Large-scale public housing programs, such as Minha Casa, Minha Vida (My House, My Life), are an opportunity to invest in sustainable practices that can improve the efficiency of buildings, generating economic, social and environmental benefits. This is the conclusion of the new publication released by WRI Brasil, which evaluates the impacts of 13 measures to increase the efficiency of buildings in public housing programs.
Changes in design, construction or operation of a building can be incorporated to increase energy efficiency or to reduce water consumption. The study, developed in partnership with Mitsidi Projetos, analyzes the potential for reducing greenhouse gas (GHG) emissions and the improved quality of life of the population, as well as the costs and barriers for adoption of these measures.
The measures were simulated individually in each region of the country to identify differences in performance according to climatic and environmental characteristics. These are simple and low-cost actions and technologies that can help reduce the consumption of water and electricity in such developments.
In regards to water consumption, the average reduction can reach 45.5%, regardless of the region of the country, for both single-family houses and multi-family dwellings, such as apartments and condominiums. For electricity, the potential for reduction in consumption is 18.9%, under the same conditions. Considering reductions in consumption, the average monthly savings of expenses per family can be up to US$ 14 in single and multi-family dwellings.
Some of the measures evaluated are low cost or require no additional investment - this is the case with the dual-flow toilet and the materials for facades and roofs, which do not present additional costs. The orientation of bedrooms to maximize sunlight and external wall paint color are zero cost endeavors, and aerators in faucets and LED lamps in buildings, stairs and halls are also low cost. Therefore, with little or no additional investment, it is possible to replace a lower efficiency solution with a better performing option and to gain efficiency that results in savings.
One of the main challenges in adopting such measures in public housing is that some do require additional cost, but the study shows that investment in efficiency measures is not necessarily higher. Additionally, when the costs are indeed fact higher, the time needed for ROI (return on investment) is relatively short.
Efficient buildings contribute to the creation of sustainable cities and the achievement of sustainable development goals. In the case of measures for public housing programs, there is still a significant social impact, as this considers reduced expenses for low-income families. Therefore, the governments and local leaders have a key role to play: to promote projects aligned with this vision and to offer incentives for overcoming institutional, technical and market barriers to the implementation of energy efficient measures in these developments.
The efficiency measures evaluated were divided into three categories: water consumption, electric energy consumption, and architecture. The results below are the result of a simulation of each measure individually - combined with each other, they can generate even greater savings.
Dual-flush toilets: the second greatest potential for reducing water consumption for buildings, with a reduction of 15.6%, for both single-family and multi-family buildings.
Aerator in faucets: with low-cost and easy implementation, this has the potential of offering 6.7% reduction in water consumption.
Rainwater capture: potential to reduce water consumption by 10% in single-family housing and 8.3% in multi-family housing; lower implementation cost for multi-family units because of the division among members.
Individualized meter: in multi-family buildings, it presented a 30% reduction in water consumption.
Orientation of bedrooms: reduction potential 0,4% (applicable only to single-family buildings).
Roofing material: applicable only to single-family dwellings, with potential consumption reduction of 3.6% (in multi-family buildings, the measure would have an impact only on the top-floor units)
External wall materials: the single-family building has four external walls, while the multi-family only two, due to the type of construction. Thus, the results show a variation of 0.10% reduction in electricity expenses in multi-family and 3.6% in the single-family dwellings.
Opening of windows: reduction potential of 0.1% for single-family buildings and 0.7% for multi-family buildings.
Paint color of external walls: reduction in expenses in terms of electric energy consumption in 2.3% in the multi-families and 1.5% in single-family (paint color)
LEDs in living areas: in single-family buildings, the potential for reduction in consumption is 4.5%; in multi-families, the number increases: 6.6%.
Photovoltaic panels: the cost of implementation is high for both types of buildings (US$ 2 per unit), but with a high potential for reduced consumption: more than 92% also for both cases.
Solar heating system: only in multi-family buildings, with potential consumption reduction of 17% (already mandatory for “Minha Casa Minha Vida” single-family buildings since 2011).
LED and motion sensors in common areas such as stairs and halls: applicable only in multi-family buildings, with a potential of reduction of 1.5%.
The sustainability measures offer a variety of benefits, be it in household savings, energy and water savings for municipalities and/or in the reduction of the country's GHG emissions. Understanding who assumes the benefits and costs of implementing measures is critical to properly assess the relevance and feasibility of additional investment for implementation.