High-Performance Glass

Project Drawdown defines high-performance glass as any of several mature static glass technologies that can reduce heat flow across the glass including multiple layers, low-emissivity glass, tinted glass, and vacuum glazing. This solution replaces conventional plain glass.

Different high-performance glass technologies have been around for decades and have been proven in commercial and residential buildings to reduce heat loss in colder climates and heat gain in warmer climates. These technologies therefore promise energy savings for thermal systems in buildings and the various technologies have different applications appropriate to their configuration and cost. High-performance glass can greatly reduce the inefficiency of building windows but adoption is limited in some regions. In this report, we examine the potential financial and climate impact of increased adoption of high-performance glass instead of plain glass.

Methodology

Total Addressable Market[1]

The total addressable market (TAM) for high-performance glass was calculated using the Project Drawdown integrated buildings TAM model which collectively calculates the TAMs of building floor area, roof area, space heating and cooling, and all other floor-area driven TAM’s used in the building sector. The estimated TAMs are also subdivided by building type (residential and commercial), and by building climate zone[2]. This model used numerous sources. The total addressable market for architectural glass was determined based on the estimated growth in floor area from this model and the average (residential and commercial) window-to-floor-area ratios from several sources. Data on high-performance glass market share estimates by region were used to estimate the solution’s current adoption[3] in square meters of glass installed (5 billion in residential and 130 million in commercial) and in square meters of floor area “adopted” (33 billion in residential and 1.7 billion in commercial). Since there was already high adoption of high-performance glass in commercial buildings of the Organisation for Economic Cooperation and Development (OECD), this region was excluded from the model for commercial high-performance glass (it was included in dynamic glass).

Adoption Scenarios[4]

Impacts of increased adoption of high-performance glass from 2020 to 2050 were generated based on two growth scenarios. These were assessed in comparison to a Reference Scenario, in which the solution’s market share was fixed at the current levels. The high growth scenarios were based on assumed retrofit rates:

• Scenario 1: For the residential windows, an assumed retrofit rate of 2.3 percent was used for existing building areas, but an increasing percentage (50 to 100 percent) of new construction was assumed to use high performance windows. Similarly for commercial buildings, 2.75 percent of existing buildings were assumed to be retrofitted annually to high performance windows, and 50 to 100 percent of new commercial areas assumed to adopt the solution.
• Scenario 2: For the residential windows, an assumed retrofit rate of 5 percent was used for existing building areas, but an increasing percentage (50–100 percent) of new construction was assumed to use high-performance windows. Similarly for commercial buildings, 5 percent of existing buildings were assumed to be retrofitted annually to high-performance windows, and 50–100 percent of new commercial areas assumed to adopt the solution.

Emissions Model

Heating and cooling energy data for buildings were obtained from several sources. Energy efficiency of heating, and cooling were all found to be between 6 and 9 percent for commercial buildings, but 13 – 17 percent for residential buildings. Electricity and fuel consumption were included, and emissions factors were based on the Intergovernmental Panel on Climate Change (IPCC) data.

Financial Model

First costs of high-performance glass are three to five times those of plain glass and no learning rate was applied since these technologies are generally mature. Operating costs of the glass itself were not included, but cooling and heating costs were included for areas adopted with high-performance glass and with plain glass using global average data.

Integration[5]

The high-performance glass solution was integrated with others in the Buildings Sector by first prioritizing all solutions according to the point of impact on building energy usage. This meant that building envelope solutions like Insulation were first, building systems like BAS were second, and building applications like Heat Pumps were last.[6] The impact on building energy demand was calculated for highest-priority solutions, and energy-related high-performance glass input values were reduced to represent the impact of higher building envelope solutions. The output from the high-performance glass model was used as the input in lower-priority solutions.

Results

Scenario 1 forecasts that 26.6 billion and 7 billion square meters of high-performance glass could be installed by 2050 in residences and commercial buildings respectively. This could avoid 10 gigatons of carbon dioxide-equivalent greenhouse gas emissions and $3.4 trillion in lifetime energy costs. The net cost, however, compared with the Reference Scenario would be $3.2 trillion.[7]

The Scenario 2 (glass area adoption grows to 31.7 billion square meters in residences and 7.5 billion square meters in commercial buildings by 2050) shows 12.6 gigatons of emissions reduced with $3.9 trillion in energy savings over building lifetimes for a cost of $3.4 trillion.

Discussion

It is clear that high-performance glass would have to drop significantly in price to be economically viable in the regions studied. This may be a factor of low energy prices, and helps to explain why after so many years of availability on the market, many areas haven’t adopted high performing glass. Without some interventions that lower the upfront costs to installation, there is limited incentive for building owners to install high performance glass in a world of low energy prices despite the climate benefits. A further split of the energy costs into cooling and heating separately along with a similar split in heating and cooling energy demands in each region might shed more light on the market dynamics and potential for high-performance glass to reduce emissions and building thermal costs. Note also that the use of global averages hides the vast range in building energy used in residential buildings which depend on a number of factors including thermal comfort requirements in individual households.