No Furnaces but Heat Aplenty in ‘Passive Houses’

[depakid]

Berthold Kaufmann and his wife, Dorte Feierabend, with their daughters in their "passive house" in Darmstadt, Germany
-------------------

From the outside, there is nothing unusual about the stylish new gray and orange row houses in the Kranichstein District, with wreaths on the doors and Christmas lights twinkling through a freezing drizzle. But these houses are part of a revolution in building design: There are no drafts, no cold tile floors, no snuggling under blankets until the furnace kicks in. There is, in fact, no furnace.

In Berthold Kaufmann’s home, there is, to be fair, one radiator for emergency backup in the living room — but it is not in use. Even on the coldest nights in central Germany, Mr. Kaufmann’s new “passive house” and others of this design get all the heat and hot water they need from the amount of energy that would be needed to run a hair dryer.

“You don’t think about temperature — the house just adjusts,” said Mr. Kaufmann, watching his 2-year-old daughter, dressed in a T-shirt, tuck into her sausage in the spacious living room, whose glass doors open to a patio. His new home uses about one-twentieth the heating energy of his parents’ home of roughly the same size, he said.

Architects in many countries, in attempts to meet new energy efficiency standards like the Leadership in Energy and Environmental Design standard in the United States, are designing homes with better insulation and high-efficiency appliances, as well as tapping into alternative sources of power, like solar panels and wind turbines.

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. Decades ago, attempts at creating sealed solar-heated homes failed, because of stagnant air and mold. But new passive houses use an ingenious central ventilation system. The warm air going out passes side by side with clean, cold air coming in, exchanging heat with 90 percent efficiency.

More: http://www.nytimes.com/2008/12/27/world/europe/27house.html?em
----------

Sure beats this "soluton"



http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x180426

[shraby]

1. It looks to me like the German home has

a lot less square footage than the other one. A lot less.

[yodoobo]

3. yea, 500 sq ft per person

Thats pretty tiny.

[salvorhardin]

7. That's not too bad for a family of four

About 2,000 square feet is not too bad for a family of four. Most homes built through the 1950s were in the 1,500 - 2,200 square foot range, concentrating toward the lower end. That's enough for a decent sized living room, dining room/office space, kitchen, two or three nice bedrooms, and a bathroom. My partner's house is 1,800 square feet and has three bedrooms but we both agree that with everyone in the house at once it's too small. Eventually we hope to finish off the basement, along with putting in a half-bath down there, and rec room.

500 square feet is not too awful even for a single person. My apartment is 538 square feet and includes a living room, kitchen, bath, bedroom and utility area (for washer and dryer). Storage space, especially in the kitchen, is at a premium though. Just a few more closets and an extra small room for my office and it'd be perfect for me. I think 700 square feet is just about right for a single person. Of course, others' mileage may vary.

[yodoobo]

8. Now that you put it that way.

yea about 2k is about right for a family of four. Kids definitely take up alot more room than adults I think.

I personally wouldn't want to go below about 1300 sq for 2 people though. Sometimes you need your space :)

I guess it depends on how much "stuff" you got, of which I'm of the mind that most people have to much of.

[salvorhardin]

9. Absolutely, you need your space

It's just that in pre-surburbia, people used to walk to the local pub, club (social club, not dance club), library, park, etc. to get a little "alone" time, or just time socializing with somebody you're not sleeping with and/or feeding every single day. Also, man caves have been around for as long as there have been men. It used to be the garage, basement workshop, VFW, or the aforementioned social club. Witness the proliferation of how-to magazines in the 40s-70s. Guys didn't really take up woodworking because they liked knotty pine -- it was a chance to get away from all the noise, confusion and honey-dos. Now we all hole up in our houses like we're under siege (I'm as guilty of this as anyone, perhaps more so).

[oldnslo]

4. That German couple is sitting in a room that looks to be the same

Size as my home office--about 10x10. Pretty small for a living room, and it doesn't take a lot of heating tech to heat small sq. footage pretty cheaply. Bet it takes awhile to roi, and can't be retreo-fitted to existing homes, obviously.
It will be a while....don't hold your breath, we've got bigger fish to fry over here.

