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We found ways to revolutionize buildings and make them more sustainable
Buildings constructed before the 1990’s are responsible for 36% of total building emissions and 13% of the total CO2 emissions in the United States. If we want a carbon neutral future, how might we find ways to retrofit existing homes so they are not contributing to climate change?
At Rocky Mountain Institute I worked on the REALIZE team to address this challenge. We wanted to retrofit homes to create we called “Net Zero Energy” homes. These homes would consume as much energy as they produce. In other words, through implementing energy efficiency measures, envelope retrofits, and solar energy, the homes would generates the total amount of energy required for its heating, hot water and electrical appliances.
We wanted to better understand what it would take to carry out these retrofits in different parts of the country and explore the financials behind it. Here was the process we followed:
01. Gain inspiration from other successful Net Zero Energy retrofit programs
First, we wanted to see what other companies had successfully retrofitted homes to be Net Zero. We came across an amazing company in the Netherlands called Energiesprong that offers Net Zero Energy bundles. An overview of the company can be seen in the video below:
We spoke with the Energiesprong team and learned that their homes are:
Affordable
Attractive
Ensure a 30 year energy performance guarantee
Can be delivered in one week due to 3D printing and standardization
We wanted to create a business model similar to Energiesprong and make deep energy retrofits for the affordable for the residential market in the United States.
02. Understand how we could apply this model to the U.S.
To understand how we could bring this model to the U.S. we have to dive into the technical aspects of building science. We needed to understand what the baseline of a typical home looked like and how we could improve upon that in a sustainable, cost effective way.
We used a program developed by NREL called BEOpt to model the baseline energy use of a typical home. We then looked at each measure of the building, which allowed us to propose different energy efficiency upgrades.
03. Model the economics of Net Zero Energy homes versus other typical retrofits
BEopt also allowed us to see costs of each building measure and compare and contrast different options. We also were able to assess the costs installing residential solar, which would allow the homes to become Net Zero Energy.
From modeling these homes, we found that Net Zero Energy retrofits were actually more cost effective than traditional (non-energy efficient) retrofits. In other words, the retrofit would eventually pay for itself because residents would not be paying for their utility bills!
We additionally created cost abatement curves to show manufacturers where to drive down the cost:
We found manufacturers need to drive down the costs of water heaters and walls.
We found energy efficient lighting and refrigerators provide the most site energy savings and have the greatest IRR.
Learnings
This work has the potential to make a vast impact in the building energy sector because residential energy upgrades are the top unmet demand among U.S. households. There is a deficiency of action among consumers to make homes more energy efficient due to lack of existing financial models and measures showing that deep retrofits are a viable option. By showing people the financial benefits of Net Zero Energy projects and making access to these projects as easy as possible, we can create buildings that fight climate change.
#netzeroenergy #greenbuildings #energiesprong #analogousinspiration #buildings #beopt #nrel #rockymountaininstitute