Personal Risk Assessment

We all do risk management intuitively – when we decide on uploading our data to the cloud where the NSA may spy on us. Or when we install heating systems that depend on electrical energy. The previous post triggered an interesting discussion about the risk of a power outage.

Is it more risky to pick a heat pump – compared to other systems?

In Austria, nearly all private homes use central heating systems and thus rely on circulation pumps – no matter if you run a natural gas boiler, a wood pellet burner, or a heat pump. Heat is distributed via hot water, powering floor loops or radiators. Heating circuits powered by gravity only are hardly installed today. So a heat pump system does not score worse in case of a power outage. It might hurt even more if you have a cellar full of wood pellets or a tank full of fuel oil – but you cannot get the fuel or the heat to the place where you need it.

You might also compare heaters of the same level of convenience – heat pumps would compete with natural gas boilers that don’t require storage facilities for fuel but access to a grid. I am concerned about gas pipelines traversing countries that make headlines periodically because of the next political gas crisis. But I am less concerned about electrical power – this is the view from our office:

Wind turbines seen from the office

In Austria the average power outage per utility customer and year is less than 1 hour. We had an outage of about half an hour every few years. There are no issues with cable nibbling squirrels, and we worry more about hackers attacking the grid than about breakdowns.

But experts in disaster management tell us that we rely too much on highly available power. This is called the Vulnerability Paradox: The more dependable a service is, the less prepared you are for outages. According to a recent study anarchy will reign a few days after a large-scale blackout in Germany: Police would not be able to refuel their cars as modern gasoline pumps don’t work without power. Sewage systems and toilets would not work.

The impact of ‘just’ not being able to heat might be less dramatic. The lowest average daily ambient temperature here, in Eastern Austrian lowlands, is -12°C. We have encountered it on 4 days in 20 years; the lowest minimum was -17,8°C. If power would be cut off for a day in winter the temperature will fall by a few degrees only. It might irk me more if our internet connection is down for this period of time.

And many Austrian home owners have a backup strategy that blends with aesthetic preferences. Artisanal tiled stoves are popular here:

GrundKachelofenLocal building code demanded us to have an emergency chimney – so we installed the Free Flow Bullerjan stove shown below. I learned now from the company history that it had been invented in Vermont and built in Canada before it became a viral hit in Europe. It can heat our 110m2 open space second storey just fine:

Bullerjan stove

Now why not using a traditional stove for each room as the only heating system – to be independent from the grid all the time? If nobody is at home for several days to put wood on the fire the house will cool off. This is not only a risk, but it will happen with 100% probability, e.g. if you travel for business often.

What happens if power is cut off for several days – and we are traveling? I think the probability would be lower than the likelihood of a tractor crashing into the wall of our house – which is actually a risk listed in our home insurance contract.


Heating 2003 to 2012 by fuels used and heating system (in Austria). Less than 15% of (primary) heating systems are stoves, and they have been on a decline in the last decade. (Link got broken, fixed with new link: 2015-06-04)


7 thoughts on “Personal Risk Assessment

  1. Pingback: Heat Pump System Data: Three Seasons 2012 – 2015 | Theory and Practice of Trying to Combine Just Anything

  2. This is indeed something that is always on my mind. When Joanna and I were in Switzerland we had to switch the house over to the propane furnace. It heats the first floor via forced air, while the second floor heats via convection. When we are home, and both wood stoves are running, the ambient never falls below 65F (18C) while maximum temperatures in the rooms with the stoves (such as the kitchen) can reach 75F (24C)! We have a single thermostat in the living room and we set that to 60 (16C) while we were away. Anyway … while we were gone we had some pretty cold temperatures to right around 0F (-18C), which lasted for a few days. When we arrived back home after 10 days we discovered that a drain pipe from the upstairs bathroom had FROZEN! Drain pipes aren’t supposed to freeze! If a supply line had frozen, I could have understood … but a drain line! It probably had a constriction and was draining slow enough to freeze in the crawl space below the first floor. Anyway, it took us two days to thaw the pipe and get things running again – what a mess. I have never liked our backup heating system. Having said that … I am the first one to brag when the power goes out when we’re home (even in the middle of the winter). We simply fire up the generator and all is well! The Swiss seem to have this power thing figured out just like you do in Austria. My son-in-law reports the 80% of Swiss power is hydro. That’s wonderful. I wish that were the case here in the States.

