Energy efficiency at home, everything you need to know

The greatest challenge in construction today is energy efficiency. The need to reduce energy consumption in our homes and workplaces is not new; it has been one of the sector's trends for some time, but now more than ever it is essential to invest in it. The European Union has forced Spain to catch up, and starting in 2020, all new buildings will have to be Nearly Zero Energy Buildings.

However, beyond legislation, it is crucial for users and professionals to be aware of the importance of energy efficiency in buildings, as beyond the myth of the expensive investment in adapting to a sustainable consumption model, we can save a lot on electricity or gas bills throughout the useful life of the building. In addition to contributing to an improvement of our planet. Here are some of the benefits of energy efficiency:

1. Retrofitting a home to be energy-efficient can lead to a 40% saving on electricity bills.
2. The livability conditions of buildings are much better under energy efficiency. For example, there are no extremes such as excessively heated rooms in winter or very cold ones in summer.
3. Noise is usually much lower when living or working in a sustainable space. Without the use of air-conditioning systems, noise is reduced, as well as the ability to keep windows closed and much more airtight from the outside.
4. If everyone were to invest in sustainable energy models, cities would undoubtedly be much cleaner. It's not cars or industries that pollute the atmosphere the most; it’s buildings that are the biggest sources of pollution.
5. Unión Fenosa and the Institute for the Diversification and Saving of Energy (IDAE) previously warned in a past study that Spanish homes waste 10% of the energy consumed. This has a yearly cost of 700 million euros, not accounting for all the energy that is used inefficiently.

To achieve energy-efficient homes, we also need to consider several factors. It’s not enough to implement a single proposal; it is essential to understand that the combination of different systems will maximize results.

For example, proper climate control through the use of a mechanical ventilation system is necessary in energy-efficient homes, but to maximize its potential it is also necessary for each room to be sufficiently airtight.

Another very important factor is the energy consumption of appliances, lighting, water heaters, or kitchen stoves. All these systems are easy to change, and it is crucial that, whenever we acquire new appliances or electrical devices, we consider not only their design or price but also their consumption. An energy-saving bulb can cost up to twice as much as the cheapest traditional ones, but its lifespan can be up to three times longer. Just for that reason, the price difference is worth it. Moreover, it will consume only a small fraction of what a traditional bulb requires.

Energy efficiency and building construction

The first thing to consider in order to achieve buildings that meet minimum energy efficiency is their construction. In the midst of the real estate bubble at the beginning of the century, the use of air conditioning and heating equipment became popular.

It was during that time that many houses were built with walls that allowed cold and heat to pass through, poorly insulated windows, and materials that did not guarantee good maintenance of home comfort. Heating and air conditioning systems were installed to provide a sensation of thermal comfort that actually resulted in very high supply bills.

Today, this cannot happen. To bet on energy efficiency, the way our buildings are constructed is paramount. It is essential to maximize the airtightness of all rooms being built.

To improve that airtightness, consider:

• The walls must be built with resistant materials that do not allow heat to escape in winter or heat to penetrate through them in summer.
• Windows and doors must be airtight and very resistant. A large balcony is of no use if the glass allows all the cold to get in during the harshest months of the year.
• In the summer months, it is possible to implement awnings, ventilated roofs or ventilated facades. This will provide a flow of air that will prevent the space from overheating. In winter, its effect also helps.

If a home is built in the most appropriate way, taking all this into account, it is possible that we won’t have to use climate control systems for most of the year.

Energy efficiency and ventilation systems

To minimize the use of climate control systems, mechanical double flow ventilation is not only necessary but also greatly helps improve our health.

Mechanical ventilation systems will be required in Nearly Zero Energy Buildings. However, those that are optimal to guarantee the highest degree of energy efficiency are the double flow ones. In this case, windows must remain closed at all times, and ventilation occurs automatically.

Double flow mechanical ventilation removes stale or poorly conditioned air and introduces air from the outside, previously filtered. This makes the air quality in the home significantly better, allowing the inhalation of high-quality air. For this reason alone, these systems are essential in modern building.

Still, in energy efficiency, they have enormous advantages. The first is that by introducing outside air, double flow ventilation employs a bypass system that heats the air being introduced from the outside in winter through the ducts.

This means that without any expenditure, warm air is already being introduced in winter. There’s no need to use heating. This, coupled with good building airtightness, eliminates our need to turn on costly climate control systems.

In summer, the system is also capable of improving thermal comfort. In this case, the introduced air is cooled. Thanks to this, mechanical ventilation can provide enormous improvements in energy efficiency.

Energy efficiency and lower consumption appliances

The first steps taken in Spain regarding energy efficiency began with light bulbs. Today, it is very difficult to see traditional high-consumption light bulbs, and they are usually used only to replace old installations or traditional lamps that, due to their size, can only use these.

It is also recommended that in our homes we replace all high consumption energy installations with sustainable alternatives. For example, light bulbs are a clear example. However, depending on the situation, ceiling fans can also be installed in situations where we want to reduce electrical consumption and the use of air conditioning.

When choosing appliances, televisions, or any device we use at home, we should look for ones with low consumption. However, what about hot water and home cooktops?

Today, sanitary water can be heated in several ways depending on energy efficiency. At a minimum, it is recommended to use efficient heating boilers. And for home cooktops, they should be electric and low consumption.

Recommendations to improve our energy efficiency

Until a few years ago, energy label requirements were minimal, and many builders only complied with what was mandated by law, without any improvements beyond the minimum. Today, this cannot be the case. Furthermore, it is worth paying a little more for the end user to ensure sustained savings throughout the building's useful life.

In any case, within our homes we can start taking into account many aspects to implement a strategy that, simply, begins to improve the energy efficiency of our homes. We recommend the following:

• Try to find air currents. If you see that air is coming in through a window, a joint, a door, or even a wall, you know you have a leak. The ideal thing would be to seal that joint or improve the airtightness in that area.
• Do you use gas to heat water? Consider switching to storage boilers. They are much more efficient. Electricity can also be a saving option for cooking.
• Protect your windows and doors if they are many years old. With adhesive films, the specialist can cover joints to keep heat in or cold out.
• Of course, the sink is a prime area. The faucets should be single-lever and the sink dual-push.
• Try to take advantage of natural light as much as possible. And at night, use low consumption bulbs.
• In summer, use awnings to block heat and try to ventilate at night when temperatures are lower. Air conditioning should never be set below 24ºC. It won't cool down faster, and it will be a significant unnecessary expense.

If we invest in energy efficiency in homes, the greatest beneficiaries will be the users. But cities and the environment will also see significant improvements.