December 27, 2008
Passive House Design Takes Off In Germany
The idea of extremely well insulated houses which need little heating is not a new one. But advances in design made at an institute in Darmstadt Germany are making so-called passive houses more practical. A New York Times article takes a look at the growing popularity of passive house designs for heating.
The concept of the passive house, pioneered in this city of 140,000 outside Frankfurt, approaches the challenge from a different angle. Using ultrathick insulation and complex doors and windows, the architect engineers a home encased in an airtight shell, so that barely any heat escapes and barely any cold seeps in. That means a passive house can be warmed not only by the sun, but also by the heat from appliances and even from occupants’ bodies.
And in Germany, passive houses cost only about 5 to 7 percent more to build than conventional houses.
The article reports higher costs in the US because some of the special windows and other supplies are harder to come by here.
This is still a pretty small scale phenomenon with only 15,000 passive houses built so far - most in northern European countries.
“The myth before was that to be warm you had to have heating. Our goal is to create a warm house without energy demand,” said Wolfgang Hasper, an engineer at the Passivhaus Institut in Darmstadt. “This is not about wearing thick pullovers, turning the thermostat down and putting up with drafts. It’s about being comfortable with less energy input, and we do this by recycling heating.”
There are now an estimated 15,000 passive houses around the world, the vast majority built in the past few years in German-speaking countries or Scandinavia.
You can't build this sort of house on a north-facing hillside or in a city street with a skyscraper shading your property. The development of this technology for cooling is nowhere near as far along.
I like this idea because it reduces our vulnerability to disruptions in energy flows in an industrial society. Loss of electric power doesn't mean a freezing house. The use of wood heating for this purpose doesn't scale as well due to limited supplies of trees. Also, putting wood on the fire is a chore and the resulting smoke isn't good for health.
Passive houses also reduce usage of limited supplies of fossil fuels, reducing pollution in the process as well as saving money in the long run.
Whatever happened to hydrogen fuel cells for residential and light commercial power generation applications? In the late 90's these things were being trotted out by GE, Plug Power, Ballard et al. in 7 to 9kw home application that ran on natgas. GE apparently gave up, Plug is still struggling.
Like lots of green "solutions" with no results, does it bother you that, for now, marketing to rich phonies is all this stuff really is?
Nice idea except:
Animal dander, Dust mites, pollen
Household chemical fumes
Airorne lead & Mercury vapors
Radon & of course the most insidious invisible toxic killer...CO2
If increased exposure to the above is the price for saving energy....I'll continue my profligance
These highly air-tight houses typically have air exchangers that minimize heat loss. I presume the passive house designs do this as well. This suggests maybe a fan is needed to keep the house safe if the windows are kept closed. But maybe they use some passive mechanism for the air exchange. Don't know.
In the 70s and 80s office buildings were built 'sealed' in an attempt to save energy (a primitive precusor to this passive house concept, I surmise), and the result was the rise of 'sick building syndrome', precisely the sort of thing that JoeKing is refering to. Perhaps we have learned from those experiences, but I haven't seen anything to indicate that we have, and given the way that the concept is being implemented, I am not sure that many of the problems can be dealt with effectively...
All of this for 5-7% decrease in energy costs? I know that those costs aren't peanuts, but there are other, far less problematic solutions out there...
A brand new house for everyone. What problem are we trying to solve by spending that kind of money?
If solar, and wind don't work out, there is always coal.
You live in a house like that, you gotta not eat beans.
On closer inspection they seem to have a handle on the air quality issue thru the use of an air-exchanger; however ther are other problems.
1..Very limited architectural freedom of design...pretty much a square bunker
2...There are no heating zones, thus the home will have only 1 temperature...they state usually 59 degrees; which leads to bigger problems
3...59 degrees (with low humidity) is about 10+ degrees below the typical American's winter home temperature. While this might be acceptable to tough German we American wimps will NEVER accept such Spartan conditions. The last & real deal breaker..
4...Health effects of such low temps will cause increased respiratory illnesses & premature DEATHS to vulnerable populations (Asthma sufferers, elderly, infants etc).
Like th said, these will be marketed to "rich phonies" & have you ever met one who would actually be UNCOMFORTABLE to be green...me neither.
I would expect one could use a conventional heater to lift the temperature from 59F to something more reasonable. The ability to count on the 59F point as the starting point will reduce the total amount of energy needed for heating.
I think with a more active system one could achieve a greater level of insulation when the sun is not shining. Either pull insulating layers across the windows when the light falls below some insolation level or collect the heat via an external layer that is black in the back and with glass in the front - kinda like a solar water heater. Then heavily insulate.
I would think that large glass areas really limit how much insulation efficiency can be achieved. We need a way to let thru more sunlight while achieving a much higher level of insulation. Vacuum might do the trick but would require very strong glass and sealing.
Yes these houses are efficiently ventilated. Cool air does not cool the structures because airs heat capacity is low.
The construction of passive- and low energy houses is increasing rapidly hear in Finland. We have cold winters anyways and quite a lot of insulation around the house. So the leap to passive house is not that big. And it's mostly middle class income families (and communities+corporations) who build these houses. Not just rich folks. Electricity is quite expensive around here and even more so in Germany (because they don't want to use nuclear power). So in time the savings can also be monetary and not just energy when building passive or low energy houses.
