Another year passed by: Energy consumption in a passive house

In the first year of living in the new house I kind of read the energy meters more or less weekly, then it turned into bi-weekly to monthly activity. The past year I looked at the meters mostly during the Winter months and almost forgot to read them out last weekend when another year had passed. When you look at the energy consumption, there are surprising numbers:

	2012	2011	2010	2009
Household (kWh)	2597	2605	2473	2244
Heating/Ventilation/Water (kWh)	2713	2713	2858	2782

Even though the past year was a leap year (and had a leap second!!!) the consumption was the same. I had hoped to have a smaller number, but we had some very chilly weeks in February. Household consumption has also stayed constant with most consumers now in place. Most of it should come from cooking, laundry and my home office with computer, monitor, phones, etc.

Our house does not have a smart meter where you can track consumption online and real-time. However, I talked with some "owners" and the bottom line is that after the first few weeks they barely make use of it. It is similar to reading our old-fashioned meters more frequently in the beginning to learn and look for exceptions. Then leaning back once everything seems to run smoothly. Any similarities to a well-tuned database system and regular workloads...?

Energy consumption for another year in our passive house

A third year of keeping the tab of our energy consumption has passed. Luckily, even with changing weather and sometimes frosty days, the kilowatt hours that we used over the past 12 months stayed almost the same. I had reported about the previous year last July. So how what do the energy meters say this year?

• Household consumption: 2605 kWh (2010: 2473 kWh, 2009: 2244 kWh)
• Heating/ventilation/water: 2713 kWh (2010: 2858 kWh, 2009:  2782 kWh)

As you can see, we used slightly more electric energy in our household, but slightly less for heating and ventilation. Our kids are growing and we need to cook more, they stay up longer (needing electric light in the Winter), they started listening to music, etc. (yeah, blame the kids). On the other hand, my home office requires more electricity, but I travel more often which keeps a balance.

Let's see where we stand next year. I would be happy with small changes only as we have seen this year. What is your consumption?

Another year gone by: Energy consumption in our passive house

We had a long and cold Winter in Germany and also several upgrades to our electrical equipment in our passive house. So I was curious how our energy consumption would be for the last 12 months compared to the year before. This morning was the time to read out our two energy meters (still old fashioned and not smart):

• Household consumption: 2473 kWh (previous year 2244 kWh)
• Heating/ventilation/water: 2858 kWh (previous year 2782 kWh)

As mentioned, the Winter was long and cold and thus the small increase for heating makes sense. It would have been even bigger if we would not have "cheated" when we bought (and used) a table-top fireplace. That small fireplace has a nice flame, burns Ethanol and, of course, produces some heat. It's stronger than some candles and only needs about 0.15 l of Ethanol an hour.

For the increased household consumption one big factor is my work: I traveled less over the past 12 months and worked more and longer at home, started using a 2nd screen, and am now using an automatic coffee/espresso maker to keep the spirits high. Now add in some kids asking for more TV and computer time, some more washing cycles, and extended cooking, then the increase for the household is surprisingly small.

Passive Houses in the US

One of the many questions I got regarding our passive house (see the Wikipedia entry for many links) is whether there is a similar standard in the USA or whether I know of resources to learn more about what is available. I promised that in a blog post I would try to list some resources I found and learned about the last few years. Guess what, you just started reading that promised post.

Image via Wikipedia

When my wife and I started to look into building a passive house we - by chance - also heard an interesting radio story on NPR about such a house built out of straw in Southern California and also saw a documentary in the German children TV show "Die Sendung mit der Maus". I found the documentary on youtube:



Although it is in German, you will find several videos in your language, e.g., English, by searching for "passive house".

In Germany, the Passivhaus-Institut is trying to set and coordinate standards, provide help and research technologies. It also offers information in English. In the US there is now a Passive House Institute US. In addition to information material it also has contact data for Certified Passive House Consultants all over the US.

A passive house combines several technologies to reduce energy consumption. So it is a good idea to learn about those components individually:

• solar panels are used to either heat water or to produce power
• ventilation systems with heat recovery are in place to allow constant ventilation while preserving energy in the Winter and helping to keep the inside cooler in the Summer
• in many houses a heat pump is used for heating and warm water
• windows have to be of good quality and should be constructed such that they let sunshine in during the Winter and are covered by shade in the Summer

That's probably already more than I wanted to write in this first installment. Let me know if you have specific questions.

Passive houses, windmills, clouds, ice saints, DB2, and some nice prizes

Well, what a headline! Full of energy and still kind of energy-conscious, full of nature and still kind of technology-centric, serious stuff and still fun. Let me explain...

