A green home case study: the first Passive House in Chicagoland – Part I

Chicago-based interior designer Kristin Taghon of Cadmium InteriorsBy Kristin Taghon

Kristin Taghon is co-Owner and Principal Interior Designer at Cadmium Interiors, LLC, a two-person Chicago-based firm specialized in residential and small commercial interior design.

Why should we choose to build and live in a green home?

  • To take it easy on our planet: Green architecture can have a direct effect on our environment by limiting the use of our natural resources and thus reducing our dependency on some of the harmful methods of producing such resources.
  • To reduce our cost of living: A green home can help us lower our long-term cost of living through improved efficiency in terms of energy demands.
  • To take better care of our bodies: Living in a green home can help us eliminate some of the toxins and chemicals that surround us in our everyday lives.

Building a green home: the Passive House in River Forest, IL

Jasmin Marie – my Cadmium Interiors partner – and I had the pleasure to work on a very exciting green home project recently: the first certified Chicagoland area Passive House in River Forest, IL. Tom Bassett-Dilley was the architect and Brandon Weiss of Weiss Building and Development was the General Contractor. As the interior designers, Jasmin and I were tasked with planning the space and specifying healthy and non-toxic furnishings, rugs, window treatments and the paint palette.

The first passive house in the Chicago area

The first passive house built in the Chicago area (picture from Chicago Tribune, Feb. 17, 2013)

The construction of a Passive House reduces the amount of resources needed to live in the house, thereby having a positive effect on the environment and directly reducing the cost of utilities. The amount of energy needed to heat and cool a Passive House is greatly reduced because of the airtight construction and other features that are typical of this green home, such as the use of a rain barrel and solar panels to heat water (called Solar Water). Even natural gas is not used in the house.

In a previous post on this blog, I went over the features of the Passive House Standard:

  1. thickly insulated walls
  2. airtight construction
  3. prevention of moisture migration into the walls
  4. a steady supply of fresh air
  5. optimum sizing of window areas

In what follows, I explain how we applied the first three features to the Passive House in River Forest. I will cover the last two elements in a future post.

Essentials for a green home: insulated walls, airtight construction, and preventing moisture migration into cold regions

An architect and teacher in some of my classes at design school emphasized that “water is the builder’s worst enemy”. Moisture causes mold and mildew and may be a sign of thermal bridging.  Thermal Bridging occurs when two conducting materials come together, causing heat/cold to be transferred through these materials out of the area where you wish to contain that temperature. An example of this is a metal window reveal which lies on the outside of a window pane or the concrete interior wall meeting a concrete exterior wall.

Airtight construction for the green homeEven more importantly, when heat and cold collide, moisture develops much like the condensation that occurs when a cold soda can is taken out of the refrigerator into warm air. The goal is to control the temperature inside by not allowing energy to escape and avoiding moisture and mold by using airtight construction and eliminating thermal bridging.

The construction of this passive house uses ICF (Insulating Concrete Forms) walls that are rigid foam forms that hold concrete in place until it cures and then remains part of the building walls. The foam is a non-conductive material that insulates the concrete from other conducting materials, thus eliminating thermal bridging. The walls of the Passive House in River Forest are 18-19 inches thick and incorporate layers of concrete and non-conducting insulation to eliminate moisture and condensation.  The builder further included a gap between the insulated wall and the siding. This ensures that moisture cannot be trapped under the siding because it gravitates toward the foundation and away from the house via flashing.

Eliminating Pipes and Vents

Condensation dryersThe construction of a Passive House calls for all unnecessary openings, such as pipes and vents to the outside, to be eliminated. The problem is that most ranges and dryers use gas and therefore require an opening in the structure for a gas line and vents to release the hot air.

To eliminate the need for gas in the River Forest green home, we installed two specific types of appliances:

An Induction Range Cooktop as a substitute for the traditional gas range. This range uses a magnetic field to heat the ironclad pan effectively and quickly, resulting in firm control of both the heating and cooling of the pan’s contents. Because the heat stays within the pan rather than dissipating into the air, we’ve eliminated the need to vent the hot air outdoors. This range hood only needs to filter the air of oils from cooking and the smells using charcoal filters. The filtered air then is pulled to the Energy Recovery Ventilator to be exchanged with fresh air coming in.

Condensation Dryers. These are electric dryers that heat the drum around the clothes causing them to sweat out the moisture to be drained through the plumbing. This means a vent is no longer needed to remove the hot, humid air to the outdoors.

Induction range cooktop

We have gone over the first of the main features of Passive House: thick insulation, airtight construction and the reasons for and ways the builder prevented moisture buildup through condensation. In the second part, I write about optimal window placement and how we got fresh air into the airtight construction of the Passive House.

Kristin and co-owner Jasmin Marie, enjoy both the creativity and technical aspects of Interior Design. In Kristin’s words: “I have always loved making, seeing things built, factories, farms… you name it! I love seeing our ideas come to fruition!  Cadmium Interiors always keeps the clients in mind, obsessing about the client’s aesthetics, budget and criteria. We try to find a unique expression of the client, for the client. The end goal is to create a space that is functional, beautiful, and meaningful…like a piece of art. We want you to come home from a hard day and just want to retreat into that beautiful landscape of your home. We strive to provide a space that you want to live in, develop relationships in and become part of the artwork we’ve designed for you.”

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