It took awhile to write this article, get more information and convince myself how to address the issue in a better way.
Thanks to the advancement of microelectronics, we have reached a level where we can measure almost everything and compare the measuring result with standards for safety and comfort while also protecting the environment from further damage. Building homes is also affected by the technology. We can measure the heat generated and dissipated to and from the house, the air coming out of the house and more.
It Started with a Cup of Coffee
Last week my good friend and I went to Starbucks near my office in New Westminster to energize ourselves with coffee and chat for a bit. My friend is environmentally conscience. He always travels with his Starbucks thermos mug. As for me, I usually prefer a standard Starbucks paper cup. Both of us order Starbucks tall coffees. I drink my coffee from the standard Starbucks paper cup with a sleeve to protect my fingers from the heat, but my friend uses his thermos cup for his coffee. He doesn’t need to have a sleeve.
For about 15 minutes we debate while driving without taking a single sip of our coffees. After a long silence, we each grab our cups and take a sip. His coffee is still full of flavour and hot. My coffee has lost its flavour and is cold. It is not the coffee but the container that makes a big difference. My friend is enjoying his hot coffee. The thermos mug maintains the heat generated by the coffee, but my paper cup has lost almost all the heat energy to my car and our surrounding.
Understanding the Concept of Passive Homes
That takes me to the picture I have seen when I read a book about the passive house. The lecturer shows us two cups- one with thermal protection, like my friend’s mug, and one like my paper cup. I decide to write a series of articles about a passive house ( Energy efficient houses) to give awareness to the public and share what is the main difference between standard homes and energy efficient or passive homes. Like our cups of coffee, the passive house (thermos mug) contained the energy in the house while the standard house (paper cup) dissipates energy out. The main difference is the way we protect the inside and outside temperature and maximize the comfort.
Let me dive dipper, It is confusing to the public as professionals and builders use different names like energy efficient house, step code, passive house, LEED, LEEP etc…
Wikipedia Definition of a Passive House
“ Passive house “( German: Passivhaus) is a rigorous, voluntary standard for energy efficiency in building, which reduce the building ecological footprint. It results in an ultra-low energy building that requires little energy for space heating and cooling.
Passive Home Standards
Passive house standard originated from a conversation in May 1988 between Bo Adamson of Lund University, Sweden and Wolfgang Feist of institute fur Wohnen und Umwelt ( Institute for housing and environmental, Darmstadt, Germany). Later this concept was further developed through a number of research projects.
According to Wikipedia, in order for a building to fulfill Passive house, it has to satisfy the following requirements
- The building must be designed by an annual heating and cooling demand as calculated with a passive house planning package of not more than 15 KWH/ Square Meter per year in heating and cooling energy or designed with a peak heat load of 10 W/Square Meter.
- Total primary energy ( source of electricity) consumption ( primary energy for heating, hot water & electricity) must not be more than 60 KWH/ Square Meter per year.
- The building must not leak more than 0.6 times the house volume per hour ( 50 less than or equal to 0.6/ hr) as tested by blower door or alternate when looking at the surface area of the enclosure, the leakage rate must be less than 0.05 cubic feet per min
By reading the above points, you might ask what are the standard house primary energy concept of the heating and cooling demand or the leakage factor. I ask the same question, we will show you shortly to compare how huge the difference will be.
Energy Efficient Home Building Concepts
The passive house is not energy standard but an integral concept assuring the highest level of comfort. The exact definition based on my mentors will be a follows:
“ A passive house is a building for which thermal comfort ( ISO 7730) can be achieved solely by post heating or post cooling of fresh air mass, which is required to achieve sufficient indoor air quality condition without need of additional circulation of air.”
Some Truth about the Passive House
- Up to 90% reduction on heating and cooling demand
- Precisely define before 25 years
- 60,000 projects worldwide
- Applies to any building ( new or renovation)
- Can be achieved in all weather conditions
- Focus on building envelopes ( see my coffee example in the second paragraph)
- Major emphasis on comfort and internal air quality.
- High-quality construction
- The design must be verified with PHPP software
According to Vancouver, sun buildings are the main source of greenhouse in Vancouver. Detached houses took the line share from this emission. The worst culprits are single-family houses. Let me show you where the energy goes by percentage:
- 60 % heating
- 20 % Hot water
- 15% Appliances
- 5 % Lighting
Research shows, the Human body is comfortable in a house with the following thermal parameters
- Air temperature in a house between 20 – 25 degree Celsius
- Surface temperature less than 17 Degree Celsius
- Local temperature varies less than 3 degree Celsius Horizontally and 2 degree Celsius Vertically
- Air tightness – 0.6 ACHRelative humidity 30 – 60 %.
The above parameters can be achieved through:
- Efficient and continuous insulation
- Continuous air barrier
- Avoid thermal bridging
- High-performance glazing ( Windows)Heat recovery ventilation ( HRV)Careful planning
The above parameters can differentiate houses in different energy efficacy category. I will continue my writing about each parameter in my next blog post. Until then, good day.
Yared Demeke is the owner of Alair Homes Vancouver and Alair Homes Surrey. Yared is a certified Passive House Trades Person (CPHTP) from Passive House International (PHI). Yared is certified from BCIT in BC building codes, he has Bachelor’s Degree in Engineering and more than 22 years in commercial and residential construction. You can reach Yared at – 604 290 7272 or by e-mail – [email protected]