[Atman]

6. That room is small, but it's no 10 x 10.

The perspective of the photo is tricking you. Those doors are wide enough to walk through, and there are two of them. The depth of the room is unknown, unless you're assuming the photographer is squished up against the opposing wall. I think not. Again, it may not be an American-style "great room," (WTF is that, anyway?) but it's not 10 x 10.

.

[salvorhardin]

10. Agreed

The wall with the doors has to be at least 16 feet wide. The sofa looks to have three seats which means it's probably about six feet long and there's probably a minimum of three feet between the end of the sofa and the wall with the doors. My guess is the room is about 12 ft X 16 ft or 192 sq ft. Not huge, but not at all small.

[WePurrsevere]

14. Passive House Retrofit kit...

http://www.energieinstitut.at/Retrofit/?to=0&forward=S_19&id=9a077def8198c9d80685ab247a5e977c&dmy=de64bd0cb6841cc57a990b74c2997ac1

It isn't quite a good as a brand new house built this way but I'd say a savings of 80% to 95% is nothing to sneeze at. :)

My DH and I own a 1776 sq foot house built in 1850 with an addition from the mid 70s and we've been looking into doing something rather similar... using blown in foam insulation (If you're familiar with "Great Stuff" it's basically the same product). Since we live in the North Country it would take less time for us to make back the cost then someone living in warmer climates but the more we learn the more it makes sense to us... now we just need to money to do it all. :)

[yodoobo]

2. Interesting

I wonder if it works the same for cooling?

[Atman]

5. McMansion owners can do this by hooking up a vent to the tailpipes of their Hummers...

...and running into their living rooms.

Seriously, fuggedaboutit. This is America. Here, we'd have talking heads on air all the time saying "We don't want to live in tiny shoe boxes! We need space to avoid our kids and wives!" We've got many, many years of terrible habits to overcome.

.

[salvorhardin]

11. Average home size has gone up dramatically

According to the National Association of Home Builders, the average home size in the United States was 2,330 square feet in 2004, up from 1,400 square feet in 1970.
http://www.infoplease.com/askeds/us-home-size.html

I don't know how accurate that number is, but let's assume it's true. What I'd really like to know is what the median home size is though. I wonder if we're not getting an inaccurate picture of modern home sizes because of a relatively small percentage of homeowners built McMansions in the 90s. I know it seems like they're all over the place, but that's because they stick out like sore thumbs on the landscape and there's probably a fair but of confirmation bias going on.

I agree with you though that our values have become somewhat warped in the last few decades.

[kristopher]

12. FYI US housing: floor space

I don't know about Germany, maybe someone else has access to that information.

Table 2.2.4
Residential Floorspace (Heated Square Feet), as of 2001 (Percent of Total Households)
Floorspace
Fewer than 500 4%
500 to 999 20%
1,000 to 1,499 21%
1,500 to 1,999 16%
2,000 to 2,499 13%
2,500 to 2,999 9%
3,000 to 3,499 6%
3,500 to 4,000 4%
4,000 or more 8%
Total 100%
Note(s): The 2001 average new single-family housing floorspace was 2,324 square feet.


Table 2.2.11 Characteristics of a Typical Single-Family Home
Year Built late 1960s
Occupants 3
Floorspace
Heated Floorspace (SF) 2,047
Cooled Floorspace (SF) 2,061
Garage 2-Car
Stories 1

http://www.btscoredatabook.net/ChapterView.aspx?chap=2#2

This is an outstanding energy database.
http://www.btscoredatabook.net/TableOfContents.aspx

[salvorhardin]

13. That's what I thought...

Average home size doesn't give a good picture of how most Americans live. Almost three quarters (74%) of Americans live in homes that are less than 2,500 square feet. Half of all Americans live in homes that are between 1,000 and 2,499 square feet. And almost a quarter (24%) of all Americans live in homes that are less than 1,000 square feet.

Thanks for the link to that great set of statistics.