What’s a passive house anyway?
If you don’t know what a ‘Passive House’ is you’re in good company, most people haven’t. Passive Houses are essentially buildings which use very little energy for heating and cooling, whilst also providing a high level of comfort. If I were to describe Passive Houses in a few words it would be ‘Exceptionally energy efficient, virtually airtight houses’. The houses are so energy efficient they can save up to 90% in heating costs. One of the main focal points of Passive Houses is minimizing air leakage from the property. In fact, for a house to be certified, ‘the building must not leak more air than 0.6 times the house volume per hour’. The houses implement the latest in insulation technology, triple-glazed windows, balanced energy recovery ventilation and limiting thermal bridging, being heated mostly using ‘passive’ energy from electrical equipment, people and passive solar gains.The concept of Passive Houses (‘Passivhaus’ in German) was pioneered by Bo Adamson of Lund University, Sweden, and Wolfgang Feist of the Institute for Housing and the Environment, Germany. The Passivhaus Institute has created a set of quality criteria a household must meet in order for the building to be officially labelled a Passivhaus. The property will then be tested and officially certified if it meets the exact quality assurances necessary. There are 15 to 20 thousand of these houses in the world at the moment and below is a breakdown of what it’s all about and thus, the reasons why the future will be engulfed by this trend and why it makes sense to engineer something similar and jump on the green bandwagon yourselves.
1. The Global Trend is to Reduce Carbon Emissions
It’s been growing in momentum for years; and with huge financial backings and government propaganda (cross out) promotion. Whether you believe global warming or not, or whether you believe climate change is influenced by humans (carbon emissions), it doesn’t matter. A huge juggernaut, a new religion one might say, has started moving and it will take something massive to change the momentum it has.When the G8 met in 2009 to discuss global emission cuts, they set the target to slash global emissions 80% by 2050. India and China did not agree to this as it would mean stifling their economic growth. According to the U.S. Energy Information Administration buildings can account for 48% of annual greenhouse gas emissions; that’s nearly half of total emission production. Most people look at vehicles on the road and factories billowing smoke, yet do not think that what they do in their own homes has a significant impact; well, it does.
So what does this mean for Passivhaus’s?
Let’s look at this logically. The pioneering governments of the world have set goals to cut emissions by 80%: Buildings account for 48% of emissions. It’s glaringly obvious that there is going to be a bigger push in the future for homes which are far more efficient and conserve energy.Whilst walking down O’Connell street in Dublin last night with a Scandinavian friend of mine, she posed the question, ‘Why are buildings in Ireland so inefficient compared to Scandinavia’?. I continued to spew out reasons such as, ‘Temperatures in Scandinavia can be much lower than here in Ireland, therefore there is probably a tipping point, where it makes economical sense to shoulder the hefty one time costs of insulation compared to an electricity bill which’ll be higher, month on month.’. Not convinced by my answer, she responded, ‘Why is then that new builds, such as the apartment which I’m living in are so cold and poorly insulated then?’. I could only put that down to the building contractors providing a property which people would be happy with the quality, compared to what else is available in the market, as the builder wants to turn the property as fast as possible with the highest profit margins possible. They are not going to lose any sleep (with their heads on a pillow of money) over building a property that isn’t on the cutting edge of energy conservation.
2. Future New Builds Will be More Energy Efficient
What’s the solution to this problem we have here (in the U.K. and Ireland at least)? To force change, building regulation standards have to change. With the aforementioned thought of 80% emissions reduction target, 48% of which is caused by property: The logical future step will be a drastic overhaul in new building regulation energy conservation standards. Passivhaus standards are what the government’s needs to meet their targets and the institute is perfectly poised on the crest of a property conservation wave which could take the world by storm. This trend has already started to move, which can be seen here.
3. Future Existing Properties will be Upgraded to becomes More Energy Efficient
The more the government promotes energy efficient houses and educates the public to the facts, coupled with new builds being forced to conform to new energy efficiency standards, we could see a new trend in an enlightened public improving the energy efficiency of their homes. I think this is a two fold effect. Firstly, social psychology towards being green and doing their part will help with the momentum of the trend. Secondly, in my opinion, if new builds are forced to conform to strict energy efficient guidelines it will mean there will be there properties being sold on the market. If these houses aren’t too dear compared to a house which hasn’t been influenced by a Passivhaus standard, it’s clear the choice for buyers will be the energy efficient house. Therefore, to compete with the energy efficient houses on the market, sellers might feel the pinch and feel the need to improve the efficiency of their property.
4. Nearly Off the Power Grid
Saving up to 90% on energy means most of the energy required to run the appliances in the house can be operated by off the grid power, from on house solar panels or on site wind turbines. I’m sure this is especially appealing to the apocalyptic minded of those amongst us!But on a serious note, the reduction in energy consumption coupled with the use of renewable energy sources means the owner of the Passivhaus will be relying upon and using far less fossil fuels such as natural gas, oil, coal and nuclear power.