As most of you probably know, my familiy is living in a passive house (very low energy house). The Winter in Germany has been long and cold and everybody spent a good chunk of money on heating. Everybody? It turns out that even though our entire house was heated throughout the Winter, we only consumed a little bit more than the year before. Yesterday evening I checked the energy meters (still not smart meters) and we are on track on being only less than 5% higher consumption for heating than last year. We will see the result around mid of July.

After some really warm weeks it is cloudy, rainy, windy, and chilly outside. Seems like the so-called ice saints have an early arrival (this is a weather pattern caused by warm land masses and still cold ocean in Northern Europe). Speaking of wind and clouds: Google just invested in windmills and IBM is buying Cast Iron for cloud integration.

What is left? DB2 and the nice prizes. IDUG started a contest "Do you DB2?" where - if you are based in North America - you can win a Wifi-enabled HDTV or an iPad. To win you need to tell your personal DB2 story. Running a DB2 server in a passive house is probably not a good story ("with product X the house keeps warmer than running DB2 because more CPU cyles are burned and more disks are needed for X and hence more heating is produced") or is it? What is your story?

A passive house in Fall / Unser Passivhaus im Herbst

It's Fall again and especially the nights are cooler - outside. While in houses in Germany the heating systems has been wakened up after the long break, our house is still warm inside. And we expect it to be like this without heating for the next month or longer. The thicker walls and better insulated windows protect the inside against the cold (sometimes down to 5-8 C / 40's F) that now is dominating most of the nights. With the Indian Summer in the small forest next doors, it's a time to enjoy the house and the inside temperatures.

Der Herbst ist mittlerweile deutlich spuerbar, zumindest draussen. Die Naechte sind kuehler geworden, zum Teil gehen die Temperaturen schon runter bis 5-8 C. In unserem Haus ist es nachwievor warm, die staerker isolierten Waende und Fenster zeigen nun, was sie koennen. Waehrend in den Haeusern von verschiedenen Verwandten und Bekannten z.T. schon seit ein paar Wochen die Heizung zeitweise ihren Dienst tut, war es bei uns bislang nocht nicht notwendig. Und ich erwarte/hoffe, dass es zumindest den Oktober ueber so auch bleibt. Auch unser Brauchwasser wird noch komplett durch die Solaranlage auf dem Dach erwaermt, was den Geldbeutel freut. Da kann man den bunten Herbstwald direkt nebenan noch mehr geniessen...

Energy Consumption in our Passive House / Jahresstromverbrauch in unserem Passivhaus

[Fuer die deutsche Fassung bitte weiter unten schauen]

Today a year ago we could start with our apples to apples energy metering in our passive house, a low energy house. This morning I went down to our basement to read out the meters, something I typically try to do once a week. So how much electrical energy did we consume over the last 365 days? A total of 5026 kWh. This is less than anticipated. Let me try to put this into perspective and to give you more details.

Our house has ~150 square meters (~1620 sq. ft.) in two levels plus an unheated basement of almost 100 square meters. We are 2 adults and two kids, I am mostly working from home and my wife is domestic engineer (a.k.a. homemaker or stay-at-home mom).

We have two power meters, one for the heating/ventilation system and hot water, another one for the regular household (fridge, freezer, washer, dryer, computers, phones, oven, dishwasher, lights, ...). What is surprising to us is how much we still spend on heating compared to the household consumption:

• Household consumption: 2244 kWh

• Heating/ventilation/water: 2782 kWh

However, after analyzing the fact deeper, we realized that we only have new A+ or A++-rated household appliances and mostly use energy saving bulbs. Moreover, the computers do not use much energy even though they are often running 12+ hours.

For the heating/water part this is within the expected range. From April to October a solar panel is heating up the water. During the winter we try to keep the inside temperature around 22 degrees Celsius (72 degrees Fahrenheit).

I tried to find comparison data and according to some German sources a similar household would spend around 4000-5000 kWh just on the household part. Heating ranges from 8000-25000 kWh alone.


Jahresstromverbrauch in unserem Passivhaus
Vor einem Jahr konnten wir mit unserem Stromverbrauchsmessungen in unserem Passivhaus beginnen, vorher standen noch Bautrockner im Keller. Ueber das letzte Jahr hinweg haben wir 5026 kWh an Strom verbraucht. Der Verbrauch teilt sich auf 2 Zaehler/Bereich auf:

• Haushaltsstrom: 2244 kWh
• Heizung/Lueftung/Warmwasser: 2782 kWh
  

Beim Haushaltsstrom zahlt sich aus, dass wir nach unserem Umzug aus den USA nach Deutschland die meisten Elektrogeraete neu kaufen mussten und somit fast ausschliesslich A+ oder A++-Geraete haben. Der Haushaltsstrom umfasst alles von den Computern (Heimbuero) ueber Telefone bis zu den ueblichen Verbrauchern wie Kuehlschrank, Gefrierschrank, Waschmaschine, Trockner, Backofen, Herd und Spuelmaschine.

