Energy efficiency

Key factors causing heat loss in a building

Energy consumption in a building is affected by various factors, such as the material and condition of the building’s enclosing structures, the usage habits of specific rooms, the geographic location of the building, and its surroundings. The heat required for a detached house with natural ventilation, which is used for the needs of the building during the year, is dissipated in the surrounding environment in the following ways:

• Through windows and doors: 25%
• Through walls: 18%
• Through ventilation: 18%
• Through hot water: 17%
• Through the attic and the roof: 5%
• Through infiltration, heating system losses, floors, basement: 17%

Materials and solutions that limit heating loss

Insulation materials - a distinction is made between natural insulation materials, such as sheep wool or linen, and artificial insulation materials, such as glass and rock wool, and polystyrene. Artificial insulation materials are the most common ones. However, you should remember that making them takes a lot of energy, and their recycling is limited. The advantage of natural materials is that they create a pleasant ambience, reduce health risks and save resources. Depending on the intended use, these materials are available as chunks, mats, plates, sheets of felt, granules or finer-particle materials. Insulation materials made out of renewable raw materials can absorb and emit up to 30 percent of their weight in humidity. Because of this, they can largely ensure that the microclimate in the building is balanced.

Windows - modern windows offer almost as much protection against the cold as massive walls. The thermal conductivity factor, U (W/m2*K), is used as a general indicator of the quality of windows; it shows the amount of heating energy lost through the external walls, windows and the roof. The rule of thumb is the lower this value, the better the insulation. For windows with simple glass glazing, which can still be found in older buildings, the U-value is 5.5 to 5.8 accordingly. On the other hand, currently available airtight windows with double glazing provide thermal insulation from 1.1 to 1.3 W/m2*K. With triple glazing used in energy-efficient buildings, the U-value can be as low as 0.5 W/m2*K.

Ventilation - a system for the controlled supply and removal of air, and in an airtight building its main function is maintaining the necessary circulation of air. If this ventilation system is equipped with a heat recovery system, then most of the heat expelled, and therefore lost, can be reused for heating, improving energy savings. In this way, about 85% of the heat lost through the ventilation system can be reused.

Saving one kWh is easier and cheaper than producing it
Temperature - studies have shown that reducing the temperature of a heated room by 1° can save up to 5% in energy consumption. By observing the optimal temperature conditions in different parts of the building, it is possible to achieve significant energy savings while maintaining the comfort of your stay. Thermostatic radiator valves are the best way to control temperature in any room.

Use automation – programming. You should adapt the heating system to your lifestyle in order to use natural gas energy in an even more efficient and economical way depending on the necessity of its use. When the heating room is not in use, lower the heating room temperature by 2° to 3 °C using the boiler automation. In this way, it is possible to save 7% to 10% on natural gas consumption. It is not recommended to reduce the heating temperature by more than 3 °C within a single 24 h period, because heating the room back to its optimum temperature may take more energy that has been saved from lowering it.

Use of hot water. Energy used to heat water has a major impact on the total energy consumption of the building. The temperature of hot water should be set as low as possible, but no less than 45 °C, to protect your water supply system against any germs that are undesirable and harmful to human health.

Assess your current system, its efficiency, and whether its capacity is sufficient

The maximum output capacity of the heating boiler should be determined based on the amount of heat necessary on the coldest day of the year. In a very well-insulated building, the maximum power for heating should not be less than 15-20 kW, because the building would need power to heat up the water. Compared to modern boilers of the same type, heating boilers older than 15 years are not as economical and eco-friendly.

There are a number of economising factors and technologies that affect the efficiency of natural gas heating boilers:

• Burner power modulation – fuel consumption is most efficient when the burner operates at its maximum output. The heat consumption of a building changes constantly, and the boiler must be capable of adjusting to the continuously changing load, which is done via burner modulation. This means that the boiler can function efficiently at different heating outputs, e.g. at 25%, 50%, 75% or 100% of its maximum capacity. The higher the burner modulation degree, the more efficient the fuel consumption.

• The heating system must undergo maintenance at least once a year, because a few millimetres of soot and a badly configured burner can cause a 5-10% increase in energy consumption. All expansion tanks, pumps, filters, valves of the heating system should undergo regular maintenance, because they are a part of the system as a whole, and any of the components not working properly results in increased energy consumption.

The most complete understanding of energy efficiency solutions available for a production process can be gained through an energy audit.

An energy audit is an assessment of the energy efficiency of independent experts based on estimates of the actual energy consumption of both the building and the industrial or commercial activity in order to determine the potential for energy savings.

The energy audit must encompass 90% of the entire company, and individually determine the sources and consumers of energy:

• the energy consumed to heat the buildings owned or used by the company;
• the energy consumed to produce hot water necessary for non-production personal needs;
• the energy consumed by the lighting system;
• the energy consumed by the ventilation systems;
• the energy used to cool rooms;
• electric, heating and other types of energy (also fuel, if it accounts for more than 10% of the total energy consumption).

The goal of energy efficiency is to reduce CO₂ emissions, which contribute to preserving the environment. During the energy audit, the plant is inspected on site and the data is analysed remotely in order to recommend the best possible solutions for the specific company, such as automation of production units, replacement of equipment with more efficient ones, automation for heating or lighting, change of habits, insulation or other similar solutions. An additional benefit is not only the energy savings, but also the revision of production processes.

As a result of the energy audit, it will be clear to the company how much the costs will be, what energy savings will be achieved and a plan is ready to be implemented with the maximum reduction of energy consumption. The audit plan includes short-term activities with immediate effect and long-term measures that require larger investments.

Certified energy auditors will calculate the time period within which energy efficiency measures will pay off in relation to the investment. It should be understood that small investments pay off already in the first year, but for production companies that need large investments, they will pay off in a couple of years. However, it should be kept in mind that technology is evolving very rapidly and it is not worth investing in activities that only pay off after 10 years or more. Steps must be taken to ensure that the investment pays-off within a reasonable timeframe, as it is difficult to predict how things will develop in the future. The task of energy auditors is to offer a plan that is achievable in the near future (1-2 years) with reasonable costs, because it is not always possible to attract other funding.

It is important to choose a professional energy audit company, because according to the requirements of the Ministry of Economics, the company has to implement the energy efficiency measures included in the audit. Although companies have their own energy specialists, energy audit firms have complicated measuring instruments that can be used to make specific measurements and thus obtain information to work on. As production technologies vary greatly from one sector to another and are most often not available to companies, the competence of auditors is vitally important. The energy audit shall be performed by a team of specialists, each of whom is a specialist in their field. If the audit is performed professionally, it will help the company not only save energy, but also provide opportunities for development, sustainability and improvement of competitiveness.

The timing of the energy audit is very individual for each company. It may take from 1 to 12 months. A lot of time is spent on investment analysis, because you often have to look for technologies outside Latvia. An energy audit should be carried out every 4 years, but the energy efficiency improvement measures implemented and the resulting energy savings should be reported annually.
The cost of an energy audit depends very much on the size of the company and the specifics of the production.
We recommend choosing accredited companies for energy audits.