To make a great building, we need to look at consumption. That means thinking about building envelope from the early stages of building design. Envelope and insulation may not be the sexiest aspects or flashiest systems but they¡¯re the most cost-effective means of reducing consumption for heating and cooling. Envelopes often remain as they were designed for the entire life of the building, while systems can be upgraded. By age 25, building systems often reach end of life but not the building envelope. So that means we better get it right¡ªthe first time.

Let¡¯s talk briefly about five key strategies designers can use to reduce carbon impact¡ªas well as how deep energy retrofits can be instrumental in achieving efficiency.

1.?Envelope

By incorporating passive design strategies (tight envelope, insulation, orientation, controllable natural light) in every building we design, we will deliver significant reduction in consumption (up to 30%) before we¡¯ve begun to mull renewables or advanced energy-efficient systems. Remember that envelope design and assemblies are strongly connected to the building¡¯s embodied carbon, which can represent up to 75% of its carbon footprint over its lifespan. Building orientation (to allow for solar gain and breezes, for example) is a simple decision that we can make early in the design process that will significantly aid in carbon reduction.?

2.?LEDs

Advancements in the quality of LED lighting fixtures and quality of light have made LEDs one of the most cost-effective ways building owners can reduce energy consumption and carbon. LED lighting can save roughly 40% of energy usage. Naturally, LEDs are standard on our new building designs. The return on investment on an LED commercial retrofit is very good. An investment in LEDs will pay for itself, and quickly. And because LED systems are cooler, they may also reduce the cooling load on commercial spaces resulting in further energy savings.

3.?Heat pumps

Air-source heat pumps (ASHP) and ground-source heat pumps (GSHP) pull heat from outside the building to heat it inside. ASHPs use ambient air while GSHPs pull heat from the earth. Heat pumps are a wise choice to replace boilers for clients in less heating-intensive climates or in smaller commercial and residential buildings because they can significantly reduce emissions in areas with less heating demand.?

4.?Cogeneration

Cogeneration, also known as combined heat and power, can support fuel switching in markets with a carbon-intensive grid or when grid connections are not practical. While there are many potential feedstocks for a cogeneration plant, including biomaterial and methane, natural gas is often the source. And natural gas emits far less CO2 than sources like coal.

Cogeneration plants can be 50-70% more efficient than conventional single-source plants. Buildings that use natural gas-powered generators, for instance, can recover heat and save money on energy use while reducing their carbon footprint.

5.?Well-being and comfort

Managing comfort and expectations of building occupants around temperature can go a long way in our efforts toward mitigating energy use. We need to reduce the carbon appetite in our communities by reducing the expectation that schools, offices, restaurants, and shops will be ice cold in summer and cozy and warm in winter.

How cool do we need to make a room? How warm? Finding the right middle ground is the key to reducing wasted energy on overheating or unnecessarily cooling spaces.

Perhaps the greatest challenge to investing in buildings that use less energy and emit less carbon has nothing to do with design or technology. It is all about budget and perception. In many cases, capital or investment budget for a new building is often completely divorced from its operational budget, even though former largely determines the latter. If we can look at initial investment to reduce energy consumption and operational budget over time, features like efficient building envelope and insulation would climb higher on the design priority list.

What are deep energy retrofits?

Retrofitting a building with features such as high-efficiency equipment and a high-performance envelope, which dramatically reduce its energy appetite (and operational carbon needs), is a deep energy retrofit. Today, a sustainability consultant or designer can make a strong business case for a deep energy retrofit¡ªthe investment in energy efficiency will pay for itself in the short-term. While Â鶹´«Ã½ is not an Energy Performance Contract (EPC) provider, we can model building performance and help make the case. We¡¯ve even developed custom parametric tools that model building performance against payback time, helping inform our clients of a plethora of options and investment price points. If the payback can be modeled within 5 to 10 years, the building owner will see a bottom-line benefit to the retrofit.

If it is investing more and expects the return over many decades, it is likely retrofitting for other reasons such as a commitment to being a responsible global citizen, corporate responsibility, and talent recruitment and retention.

Energy performance contracts are one method for contracting for these deep energy retrofits. In this model, you hire a consultant to study your building and demonstrate how an investment would drastically reduce building energy consumption, save money, and pay for itself in an estimated amount of time, say seven years. The contractor offers to do the retrofit and the client pays them back over say ten years. If the model is not achieved, however, that¡¯s reflected in a reduction in payback. That¡¯s the EPC model.