Isolatie

I’ve been putting it off for two years now but everytime there was a (good) excuse to postpone it again. In 2009 my employer went bankrupt, and in 2010 we got married and our house’s roof needed a renovation. Now the 2011 heating season started and I’m once again confronted with the fact that we;re still burning fossil natural gas to heat our home.

So today I deliberately started the process to finally have our home insulated. I created a letter or flyer in which I invite the people in our block of (eight) houses to an information evening about home insulation. I hope that I can collect a number of households that collectively have their homes insulated at a nice discount.

Depending on the response to the letter I’ll expand the area in which I distribute the letter, because more households should mean a higher discount.

I think I’ll wait about a week and a half for all responses, and then make the decision to expand the distribution area. Exciting!

A passive house schematic

Last weekend many Dutch occupants of passive houses held an open door day to show the world what a passive house is and what it means to live in one. I had a good idea of the concept of the passive house but I had never actually seen one. The open door day was a great opportunity to find out more about the concept.

A passive house is a house that’s insulate so well that in most cases a heating system is not necessary, and when it is necessary, it can be a very small one. In general a passive house features the following properties:

• The roof, walls and floors are insulated extremely well (30-50cm).
• All windows have triple-paned glass.
• It is 100% air-tight, during the building process all gaps were taped.
• There are no thermal bridges between the outside shells and the inside.
• It features a balanced ventilation system with heat recovery.
• It has sun shades of some description on the sun side, because otherwise the house would heat up too much in the summer.

Often (but not always) passive houses also feature:

• A large thermal mass within the insulation shell (usually concrete or stone, sometimes water). Because of this the temperature in the house is very stable.
• A solar hot water system for tap water and/or house heating purposes.
• If a heating system is present, it’s usually a heat pump.
• Because a passive house is very energy efficient solar panels (producing electricity) are often installed, making is very easy to create an energy neutral house – if the solar panels fully cover the occupant’s electricity consumption.

Because the passive house concept starts with the premiss that it’s important to first reduce the energy demand for heating to the absolute minimum before active technical means are deployed this seems a very sustainable concept to me.

The passive house I visited last Saturday

The passive house in Utrecht I visited last Saturday was built by the occupants. This (Dutch) article has more information on the house.

Although I’m not a big fan of most modern building styles this is a nice, big house and as soon as I entered I noticed a few things. The inside of the house is not only thermally decoupled from the outside, but also acoustically. This means that it’s very quiet indoors. This isn’t very noticeable at first, but as soon as a window or outside door is opened some traffic noise becomes noticeable. It’s striking how constant the temperature is throughout the house. It’s slightly cooler at the top floors because less people are present there, but the difference was minimal.

The heating system had not been switched on since the beginning of 2011 (!) and the temperature was still 20,5 degrees. The heating system is a open well heat pump which upgrades the soil’s temperature (10-12) degrees to 30-40 degrees which can be used to heat the house through a hydronic floor heating system. This heat pump also provides hot tap water.

After having seen a passive house I’m convinced that this is the way forward. A basic passive house can be of very simple design without many complex installations. The most complex part of a simple passive house will be the balanced ventilation system and that’s quite simple, really. Depending on the wishes of the occupants the system can be extended with a solar hot water system, a heat pump and or solar panels – but it’s not mandatory. Potentially, any shape is possible from modern to classic.

See for more information on passive houses:

http://passiefhuis.nl/

http://en.wikipedia.org/wiki/Passive_house

http://www.passiv.de/

http://passipedia.passiv.de/passipedia_en/start

The Wattcher display

My employer gave a number of employees a Wattcher on loan so that they can analyse and possibly reduce their electricity consumption. In combination with a website where the employees can compare their consumption statistics they set up a sort of contest who can save the most energy. For the coming few weeks I have one of those devices.

