“This must be a most inconvenient sitting room for the evening in summer; the windows are full west.” So spoke Lady Catherine de Bourgh in Jane Austen’s Pride and Prejudice upon entering the house of the main character, Elizabeth Bennet. In the modern age, with electricity and central heating, window orientation is generally not the first thing most of us would notice. But what if we did think about these aspects when designing buildings? Size and placement of windows, along with types of insulation, can greatly influence a building’s ability to stay warm in the winter and cool in the summer. This can, in turn, significantly affect energy costs and carbon emissions.

David Colon, Phius Customer Services Associate for Phius, which certifies sustainable buildings, stated that structures with greater energy efficiency reduce the strain on the electrical grid and that such emissions account for 40% of US carbon emissions. He also noted that these buildings also provide their occupants with constantly filtered air, a quiet atmosphere, even temperature distribution, and reliability in the face of extreme weather events.

Phius focuses on what it calls “passive buildings,” which means that energy efficiency is achieved through the structure’s design, insulation, and window placement rather than through external systems, such as solar panels. In doing so, this reduces energy need right from the start. Haley Harlow, Phius Building Certification Manager, emphasized the importance of “continuous insulation, an airtight envelope, high performance windows, balanced heat and moisture, ventilation, and minimal mechanical systems,” for the purposes of achieving maximum efficiency. Matthew Smith, Public Relations Manager for Efficiency Vermont, which assists people with weatherization, stated that insulation and making buildings more air sealed were “the two most important things.”

Colon stated that the best forms of insulation were those with the largest resistance to heat transfer per thickness. He said the ones most commonly used in Phius structures were foam based insulation, such as high density closed cell spray foam and polylsocyanurate. He also said that most insulation was locally sourced, which reduced carbon emissions and local materials were generally the ones best suited to that area. He gave the example of wood fiber worked well in Maine, but not in Texas, due to termites.

Colon noted that windows were frequently the parts of a building where heat is lost and stated that moderate glazing is often needed and that windows shouldn’t exceed 35% of the window to wall ratio. He also said that windows should be shaded year- round in hot climates, but only in the summer in colder climates. He emphasized the importance of having a well-insulated, compact building with an “appropriate” amount of windows.

While external building materials may seem to be important, both Colon and Harlow stressed insulation and the prevention of heat loss. Harlow said that exterior materials “generally” have little impact on performance. Adobe is frequently cited as one of the better building materials, due to its super insulative qualities. However, Harlow noted that while adobe works well in a dry climate because it absorbs heat during the day and releases it at night, thus keeping indoor spaces cool during the day and warm and night, it would not work as well in other part of the country because it would require transportation and so increase the carbon footprint.

So building with better insulation and more efficient windows is great, but what about that old apartment building with the drafty windows? Can anything be done about that? Colon and Smith both answered in the affirmative, saying that existing buildings can be upgraded for higher efficiency. Colon recommended starting with replacing windows and identifying major sources of air leakage. This, he said, would result in minimizing the loads needed for heating and cooling. Smith said that Efficiency Vermont’s method was to give a “virtual home visit” and identify “what’s working and what isn’t.” Phius refers to it projects as “passive buildings” rather than “houses” and both Colon and Smith stated that their respective organizations work on a variety of structures, including single family, apartment buildings, schools, and hospitals.

However, in addition to the energy savings of these types of projects, making them affordable in the short term is equally important. Smith stated that the average cost as of 2022 was approximately $9,000 dollars for a rebated project. In an effort to address the affordability question, he also said that Efficiency VT offers rebates of 90% or up to $9,500 for low income, 75% or up to $9,500 for moderate income or 75% or $4,000 for higher incomes. Smith also noted that weatherization made buildings more comfortable and used less energy. He cited a study from the Vermont Department of Health, which stated that the economic benefits of weatherization were three times greater than the initial cost. He cited one example where a project cost $2,476 and the savings were $24,757. Colon was unable to comment regarding cost for Phius projects.

What if? It’s a question that could be responsible for a lot of progress. What if we could heat through solar instead of oil? What if we could create buildings of all types that could make better use of natural heat and light? What if that could not only address the housing shortage and also make better housing? For currently standing buildings and for renters, some of these solutions may be more difficult to put into place. However, asking the question keeps the possibilities open.