Der Heizstrom ist fuer die permanente Lueftung, die Kleinstwaermepumpe und Zusatzheizer sowie die Solarpumpe. Unser Haus hat 150 Quadratmeter an Wohnflaeche, die im Winter auf ca. 22 Grad Celsius gehalten werden.

Setzt man den Gesamtverbrauch in Perspektive zu den Durchschnittswerten in Deutschland, so zeigen sich die Einsparungen durch ein Passivhaus und durch Energiespargeraete. Wir haben neu gebaut und mussten umzugsbedingt auch neue Geraete anschaffen. Ob sich zusaetzliche Daemmung bzw. die Abloesung von Energiefressern durch moderne Geraete lohnen, muss jeder einzelfallbezogen entscheiden. Unsere Werte zeigen jedoch das Potenzial.

Thermal Images have arrived

In a February post I wrote about Thermal Imaging and that it can be considered quality assurance work for your (new) house. Yesterday evening we finally received a binder with several infrared shots of our house (paper only).

The scanned image below shows the West side of our house with the forest in the backdrop. The picture was taken around 10pm when it was around 1 degree Celsius outside. Clearly visible is the roof, the windows, and on the left our porch. You might wonder about the one whitish vertical and the two horizontal lines. We have a prefabricated house and those lines indicate where the large panels have been joined. Energy-wise those joints are the weaker spots. However, in our case the entire house fares very well. QA passed!

One year ago: Moving in

One year ago on a cold Wednesday morning "our" container arrived and we moved in our new passive house. This was after a 7 week journey by truck and train from San Jose, CA, to Houston, TX, then on with the Sealand Motivator to Bremerhaven, Germany, by train to the Ulm (Germany) container terminal and on by truck to Friedrichshafen.


Later that morning during the unloading, a customs inspector arrived for a 30 minute/40 EUR visit to make sure we didn't bring large quantities of Weber grills. We only had US junk bonds... :)

Our kids enjoyed having their toys back and all of us, after 7 weeks in hotels and with relatives, to sleep in our own beds again.

Spring has arrived (no Java inside!)

Spring is finally here! For those of us who are too deep in software I want to emphasize that it is NOT Java-related, it is the season and Wikipedia has this:

The phenological definition of spring relates to indicators, the blossoming of a range of plant species, and the activities of animals, or the special smell of soil that has reached the temperature for micro flora to flourish. The first swallow to arrive for the flowering of lilac may be the indicator of spring. It therefore varies according to the climate and according to the specific weather of a particular year.

What is not mentioned in the Wikipedia article is that it is a very nice part of a year when living in a passive house. The Winter has been cloudy and foggy here in the Lake of Constance region, but now the sun is shining and both warming our house and the water. The solar panel on our roof is getting enough hours in sun light to heat up the entire water tank, and also inside the house it is nice and warm without a heating system.

What else is missing in the Wikipedia article? Both our local Zeppelin here in Friedrichshafen as well as the one in the San Francisco area are starting passenger flights again. It's nice to see the Zeppelin overhead, tourist season is coming.

Finally, Spring is also linked to Spring cleaning. There seems to be a complete checklist of what to do during Spring cleaning. I just checked and I couldn't find upgrading to DB2 9.5 on it. One more important thing to consider for the coming days...

Passive House & "Arctic" Wheather / Ein Passivhaus bei den arktischen Temperaturen

Right now it is freezing cold in Germany (up to -18 Celsius last night), in our region we had "moderate" -12 degrees Celsius last night. How are the temperatures inside a passive house at this time, given that we only have a small heating system?
The thick insulation and walls fight off most of the cold and let the warm air stay inside. To have fresh air inside and keep it warm inside, our ventilation system follows the following steps:

• Fresh air is received through an earth tube (a 40 m long pipe buried 2 m deep) which causes the air to warm up from the -12 C to around 7 C.
• A heat exchanger takes the energy off the out-flowing air and warms up the in-flowing air. This brings the in-flowing air to already 19 C.
  
• Over night the 400W heat pump bumped up the in-flowing air temperature further to around 30 C.
• Throughout the day we had clear skies and the sun helped to keep the inside temperature at 23 C (kids were wearing T-shirts only), without the heating system on.

To summarize, it was nice and warm inside, really cold outside, and we had minimal energy consumption.

