Rise | We've Done the Research
Passive House Retrofits: The EnerPHit Program
One of the most common sayings in the green and sustainable housing industry is: "the greenest house is the one that is already standing." That idea was first expressed by Carl Elefante, a past president of the American Institute of Architects. Elefante based his reasoning on careful analysis of the embodied energy tied up in the construction materials that go into building a new home. Sustainable construction standards and technologies have certainly improved in recent years to the point that new homes can be much more energy-efficient than older homes. But, the total energy needed to source the building materials, manufacture, transport to the building site, and use them to build a new home has a considerably higher carbon footprint than the expected operational energy savings.
When deciding between tearing down and renovating, the numbers show that renovating older homes is undoubtedly more sustainable.
Table of Contents
Historical Sustainable Renovation Challenges
In the past, the scope of green renovation projects was somewhat limited. To be sure, you could always purchase a weatherizing kit to stop the drafts from around your windows and doors. But, the building envelope of many older homes was often seen as too compromised to make meaningful gains in terms of energy efficiency. In terms of thermal bridging, some older homes have frames that don't allow for maximum airtightness. If foundation issues are present, thermal bridging at the wall-to-floor junction can also be challenging. If your older home has very small rooms, thickening the walls to increase the insulation might not be feasible. New builds were seen as necessary if you were to achieve high thermal comfort levels with a radically reduced energy consumption.
What is the EnerPHit Passive House Retrofit?
The Passive House Institute (PSI) of Germany recognizes that many older buildings cannot achieve the passive house standard's rigorous demands for new homes. Luckily, the PHI's EnerPHit renovation certification allows renovations of older homes to the exacting passive house standards. The EnerPHit renovation plan, when implemented in its totality, can enable even the oldest and draftiest of homes to achieve energy efficiency and reduce energy demand. Certified homes generally reach reductions between 75 and 90%, and some have even achieved up to 93 percent.
Newly built zero carbon homes might be able to outcompete even the best passive house retrofit. However, the ability to resurrect an older home while simultaneously reducing heating demands by over 90 percent is a resounding achievement.
Of course, the particular retrofit strategy will differ according to the specifics of each home. According to PSI, for a house to receive the EnerPHit certificate, it must include some of the following sustainable building criteria:
- reduction of thermal bridges
- improved thermal insulation
- considerably improved airtightness
- use of high quality, energy-efficient windows
- efficient heat generation
- ventilation with highly efficient heat recovery
- use of renewable energy sources
Costs and Benefits of Passive House Renovations
Living in an old, drafty home that's cold in the morning and costs a fortune at the end of the month when the energy bill comes can undoubtedly be frustrating. The most apparent advantage of renovating an older home towards the rigorous passive house standard is that you will immediately notice your home's increased livability. Passive house renovations will lead to more comfortable indoor air temperatures. You'll also have better air circulation and improved indoor air quality by installing a heat recovery ventilator. These are just two of the immediate benefits that an EnerPHit retrofit will deliver.
Clearly, the substantially reduced energy demand will also show up on your monthly utility bills. You will save money due to the increased thermal performance and energy efficiency of your home. For carbon-conscious homeowners, the considerable reduction of your home's greenhouse gas emissions is also a meaningful benefit to be taken into consideration.
Building Materials
Shop high-performance building materials that are vetted for benefits to your health, your pocketbook, and the planet.
Quickscrews Pan Head Pocket Hole Screws
Quickscrews Square Flat Head Wood and Particle Board Screws
AFM Safecoat 3 in 1 Adhesive
Autoslide Motion Activated Pet Door System
Tobias Roberts
Tobias runs an agroecology farm and a natural building collective in the mountains of El Salvador. He specializes in earthen construction methods and uses permaculture design methods to integrate structures into the sustainability of the landscape.
