1st floor ventilation details

You may have read about the ventilation planning and looked at plans that did show the system. It is always interesting to compare the planning with the actual installation. In this spirit I put a number of imaged together that document the ventilation system.

Ventilation central is the ventilation closet where the Energy Recovery Ventilator (ERV) will be located. This is where all the supply and return ducts come together.

To get an idea of how the ERV would fit and where to terminate the ducts, I built a one-to-one scale model of the ERV. It was very helpful and easy to move around, unlike the real ERV, which weights 70 pounds.

One side of the ERV will connect to the “inside.” The fresh air supply connection is at the bottom with the stale air return at the top.

The other side of the ERV will connect to the “outside”. The fresh air intake connection is on the top with the stale air exhaust at the bottom.

The stale or exhaust air duct runs into and then up the chimney. Right before the duct enters the chimney is the butterfly damper that I had to track down. It should reduce any back-draft problems, as it only allows the air to flow up the duct and out to the roof.

The fresh air supply begins with the wall hood that was so hard to find.

Right on the other side of the wall hood (inside the building) is another butterfly damper, which in turn connects to the fresh air supply duct leading to the ERV location. The duct is already partially covered with spray foam insulation.


Because this duct will convey very cold air during the wintertime, we need to insulated it property. This is not only to reduce heat loss from the building, but first and foremost to prevent condensation on the duct itself. Such condensation can quickly lead to moisture problems and the subsequent risk of mold growth.

Let’s turn our attention to the ducts that lead into and across the 1st floor from the ERV.

Looking toward the back of the building we have the supply line, and next to it the return line.

The supply line feeds fresh air into the master bedroom and the guest bedroom in the back.

The future half bath in the very back of the building has one of the two returns. The line has a branch to the west, leading to the other return in the main bathroom.


While the two returns are toward the back of the building, there are two more supplies, which require another supply branch toward the front.

This branch feeds fresh air into the third bedroom (or office) and the hallway.

All these ducts will have to be hidden behind a drop ceiling. That will require some additional and interesting framing work.

Did you know…

… that the “E” in ERV (Energy Recover Ventilator) actually stands for “Enthalpy” and not “Energy”?

It’s just that most people don’t know (nor did I at the time) what Enthalpy is. To make the product less complicated and intimidating, “Enthalpy” was changed to “Energy.”

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

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