    • Thanks for sharing this story, Dave!! Yes, freezing pipes was really the worse case scenario I had in mind when writing about leaving the house for a few days. I also wonder how the crawl space could have got that cold. Is there an issue with the insulation of the house? It would be totally interesting to monitor the temperature in that location versus the temperature of the floor above and the ceiling underneath. Or take a photo with an infrared (thermography) camera – maybe the crawl space would be displayed as a blue horizontal line between two warm red areas. The cold space could also increase your fuel consumption and heating costs a lots.
      Older houses can hide some unexpected cold patches – I shared a story in my reply to Michelle. In our case the space where the kitchen is today had been some farm building – very common in the region where I live. Actual homes for a whole family had only 60m2 area in the old days – so when people adapted these buildings later they integrated the attached barns, stables and the like into the ‘main building’. And those outhouses had much thinner walls and ceilings.

      As for Switzerland: It is interesting that they are Europe’s heat pump pioneers. Switzerland is called the country of heat pumps. If I recall correctly 75% of heating systems installed today are heat pumps – given the Swiss geography lots of them have to be located in cold Alpine regions.

  3. When we were on the farm we routinely experienced power outages. One winter was particularly bad, as lines were being upgraded and power was shut off for the maximum allowed time as per local regulations, always without notice, and often as frequent as daily. It brought on the demise of a desk top computer. And it did leave us thinking about heat and power. The house we had was VERY poorly built, and ALWAYS cold even when the furnace ran at 100%. Conservation goes a long way…. and might explain my current fascination with intense insulating practices (I was in the attic again on the weekend, fixing a cold spot).

    • I can relate, Michelle! We had also found interesting cold spots when renovating the house! The kitchen was obviously a converted farm building as the dimensions of ceiling and walls were all different. Much thinner actually. We only noticed it after clearing tons of old straw and the like from the attic, from the space above the kitchen. In the next winter we had the all-time-high in gas consumption – so we had removed the organic insulation of that part of the building 🙂

  4. Funny you should mention that. Last winter was a particularly cold one. This, coupled with inadequate maintenance of the nearby oil-fired generator (a provincial disgrace if you ask me. NL is a province where wind and hydro are super plentiful) resulted in capacity issues that eventually tripped a main breaker and resulted in the failure of one of the three turbines in that oil fired plant. During the coldest part of the winter my province was subject to what became known in social media as #darkNL. It’s case that nicely illustrates what you said–we have become so dependent on cheap electricity that we began taking it for granted.
    It’s worth noting, mind you that since then an additional 100 MW generator was added this past year to supplement the existing three 150 MW devices so hopefully we won’t get the capacity issues.
    In a few years an under-construction project of around 850 MW will replace that thermal station, hopefully.
    But it illustrates nicely what can go wrong when people don’t take risk management as seriously as they should and, instead allow themselves to be blinded by the so called ‘;facts of the day.”
    On an ending note one thing that floors me here in NL is the fact that nobody in authority is really looking at the alternatives and crafting strategies and policies to “green us up.” No serious projects are underway except for the aforementioned hydro one, even though there’s loads of possibilities. Furthermore the majority of the heating systems in place here are “dumb” ones, that is, ones that generate heat directly (baseboard electric heaters and oil-fired furnaces) rather than recovering it from convenient heat sinks, as is the case with your system.

    • Thanks for sharing this information, Maurice – of course I immediately googled for #darkNL. I am always interested in real-live examples. Wow – decades old infrastructure that has reached end of life (according to this article: – so this was not event a black swan like cascade of unfortunate events but something that should be easy to evaluate and add to a list of risks.

      In the last period of several really cold days in a row in February 2012 meeting power demands was an issue in Germany and Austria – but in this case it was also the intricate entanglement of the power grid and the electricity market. Some commentators said that people betting on prices neary caused a blackout, the German regulator phrased it very cautiously – it seemed prices and this forecasts of supply and demand did not meet true demands and thus too much electricity was exported to other countries. If financial markets and trading frenzy is added on top of the technical challenges to manage the power grid – I get really worried.

      Yes – heating with electrical power 1:1 converted to heat does really hurt if you could have a heat pump multiply that eletrical input by a factor 😉 AFAIK this is common in countries that heavily use nuclear power such as France. If you take into account the losses in thermal generators for power you would actually need a heat pump to compensate for them – in Germany heat pumps need to have a performance coefficient of 3 minimum for that reason (Germany has much more thermal power plants than Austria)

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