The Wattcher is a nifty device which shows the electricity consumption of a house at a glance. The system consists of two parts:

1. A sensor on the electricity meter which measures the current electricity consumption. This value is wirelessly transmitted to the display.
2. The display, which can be placed in any wall outlet within ten or fifteen metres from the sensor and which continuously displays the current total electricity consumption of the house.  If an electrical device is switched on the indicated consumption will rise and if one is switched off it will fall.

The sensor has a light-sensitive cell which, in case of an electromechanical electricity meter, counts how often the black tab passes. In case of a digital meter, the cell counts how often a LED blinks. From these values the display calculates the electricity consumption of the house in Watts.

Immediately after unpacking the device and reading the user manual the first disadvantage announced itself: the Wattcher can’t cope (well) with solar panels (or any other device which produces electricity). The sensor has no way of detecting the direction of rotation of the disc of the electricity meter. On a digital sensor only blinks its LED, which also gives no indication of consumption/production.

I will therefore loan the Wattcher to several households and ask them about their reactions. I will publish those reactions here.

After more than 10 years of loyal service – it didn’t break down even once – our washing machine went to laundry heaven today. For the past six months it was becoming ever more noisier during the spin dry cycle, a clear indication that the bearings were near the end of their lives. Today it suddenly threw out most of its water, so this marks ‘the end of the road’ for our loyal Indesit.

So now we’re looking for a new one. Of course, it’ll have to be an energy efficient one, I wouldn’t want to buy a washing machine which uses more energy than the old one. After having spent about an hour on the internet it became clear that it’s not easy to compare the energy consumption of washing machines. Most machines have a energy label, but that’s not very useful to me. Apparently at some point in time the A-label was not good enough any more, because you can now buy A+, A++, A+++ and even A++++ washing machines, but what these labels mean in terms of kiloWatt hours and litres of water seems to be a closely guarded secret.

Sometimes I could find a value for the amount of energy and/or water used for a washing cycle, but because I haven’t been able to find  a single case where the type of washing cycle was specified (short/long, temperature) this information is quite useless. My Plugwise measurements show that for a short cycle on 40 degrees C our current washing machine used, on average, 0,65 kWh. (It varies  between 0,34 en 0,72 kWh throughout the seasons, because the tap water temperature varies.) Anyway, I can’t seem to find a user-friendly overview of washing machines where I can sort on the following properties:

• At least as efficient as our current washing machine, preferably more efficient. 0,65kWh for a short 40-degrees washing cycle.
• Good washing quality. It would make no sense to buy an efficient washing machine if some pieces of clothing would have to be washed again.
• Low water consumption. I don’t know the water consumption of our current machine, but obviously, lower is better.
• Price € 300 – 500. Lower is better but I would be willing to pay more for a low energy/water consumption, good quality and service.
• Spin dryer 1400 rpm

To the readers of this website: would some one happen to know of a washing machine which match these specifications?

Oh, and I am not interested in a hot-fill washing machine. We have no solar hot water system and that means a hot-fill washing machine would only raise our natural gas consumption. That would not be so bad if we didn’t have solar panels, but because they generate a yearly surplus it’s financially unattractive to increase that surplus while at the same time increasing our natural gas consumption. I’m specifically looking for a conventional – but efficient – washing machine.

[Update May 31st]

I ordered a Whirlpool Nevada 1600 today. It’s efficient and should do a good job of cleaning the laundry – for a good price. I would like to thank everybody for thinking with me, it was very useful and I learned a lot.

Isolatie, isolatie en nog eens isolatie

Our houses and commercial buildings are leaking like a sieve. Not with water but with heat! Even modern houses which are built to recent building standards need a normal central heating system with a 20-25 kW thermal heating capacity to compensate for the losses through the roof, walls and ceiling. The Dutch building code leaves it to the designer and builder of a house how the heat losses have to minimised to the required level. Often several technical tricks are employed (balanced forced ventilation system with heat recovery, solar hot water heater, etc.) in combination with the minimum amount of insulation to meet the regulations.

