. Passive Solar Design: This entails using naturally available sunlight, the suns’ daily and annual cycles to maintain a comfortably warm home without using other heating and ventilation system. This is done by building compact structures, window orientation, using lightweight materials and other techniques.

2. Superinsulation: The walls, floor and roof of a passive house are highly thermal insulated to prevent heat from escaping. Most houses have some form of insulation, however, they will depend on traditional temperature control devices to maintain constant temperatures throughout the house. Passive houses are superinsulated, such that the walls themselves are made up of insulating materials. Because of this, there are no thermal bridges, and there needs to be no external insulation of any kind.

3. Advanced Window Technology: Windows play an important role in designing passive houses. Window placement, size, alignment, material and design help to increase natural lighting in the house without adding to the heat or using electricity. Windows for passivhaus are differently manufactured and are made with extremely thermal resistant. The glass also is generally filled with argon or krypton gas which reduces heat transfer either ways and absorbs UV rays.