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5. Consciousness and Conscience
Similar to voting, most people think, ‘What can I do to change the country?’. True, one Passivhaus is like a drop in the ocean of the approximate 1,500,000,000 (1.5 billion) houses in the world and does not seem significant, but what if the trend caught on. The 20,000 could double again and again, then before we know it, we have a noticeable proportion of the world doing their part. Edmund Burke said all that is necessary for the triumph of evil is that good men do nothing.All people have problems in their lives, and the quality of ones life is determined by the quality of their problems and how they deal with it. Global emissions is a corporate problem which we all have a hand in, therefore as more people are enlightened to it, the more people will feel they are called to tackle the problem and do their part. Some people will feel a tickle in their conscience and will buy a Passivhaus. Don’t be ‘THAT’ person who does nothing.
6. Social Recognition
So much in life can be explained in social psychology. Why do people do what they do and what is it that people truly want in life. From what I’ve seen and have read from the top thinkers in the world, nearly all people crave to be accepted, appreciated and they desire the feeling of importance. What feelings will the owners of a Passivhaus experience? Will they experience acceptance? I certainly feel they would immediately be accepted into the social circles of all those who appreciate architecture and anything green. Will they experience appreciation? I would think most people, even though they might not express it outwardly would at least have some appreciation and admiration for what that person is doing for planet earth. Will they feel important. I think that importance would materialize in oneself from sowing seeds of goodness into something much bigger and long lasting than oneself: Planet earth.I don’t think I’ve really given the best argument here, but I feel there are seeds of truth entwined within. Worst case scenario, having a Passive House is a great conversation piece, especially when one has visitors around to the house.
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7. It Saves you Money
In the long run it does anyway! Initial outlay will be significant but it’s just a matter of simple mathematics: (Initial outlay for property improvements / energy saving per month = Time it will take for investment to pay itself back). Like I mentioned in the beginning, one could cut the cost of their energy bill by 90%. I read on one website that their Passivhaus designs could cut a $1500 energy bill to $100 per year; which is even better than 90%. This will appeal to those who are planning on living in the same house for years to come, or feel their house will be more desirable upon sale and could recoup the investment in the sale cost.
8. Improved Air
When talking to people about how Passive Houses stop air leakage they tend to comment on how the ventilation system must be very good in order to breathe. They presume the quality of air must be lesser than a normal home but in reality it’s the opposite. With the sophisticated air circulation system, the air which is ventilated into the home is filtered and is efficiently warmed, with the old air being exhausted out. The sophisticated ventilation system controls the humidity within the house between 30 and 60%, replacing that stale, sticky atmosphere with one that feels fresh and clean. The air is ventilated, warmed and circulated using a heat recovery ventilator which can be seen in the diagram below.
9. Government Tax Credits and Grants
In some states in the U.S.A. and various other countries in the world it is currently possible to receive a tax break / credits, or even a grant if you install energy saving materials and equipment into your home. There are also schemes which offer low interest rates for those using the loan to buy energy saving materials for the home. I believe this trend will continue and will mature in their appeal to the general public as the years pass and the governments of the world realise they are significantly lagging in their low emissions targets.
What keeps warmth in keeps sound out. The thick insulation on the walls and the high performance triple-glazed windows means you can make noise and not disturb the neighbours and the neighbours would have to do something miraculous to disturb you. Passive Houses could be a potential answer to houses which are built in the part of airplanes.
11. Comfortable Housing
That’s what we all want isn’t it; a house that is comfortable, relaxing and pleasant to be in. That’s exactly what the Passivhaus boasts that it is. The main thrust of the notion of comfort in Passivhaus is ‘thermal comfort’, however the follows at the Passivhaus institute are so serious about comfort that they have created an Fangers equation which takes into account air temperature, temperature of surrounding objects (radiant temperature), air speed and the humidity of the air. Sounds comfortable doesn’t it! I like this level of detail, and it’s this detail that tells me a Passivhaus would be a great place to live.
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12. Long Lasting Quality
The first Passivhaus was built 23 years ago in 1990 and it’s still running like new. To achieve the stringent quality guidelines a house must adhere to obtain a certificate from the Passivhaus Institute, the highest quality material have to be used, and it’s in these materials which creates durability. Buy quality, buy once; buy cheap, be prepared to buy twice or thrice.
Last but not least, I forecast the cost of Passive Houses to drop. Currently (as of 2009) a Passivhaus equivalent would cost approximately $190 per square foot, compared to $85 to $120 for most houses. Economics tells me that the more of something that is made, the price of that product will come down through economies of scale and increased competition. I hope that as the quantity of Passivhaus’s drastically increases, the price of the materials used will drop accordingly, making Passivhaus practices an easy choice in the future for homeowners and property developers alike.I’m certainly a convert: Are you?
Technical Details of Passive Homes
The minimum standards of a passive house building in Europe are as follows:
- ‘The building must be designed to have an annual heating demand as calculated with the Passivhaus Planning Package of not more than 15 kWh/m² per year (4746 btu/ft² per year) in heating and 15 kWh/m² per year cooling energy OR to be designed with a peak heat load of 10W/m²
- Total primary energy (source energy for electricity and etc.) consumption (primary energy for heating, hot water and electricity) must not be more than 120 kWh/m² per year (3.79 × 104 btu/ft² per year)
- The building must not leak more air than 0.6 times the house volume per hour (n50 ? 0.6 / hour) at 50 Pa (N/m²) as tested by a blower door’