Saving of energy Home renovation pays off

Before planning a renovation, you need to determine the weaknesses of the house. How can you measure the energy efficiency?

byJürg Zulliger 08 Sep 2016

What are typical weaknesses in a building?

The most sensitive parts of a building are the roof, walls or insulation, windows, floors and technical systems. Many buildings are still heated with fossil fuels. As a nonspecialist, you’re often unable to analyze the state of the building shell or the efficiency of your systems. An old oil-fired boiler alone can cause a huge increase in energy consumption if it’s the wrong size and has not been fitted properly.

How can you assess your own home?

One option for analyzing your home is the official cantonal building energy certificate, the GEAK®. This provides reliable information on the current energy efficiency of the building shell and the building as a whole. It also shows the potential for improving the building shell and technical systems. Like the familiar energy labels for household appliances, the GEAK® assigns buildings to energy classes from A to G.

What standard does a new construction have to meet today?

According to the applicable building regulations, a newly constructed building must not exceed an annual consumption equivalent to 4.8 liters of heating oil per square meter. This currently corresponds to energy label B. Over the next few years, the cantons will gradually tighten the building regulations.

What are the differences between one energy class and the next?

There are huge differences. Old houses in need of renovation with energy label F or G often consume four to five times as much heating energy as a new building. The aim should be to renovate these houses so they can get a C label at the very least.

Is it true that many old buildings still do very badly when it comes to energy consumption?

Buildings in energy classes F and G use far too much energy, often the equivalent of 15 to 20 liters of heating oil per square meter. These homes urgently need renovation. We estimate that around 1 to 1.5 million residential buildings fall into this category.

Each year, only one percent of all buildings in Switzerland are fully renovated – far too few. Why aren’t more buildings renovated?

Many people make false assumptions and don’t realize that energy improvements make economic sense. They often forget that there can be a cost to doing nothing. Because a building’s value will fall if it is not well maintained and renovated on a regular basis.

Is it possible to call in an energy consultant as an alternative to the GEAK®?

A consultant is certainly able to make a professional assessment of a house. However, the GEAK® is the only way to categorize a house clearly, while also offering information about possible improvements to the building shell and technical systems. This also makes it the ideal planning instrument. You can request an even more detailed report: the GEAK® Plus. This report includes specific suggestions and up to three alternative ways of renovating the building, depending on the individual situation of the homeowner.

How far can very old houses climb up the energy class ladder?

People generally don’t realize that even when carrying out renovation work, there are specific minimum requirements to be met for individual parts of buildings – windows, for instance. When renovations are made in line with these specifications, even an old house can climb to at least energy class C. If the house is fitted with very good insulation and the technical systems switched to renewable energy sources, it may even be assigned energy label A. If you produce your own electricity via a photovoltaic system on the roof, you can even reach the level of a plus-energy house. Depending on the canton, there are various subsidies to encourage this type of project for each of the higher energy classes.

Comprehensive renovation is quite expensive. Is it possible to do it in stages?

It is important to have a good basic concept. For instance, it’s worth starting with the roof, then renovating the building shell, and dealing with the heating and building systems a year later. It’s a mistake to start with the energy system. If you install new heating without renovating the building shell first, it will often be wrongly designed and far too big.

Specialist information: Ulrich Nyffenegger, CEO of the GEAK® association.