Decarbonizing Homes

How to reduce the emissions, energy demands, and operating costs of existing houses with a reliable assessment and retrofit method.

Course Is Available Now!

  • Team pricing available upon request
  • 3 AIA-approved LU|HSWs

How to Decarbonize Existing Homes

As the demand for more sustainable homes intensifies, architects and builders are increasingly driven by state and federal incentives to reduce the carbon footprint of their homes and to tap into the national push toward electrification. Navigating the complex decision-making process to ensure the best performance of a home that delivers real environmental and economic results can be daunting. It doesn't have to be. In this course, renowned building science expert Marc Rosenbaum offers a clear roadmap for decarbonizing existing homes based on his own specific process and experience. Through this course you will gain a comprehensive understanding of what decarbonization is and how it applies to an existing project. You'll learn how to assess homes accurately, develop an appropriate retrofit plan, and make the most of renewable energy systems to successfully meet a project's performance and comfort goals.

What You'll Learn 

Module One: Understanding Decarbonization

  • What decarbonization means and why we should care
  • Understanding greenhouse gas emissions
  • Importance of working on existing homes
  • General benefits beyond curbing emissions
  • Overview of "The Big Three" concept 
  • Cost expectations
  • Preview of the assessment process

Module Two: Assessment


  • The decarbonization assessment process in detail
  • Balancing focus and investment across "The Big Three"

Module Three: Enclosure Retrofit


  • Weatherization vs. deep-energy retrofits, and deciding how far to take a project
  • Building-science issues to consider
  • Air-leakage reductions and targets
  • Examples of enclosure upgrades that work for both interior and exterior applications

Module Four: Mechanical Upgrades

  • Utilizing heat pumps in retrofit applications
  • Considering existing systems
  • Heat-pump types, uses, and requirements
  • Understanding ventilation options
  • Solving for hot-water demands

Module Five:
Solar and Renewables

  • Establishing guidelines for solar output
  • Understanding area requirements, array options, and design
  • Product selection considerations


Marc Rosenbaum

Marc Rosenbaum, P.E., is a sustainable design consultant known for his integrated systems approach in creating eco-friendly buildings and communities that promote both personal and planetary health. With a focus on collaborative design, he deeply understands the interconnections between people, place, and systems for each unique project. His expertise includes Passive House design, deep-energy retrofits, and net-zero-energy buildings.

As an educator and consultant, Marc frequently speaks on sustainable design at industry conferences and has worked closely with various nonprofit clients including MIT, Yale, Dartmouth College, the Society for the Protection of NH Forests, and the Woods Hole Research Center. He has also worked with commercial clients such as Stonyfield Farm, Tom's of Maine, the Hanover Consumer Co-op, and various cohousing groups and architecture firms on their sustainable project plans.

Marc's work has been recognized with awards from prestigious organizations like NESEA, ASHRAE, and EEBA. Several of his projects have been listed in the AIA Earth Day Top Ten. He is a licensed engineer in New Hampshire, Vermont, Massachusetts, and Maine; a Certified Passive House Consultant; and a LEED Accredited Professional.

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