Energy remodeling: how to improve home efficiency

With the arrival of the new year, we can officially start the countdown for the implementation of the obligation for all new construction to apply the guidelines of the Nearly Zero Energy Building. Starting in 2020, all new construction will have to meet these standards. But what about the old building stock? In the same vein, the rules for energy remodeling aim to address the same issues in the old stock of Spanish housing.

In our country, around 60% of properties were built before the 1980s. And, unfortunately, they have poor insulation and materials that prioritized saving on materials over quality. This translates into a poorer quality of life for their inhabitants, in addition to exorbitant utility bills. All this in a country where one-quarter of the total energy is spent indoors and where the highest energy consumption is that of buildings.

For this reason, efficient remodeling - with an emphasis on improving insulation and ventilation to avoid energy consumption - is not just an option. It is a necessity.

And it is a necessity because European guidelines require a reduction in CO2 emissions by 2020. The ideal level would be a 20% reduction, and for this, old buildings are of vital importance.

If we want to make a home more energy-efficient, the main element to renovate is climate control, as 50% of a home's annual consumption comes from spending on utilities to achieve thermal comfort. Replacing old heating or air conditioning systems and opting for better airtightness and the use of mechanical ventilation can bring improvements for the residents of the home and also for cities, in addition to improving sustainability.

However, implementing an energy remodeling plan may seem complex and costly. The reality is that the cost of the initial investment is recovered over a reasonable period due to the significant savings in energy consumption. How do we proceed?

Developing an energy remodeling plan for homes

The energy remodeling plan for a home will always depend on the type of property in question. There is no standardized solution; it must be personalized, although there are a series of key points that tend to be repeated in all cases, such as the need for mechanical ventilation systems and greater airtightness.

The various variables that must be taken into account in a renovation plan to improve energy efficiency usually include:

• The geographical idiosyncrasy of the location. In Spain, we have a wide variety of climates and the solutions to apply vary according to the terrain. However, it is possible to adapt to it, as in the case of the first passive house that meets the Passivhaus certification in an extreme heat climate
• The type of construction. For example, apartments built before the 1980s tend to have low-quality materials and no consideration was given to any type of thermal insulation. The most complex case is that of attics in apartment blocks, which had no insulation at all in the ceiling, requiring extra efforts in this regard.
• The sun's orientation and the size of the windows. The use of natural light and the impact of sunlight play a significant role in the buildings to be remodeled.
• The size of rooms and of the home. Larger rooms and living areas are much harder to climate control than smaller ones. Houses have additional problems, but it is also easier to adapt to sun orientation cases.

For all these reasons, a well-defined strategy is needed to carry out the energy remodeling. Fortunately, in this type of home renovation, public subsidies can be counted on. We can develop the efficient renovation plan with the following steps:

First action: energy audit of the building

This first step is crucial, as it will tell us the home's energy status and how far it can go. It must calculate the total energy use and the cost involved. To do this, the following analyses can be initiated:

• Annual consumption monitoring.
• Calculation of the building's energy load.
• Thermographic analysis.
• Energy certification of the building.

All this data will provide a calculation that determines how much the building consumes and in what ways. In this case, the study must be conducted by professionals knowledgeable in architecture and energy engineering. Thanks to the data provided, it will be possible to certify where the building fails energy-wise and what plans can be implemented.

Second action: efficient renovations

Perhaps the most important action in the efficient remodeling plan is this second step, which consists of applying solutions to identified problems, especially in climate control. We can identify them in three main areas:

1. Exterior insulation of the building. First of all, it consists of insulating the façade from the weather on the outside. In this case, façade cladding is the first option and the use of insulating windows and even exterior doors is the second. The issue for many homes is that the exterior treatment of the façade depends on the community, although they can opt for more insulating windows. With good insulation, it is possible to reduce energy consumption in climate control by half.
2. Airtightness of the home. While insulation aims to fend off external weather, by making the home more airtight we eliminate unwanted air drafts and also help the home maintain its temperature, with no heat loss in winter. To achieve this, it is essential to identify air leaks, seal spaces and gaps in windows and doors, and fill holes in the walls. With good implementation, airtightness can reduce climate control consumption by between 40% and 50%.
3. Mechanical ventilation. The best way to drastically reduce heat demand is to install double-flow mechanical ventilation systems with a heat recovery unit. Moreover, they are the best solution to ensure health at home, especially after implementing an airtightness process in the home.

The combination of these three factors will make it easier to maintain temperature in winter and summer, and in many cases without the need for climate control systems. Thanks to mechanical ventilation, it is possible to introduce hot or cold air even when the outside environment is the complete opposite.

Third action: efficient installations

After achieving an energy remodeling based on home efficiency, the next step will be to change the home’s installations to ensure low consumption. In this area, there are several proposals that can be made:

• Changing the lighting and using low-consumption bulbs. They save up to 85% of energy compared to traditional bulbs.
• Opting for water heaters and, if possible, reusing rainwater for sanitary use.
• Choosing energy-efficient appliances, thanks to the data provided on the energy label.
• Installing green energy solutions, such as photovoltaic panels. Another good option is to take advantage of the energy produced by aerothermal and geothermal energy.

These actions in the installation of energy efficiency solutions make the energy remodeling even more complete. However, it is essential to note that to achieve significant reductions in utility bills, the measures discussed in the previous sections must first be implemented. Fortunately, there are options in Spain for accessing aid plans for home renovations if conducted from an efficient standpoint.

Grants and subsidies for energy remodeling

From the Ministry of Development, there are numerous aids for improving homes in aspects related to sustainable remodeling, such as the program for promoting the improvement of energy efficiency and sustainability in homes.

These aids for rehabilitation are granted both to owners of single-family homes and to communities of neighbors. After all, it is one of the mechanisms that Spain has to address the necessary reforms in energy remodeling needed from the European Union.

These subsidies make the investment needed to implement necessary reforms less costly. Right now, in Spain, buildings are the ones consuming the most energy, and the expenses generated in homes can be notably reduced. Furthermore, opting for energy remodeling is something that, sooner or later, will be necessary. Right now, with the sharp increases in electricity prices and other energy sources, homes can reach situations of energy poverty even when families living in them are not in precarious situations.