And the temperature is usually kept around 20-22 celsius degrees.
I would expect one could use a conventional heater to lift the temperature from 59F to something more reasonable.
I think you are chasing your tail here....they are either passive homes or they aren't. Just adding a conventional heater can't be just thrown in & voi-la you have a comfortably heated 70 degree home. You still haven't addressed the multi-zones which we have become accustomed too. I also don't think the ventilation from kitchens/bathrooms will handle American needs with their 1200cfm hoods over their 6-burner/charbroilers Viking ranges & 5 bathrooms with hot tubs.
There are I believe something like 100m housing units in US. I really doubt a few thousand (hundred?) homes like these will be any great safety net from future energy supply disruptions.
My basic philosophical problem with "miracle" solutions like this to the "energy crisis" is first, the crisis is overstated & secondly, the general public isn't going too, in mass, leave their comfortable homes for expensive, quirky high-maintenance new homes which have a 20-50yr. payback...just because its ecological; & if large numbers DON'T participate the overall effect on the "crisis" is negligable.
I see these as little more than professionally built "earth ships"...old age homes for hippies.
Lets throw the baby out with the bath water, shall we. I have a multi-zone home, but it is not by choice. My father, Uncle, and Grandfather built this house when (in the 30's) gas heat was penny's. There are thousands of houses like mine that people live in and have to bear the brunt of energy costs. Those who live in these multi-zone, 6 burner/indoor bbq, with six fireplaces (and in the winter with fireplaces burning, auto-slamming exterior doors) I'm sure will be glad to pay for the energy they use. It will be the new arrogant status symbol of the near upper middle class. Passive homes, just like regular homes, have been a science in progress. Just like Solar, things get better.
Solar array panels and wind generators are way out of the common man's price range, and the payback period is unrealistically long.
Passive house technology is a fascinating concept my husband and I are exploring for the building model of our future home.
Indoor air quality is a big issue and we think can be handled by adequate ventilation systems. We need to figure out how to pre-warm the heating air, and building code in most states require a back up heating source.
If these homes are to be LEED or Energy Star certified they will need to pass rigid testing and safety standards.
In our business we see a steadily growing number of energy minded people looking to build and rehab with energy efficiency and sustainability in mind.
We remain hopeful this idea will be a viable option for us.
I can't believe that Scott's reading ability is so bad that he thinks a "Passivhaus" only decreases energy demand by 5-7%; the fact is that it has 5-7% more cost for close to a 100% decrease in energy demand. If he's not a troll, where the heck did he come from?
I suspect that a lot of the resistance to things like Passivhaus come from the required changes in building practices (SIP instead of stick-built) and consequent threats to construction interests, whose labor inputs would both be reduced and centralized. Paradoxically, I think this is a good reason to require Passivhaus standards; eliminating most of the semi-skilled on-site labor would make it much harder to hide the employment of illegal aliens.
I have been living in a passive house for five years now in Urbana Illinois. Recently a grad student from the University of Illinois approached me with an interesting proposition: "Would you allow me to test the indoor air quality of your home? I am also testing three other conventional homes". Of course I was in. Result was that my home was the only one meeting the requirements of the EPA. All other homes had most notably too high Radon levels.
The ventilator takes care of all the problems mentioned: it regulates humidity (mold has no chance), transports VOCs and other toxins continually to the outside. In fact, in Germany doctors recommend passive houses for folks with respiratory problems because the indoor air quality can be controlled like in no other building through problem specific filters.
Temperature in a Passive House: it is calculated to 65 Degrees Fahrenheit and you can of course heat the house to where you like it. No idea where the 59 came from, oh maybe, because well insulated houses have warm exterior wall surfaces, therefore lower temperatures are perceived as comfortable. This results in even more energy savings. Trust me, Germans are not tougher than American, they get cold too.
Its just a wonderful home, cost me at most 10% more than a conventional home. Its like living in fresh air all the time, just warm. Zonal heating was invented because existing homes are just so drafty and uncomfortable, not the case with a Passive House.
The 59 degree number came from a loss of all power and with occupants that will be what the house will "steady state" out to but with no power comes the ventilation issue. Perhaps a UPS on the ventilator?
I would surmise that even if you couldn't get a south facing lot that the insulation and ventilation system would work wonders to reducing heating needs and cost. Think of all the oil heat and hydro-carbon burning heating systems that would be displaced as newer houses were built.
If home builders were building these there would be such a run on the new "passive house" idea that it would create a new economic stimulus that this country needs.
The Passive House is a fantastic concept. Those that need "1200cfm hoods over their 6-burner/charbroilers Viking ranges & 5 bathrooms with hot tubs." might not decide to build a passive house. But I would not expect such ignorant gluttons to understand new technology and the benefits it could have on our environment. I can assure you there are more people in this world that are concerned with the environment and energy efficiency, than people that need to heat 5 hot tubs.
With more Passive Houses being built, the technology will only improve. I look forward to the day that the majority of civilization is living in such Eco-friendly homes.
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