A passive house takes a very different approach. Oversimplified the principle behind a passive house is simply ultra thick insulation which makes it possible to keep the house warm during the winter without any heating system, and also cool during the summer without any artificial cooling. To ensure a good air quality in the house all passive houses have a balanced forced ventilation system with heat recovery). Many passive houses in colder climates have a very small heater for when the outside temperature gets too low, but in a well-designed passive house it’s seldom used, in apartment buildings sometimes a heat pump is chosen. To make the houses even more energy efficient usually a solar hot water system is installed for tap water heating, and sometimes solar panels for electricity as well.

On New Energy TV () I stumbled upon a movie () about a renovation project in Rotterdam, where old, draughty, uncomfortable houses were converted into nice, energy-efficient, comfortable passive houses.

Except for the fact I’d rather have a terraced house with a garden instead of an apartment these are pretty much my dream houses. They are energy efficient in a low-tech way, they seem to be located in a densely populated area so most services like shops, shops and public transport are likely close by so inhabitants don’t need a car, or can share a car. Renovation of existing buildings is probably cheaper than constructing entirely new buildings, it can preserve the atmosphere of a neighbourhood and make neighbourhoods much more ‘future-proof’. With old, badly insulated houses sometimes the inhabitants already have to pay more for energy than for rent (usually houses in this situation are rental homes). With the trend of increasing energy prices that is of course in no way sustainable, and converting old houses into passive houses is a very good way of combatting this development.

I hope many more if projects like this will be started.

Distribution of electricity consumption august 2010

Besides for monitoring our solar panels, I have also connected a number of of the Plugwise measuring devices to a number of electricity consumers.

Plugwise () claims on their website that their system should enable large savings on your electricity bill. That won’t fly in our situation because I think we’ve done nearly everything possible to reduce our electricity consumption, but it might very well be true for households that are at the beginning of their energy savings journey.

The plugs allow me to gain insight into the distribution of our electricity consumption. I’ve estimated this distribution () before, but now I can actually (although only partially) measure it. Unfortunately I used a different classification system from the Plugwise plugs, so it’s not completely comparable, but some parts match quite well.

I estimated that our computers used 11% of the total electricity consumption, which turns out to be 9,4% after measuring. When considering the inaccuracies in both the estimate and the Plugwise measuring system that’s not bad at all. The same goes for the refrigerator: I estimated it would use 29% of the total which turns out to be 27,2%. The other categories are defined differently enough to make comparison difficult. I estimated ‘clothing care’ (washing machine and iron) as using up 15%. According to the measurements our washing machine used 10,4%. I estimated we did four to five washes per week which turned out to be quite accurate as we ran the machine 18 times in August 2010. We don’t iron much, so I don’t think the iron (the only other appliance in the ‘clothing care’) used up 5%. I don’t know where the difference comes from but as the actual consumption is less than I thought I’m not going to try to find out.

We have a portable electric heater which – fortunately and unfortunately – came in handy when our roof had leaked badly during the heavy rains in the end of August. I wanted to dry all the woodwork in the loft thoroughly so the heater ran a few hours for two evenings, which used 6,7% of the total. As we have a substantial yearly surplus I don’t worry about that.

Verbruik van de koelkast en CV-ketel in 2010

When looking at the distribution through the year until now two appliances show clear trends: the refrigerator and the central heating system.

In the winter months the central heating system clearly runs for far longer periods to heat our home, and this lowers significantly in the spring.

The refrigerator shows an opposite trend: in the winter the average living room temperature is low (the temperature lowers at night and when we’re not home) and under those circumstances the refrigerator doesn’t have to work as hard to maintain it’s temperature. As the outside temperature rises in the spring the average living room temperature also rises and that increases the refrigerator’s power consumption.

As a bit of a ‘measuring nut’ I love connections like these. A bit of common sense predicts these connections are present but I truly love making them visible in graphs.