In the next few days it will be warm again for a while and then everyone will think back to this summers heat wave. In many houses it then became quite warm and it became even more clear that not enough attention is paid to the cooling of houses in the Netherlands. That is what Jan Engels of Klimaatverbond Nederland, a joint venture between municipalities, provinces and water boards, says.
The last couple of hot summers have raised awareness that something is going on and that we need to take cooling into account. But this has hardly been incorporated into the climate agreement, says Engels.
In contrast to many other countries, houses in the Netherlands often do not have air conditioning. With those a few warm weeks a year, that is unnecessary, was the thought. But that could change as a result of global warming. Policy makers in The Hague, housing corporations, housing design and municipalities need to pay more attention to this, says Engels.
Air conditioning is not the solution
Every municipality must have a plan next year as to how and when districts will be disconnected from natural gas. According to Engels, these plans must also include how municipalities deal with the cooling needs of residents. If everyone gets an air conditioner, there will be problems, which will lead to a huge demand for electricity
During the heat wave in August, electricity consumption already went up by some 30 percent, says energy company Essent. And this despite the fact that only a small proportion of households now have air conditioning.
How is that possible?
There are all kinds of other ways to cool houses, instead of the air conditioning. But which are they? We list them below, with possible advantages and disadvantages
A heating/cooling network is what used to be called district heating, i.e. centrally controlled heating and cooling for an entire district or city. In the winter, your underfloor heating is heated with, for example, residual heat from industry. And in the summer it is cooled by water from a pond or a source deep in the ground.
The water in the underfloor heating pipes should not get colder than about 16 degrees, because otherwise condensation may form around the pipes. In practice you can therefore lower your indoor temperature by a number of degrees.
Such a heat network already exists in many places, but a network that can also be used for cooling only exists in a few places in the Netherlands, such as the new housing estate Houthavens in Amsterdam. It is quite an investment to build. Residents pay energy company Vattenfall a fixed amount per year for the cooling: 205 euros.
Yet there may be a disadvantage, says Jan Engels of Klimaatverbond Nederland: the water you use for cooling heats up further. You dont really want that, because surface water is actually too hot in such hot periods. That can be bad for the oxygen content and aquatic life
According to him, it is better to use separate underground water reservoirs for cooling, so that nature is not bothered by it. This is already happening at MijnWater in Heerlen. Under Heerlen there is a whole system of old underground mining galleries that have been flooded with groundwater. Water at a depth of 250 metres is now used to cool houses in the summer.
Some 500 houses are now connected to it. They do need to be sufficiently insulated to be effective. It is therefore mainly an option for new construction or renovation of houses. Here too, customers pay a fixed amount per year for cooling: 237 euros. Jan Engels of the Climate Alliance thinks Heerlen is a good example of sustainable cooling.
But whether you ever get a connection to a heating/cooling network depends on what plans the municipality has with your neighbourhood.
Air-to-water heat pump
One of the alternatives to the natural gas boiler is the heat pump. You can use it to heat your home, but also to cool it. There are different types of heat pumps. The air-to-water heat pump consists of a unit outside your house that extracts heat from the outside air and thus heats water inside.
That water runs through pipes under your floor (underfloor heating) and heats your house. If you put the heat pump in cooling mode, it works exactly the other way round. The outdoor unit extracts coolness from the air and thus cools the water that runs through your underfloor heating.
Just as with a heat/cooling net, the water must not be too cold, because of possible condensation around the pipes. Because of the limited cooling capacity, the energy consumption is not that bad, says Rimme van der Ree van Klimaatexpert, a company that provides advice on sustainable heating, cooling and ventilation. Its certainly not air conditioning, it has more capacity and can make your house much colder
But the air-water heat pump still consumes a lot of electricity. And the outdoor unit blows out warm air, which is a disadvantage, according to Jan Engels of the Climate Alliance. That contributes to the fact that it gets even warmer outside and youd rather avoid that An air-to-water heat pump quickly costs more than 10,000 euros.
Water/water heat pump
There is another type of heat pump that does not blow hot air outside, the so-called water/water heat pump. It does not extract cooling from the air, but from water from a pipe system or wells that you install under your house or garden.
In terms of energy consumption, this water pump is the most suitable for summer cooling, says Puk van Meegeren of Milieu Centraal. You mainly use electricity to pump water around and that costs very little energy. And the water under your house is heated slightly during cooling, which can be used to heat your house in the winter
You have to have room for such a system under your house and sometimes you also have to obtain a permit for it. Such a water-to-water heat pump is not cheap either; it soon costs more than 20,000 euros. However, you do spend less annually on energy costs than with a central heating boiler.
Keeping heat outside
The best thing of course is that your house stays cool on its own, so you dont need any cooling. New building regulations that come into force next year set out requirements for this. Building permits will then only be issued for houses that meet these requirements. If the occupant behaves sensibly, it wont get extremely hot inside, says Harm Valk of engineering firm Nieman, which advises construction companies.
In such a house, for example, the placement and size of windows must ensure that there is not too much sun in summer. And sun blinds, such as shutters on the outside, can completely block out sunlight. Or special ventilation shutters so that you can get the heat out of your house at night, says Valk. You have to be able to open them without being afraid of burglary, rain or insects
This new standard is nice for new houses, but its no good for existing houses. However, you can apply the same principles in your house, if you have the money and the possibilities to do so. It can be worthwhile to invest in awnings, says Valk. And you have to behave like a Greek grandmother. Open everything to cool air in the evening and close the shutters during the day and lower the blinds