Passivhaus-Temperaturen bei "arktischem" Wetter
Derzeit ist es richtig eisig draussen, bei uns war es "nur" -12 C letzte Nacht. Wie sind die Temperaturen in unserem Passivhaus? Recht angenehm kann man sagen. Dies haengt damit zusammen, dass die dicken Waende die Kaelte draussen und die Waerme drinlassen. Unsere Fenster haben wir Dank der Lueftungsanlage das letzte Mal im Oktober geoeffnet. Jetzt beim kalten Wetter sind folgende Temperaturen beim Prozess des Lueftens festzustellen:

• Draussen sind es -12 C. Die Luft wird durch einen Erdwaermetauscher, ein ca. 40 m langes und 2m tief vergrabenes Rohr, angesaugt und erwaermt sich bis auf ca. 6-7 C.
• Die Luft wird dann durch einen Waermetauscher geleitet, der mit der Fortluft die einstroemendes Frischluft erwaermt. Dies bringt die Frischluft schon fast auf Raumtemperatur.
• Unsere Mini-Waermepumpe (Leistung cal 400W) erwaermt die Luft weiter auf 29-32 C.
• Am gestrigen Tag hatten wir einen klaren, wolkenlosen Himmel mit viel Sonne. Dadurch war die Heizung nicht notwendig und die Sonne half die Temperaturen im Haus auf 23 C zu bringen.
  

Insgesamt ist es derzeit sehr angenehm im Haus, auch was den Stromverbrauch betrifft.

Thermal Imaging - QA work for your house

This morning we were supposed to have a thermal imaging company take pictures of our house (Original source Passivhaus Institut, Germany – http://www.passiv.de, for more examples see here). The idea is to be sure the house was built according to specs and there are no thermal bridges. This is similar to following your quality plan in software development. A thermal bridge can be compared to a memory leak - there are small ones and big ones. In a passive house you usually can find big "memory leaks" yourself because the inside wall would be cold in the winter. Smaller leaks are hard to find and many of them can add up to some energy loss.

Anyway, the sun was already out and had warmed up two sides of the house, so the imaging didn't make sense. Now it's back to waiting for another appointment to come up. On the bright side the thermal imaging guy let me look at our house and I couldn't spot anything concerning. It's also interesting to see your house, mostly colored in blue (good sign).

BTW: It would be nice to have a thermal camera for software products. Take a snapshot and you have most (all?) leaks.

Die Kraft der Kerzen / Candles in no wind

Als wir noch in Kalifornien wohnten, hoerten wir im Radio eine Reportage ueber ein Frau in Suedkalifornien. Sie hatte sich ein Haus aus (ueberwiegend) Strohballen gebaut. Im Sommer war es angenehm kuehl, im Winter angenehm warm. Wurde es trotz Mini-Heizung zu kalt, hat sie im Ofen Kekse gebacken.
Wir nutzen die nachweihnachtliche Zeit, um unseren Kerzenbestand zu reduzieren und damit die Temperatur im Haus anzuheben. 4 Kerzen lassen ueber eine Stunde hinweg die Temperatur im Bereich Kueche/Ess- und Wohnzimmer um 0.5 Grad steigen. Obwohl wir durch die Lueftungsanlange einen konstanten Luftstrom haben, flackern die Kerzen nicht. In Kalifornien flackerten die Kerzen bereits ohne das die Heizung eingeschaltet war (Dank undichter Waende und Fenster)...

We use our still big collection of candles to "heat" our living room (still post-christmas time). Burning 4 candles over 1 hour helped to increase the room temperature by 0.5 degrees. Not bad at all. What was interesting to watch was that they didn't flicker, even with the ventilation system on. In our California apartments candles were already flickering when the heating system wasn't turned on, caused by the lack of construction quality.

How to start a blog...?

"It was a cold and icy night in southern Germany..." are good words to describe what's going on outside (-10 degrees Celsius). Inside our passive house it is relatively warm (21 degrees). Yesterday has been a sunny day, bringing up the indoor temperatures and our mood. Right now I am in my small home office, taking a break from looking over DB2 pureXML code and working on product improvements. The vacation has been shorter than expected, but it was good to relax a little bit from traveling Europe to bring pureXML to IBM customers. It was the first real time out after moving from the US to Germany in March.

I hope that moving forward I have enough time to write about work and life. Enjoy.

For the German audience:
Wie soll mein ein Blog beginnen? Schreibt man ueber die amerikanische Tastatur und die Probleme mit den deutschen Umlauten? Ueber das Klima im Passivhaus bei den gerade vorherrschenden eisigen Temperaturen in Deutschland (ja, ich vermisse Kalifornien ein wenig)? Oder wie DB2 pureXML bei Kunden eingesetzt wird und was es an Neuerungen gibt? Ich werde versuchen, von alldem in der Zukunft zu schreiben, nicht aber mit dem ersten Eintrag.

Fuer die Zukunft ein hoffentlich gutes Lesen.