Energy prices skyrocket, making efficient energy use a sustainability and economic necessity. But how do you save energy without sacrificing comfort?
Meet Marc Delghust: engineer-architect, an expert in-home energy use, and a lover of bird sounds. At Scone, Marc develops the data and algorithms that run in the background of the app. We don’t know anyone who talks about energy with such passion. Today, Marc discusses six common myths about home energy consumption.
Marc: You often hear that newly built houses are more energy-efficient and offer more comfort than old houses. And it’s true: new homes have a better energy performance, as it is called. You need less energy for the same comfort, and you get better comfort with the same energy use. But there are a few snags here.
First of all: if you have a well-insulated house, you may be tempted to make less effort to save energy. If you heat more rooms, more often, at a higher temperature, you will lose most of your possible savings. Compare it to a bag of light chips, which you eat a lot more because you think it won’t do any harm.
Additionally, new houses are often larger, which does not help with energy consumption either. This is even more so in the case of a house extension, especially if one opts for large open spaces with voids and lots of glass: beautiful from an architectural point of view and indeed enhancing the feeling of space. Still, it does increase heat losses.
And thirdly: if you move from a semi-detached house in the city to a detached house in the countryside, you have many more external walls through which your home loses heat. So, to compensate for that, you have to insulate well. And I’m not even talking about the extra car kilometres you make when you move to a remote area.
So yes, in general, it is true that new buildings are more energy-efficient than old houses, but the choices you make in this respect largely determine how this works out in practice.
Marc: It is good that there are compulsory energy labels (in Flanders, the EPC score). People looking for a house want to know what the energy consumption will be, and it helps people make sustainable choices. But it is essential to say that these labels and scores indicate the average theoretical energy performance. In old houses, they contain many assumptions. After all, we often no longer have all the information about the home.
In addition, residents of old houses often show more economic behaviour - see my point above - but that is not considered. The label or letter code should therefore be seen as a relative indicator. Don’t count too much underlying number in kWh/m². And don’t forget that labels and scores are often about energy consumption per square meter of floor space. You will use more energy in a larger house with the same label.
Marc: Of course, installing a smart thermostat, or mainly smart radiator thermostats, is a good idea, but - perhaps I’m repeating myself - whether it saves money depends primarily on your behaviour. If you only heat rooms when you’re there and turn the thermostat down in the evening, you won’t save extra with intelligent solutions. On the other hand, a smart thermostat makes it easier to maintain your energy-efficient behaviour. A clock thermostat, which you can program to set days and hours, is already very efficient for someone with a fixed rhythm: select the night mode half an hour before you go to bed. For someone with constantly changing shifts, it’s a different matter.
Do you want a new thermostat? Then check with your installer during maintenance if it takes the outside temperature into account (with a sensor outside). This brings the water in your radiators or underfloor heating to a different temperature depending on the outside temperature to run as efficiently and therefore economically as possible during the winter.
Marc: usually, cooking is not where you can save the most on your energy bills. It pays more to look at the heating of your house. In older houses in Belgium and the Netherlands, three-quarters of the consumption is for heating your home. After heating, hot water use is the most important factor in gas consumption. And here, you can also save quite a bit.
Showering uses less water and energy than taking a bath, at least - here we go again - if you don’t spend too long under the shower. Want to save even more energy and water on showering? A water-saving showerhead doesn’t cost much, but it can save you a lot of water and gas, especially compared to a rain shower.
Marc: You indeed have fewer options as a tenant. But there are still a few things you can do: In consultation with your landlord, you might look for cheap and easy interventions, such as a water-saving showerhead or radiator foil if you live in an old house without insulated walls. These are minimal, inexpensive interventions.
Next to that: we often think about the heat produced by a heating appliance, but we forget that we also produce heat. Even if you do nothing, you produce about 100 watts, comparable to a heavy light bulb. As a tenant, you cannot insulate your home, but you can insulate yourself! Always wear a jumper in the house and wool socks. You will notice that you can easily lower your thermostat by a few degrees. And every degree difference will save you 10% in your consumption on average.
Marc: Here’s a tip that can save you some money and doesn’t cost anything: Go on an adventure in your own home and find out where your central heating boiler is located. Usually, it’s in the garage, the cellar, or the attic. Unfortunately, your boiler is often set too high, which is only necessary when freezing outside. So feel free to lower the regime of your boiler to 50 degrees Celsius or even less - just the water for space heating, not the tap water, to avoid the risk of legionella.
Is your room not heating fast enough? Before increasing back the boiler temperature, start by bleeding the radiators (removing any air from the pipes), check the pressure in the system, and free the radiators from anything blocking the warm air (like furniture or curtains). This will make them heat your rooms faster and thus more efficiently.
Only raise the boiler temperature for a harsh winter’s week. Make it easy on yourself and ask your installer to adjust the settings during the annual inspection of your boiler. Or ask them to install an outside sensor so that you don’t have to change anything if it does freeze.
Thanks to Marie Borremans for the intitial draft of this article.