Hey there! I’m Casey Moothart, Carl’s neighbor and now his client. Carl and I share a vision of retrofitting a 100+ year old home to make it as energy efficient as possible. Follow along as Carl and I work to make this 1895 brick home one of greenest homes in Cincinnati.

This renovation will rely on 3 main strategies:

  • Utilize the thermal mass of the brick
  • Create an airtight envelope
  • Insulate exterior to the brick

This post will look specifically at utilizing the thermal mass of the existing home. Built in 1895, this house is solid as a rock. It was built completely out of brick using a triple layer of brick in the wall:

That’s one thick wall!

The three bricks I’m holding are how the brick wall of this home was laid. Like all homes built at this time no insulation was used interior to the brick. Instead the interior brick surface was plastered and that was it. No insulation at all. This picture shows an area in the kitchen where the plaster has been removed to create an exposed brick interior:

Exposed brick interior

In this area of the kitchen there is nothing but brick between the interior and the exterior. To the right (behind the photo of the Renault Alliance GTA) the brick is covered in a layer of plaster, but again there is no insulation.

Living in a completely uninsulated home is clearly inefficient, but it offers a unique opportunity to put all the thermal mass of the brick to use — an opportunity that we are going to take advantage of during this renovation! We are going to apply insulation on the exterior, thereby enabling the brick to be in contact with the interior air and thereby act as a stabilizer of the temperature of the home. Here is a picture of the the northwest corner of the home:

The half white / half gray wall is just begging for exterior insulation

The wall that is white on bottom and gray on top is the north wall of the home. Given the lack of windows on that side can you see how easy it will be to apply insulation over that entire wall? During this renovation we are going to wrap the entire exterior of the home with insulation (polyiso) and then put a new panel exterior over that. Future blogs will document that process.

The point is that once the brick is covered on the exterior with insulation, it will be protected from the up and down temperature swings of the outside. Since there is no insulation on the interior the brick will be in constant contact with the interior air of the home and stabilize at the same temperature as the inside of the home. Because there is so much brick, the brick itself will exert a powerful control over the interior temperature. In the winter when the temp inside the home dips, some of the heat from the brick will move into the interior air to lessen the temperature drop, and vice versa in the summer. The end result is that the interior of the home will tend to want to stay the same temperature and extremes will be dampened. Therefore if there is a really cold winter evening the house will need less heating compared to a home with the same amount of insulation but without all the brick acting as thermal mass. Instead of heating or cooling against the daily ups and downs of the temperature outside you end up heating or cooling against the 2 or 3 day average temperature, which enables a smaller (and more efficient) HVAC system to be used in the home.

Again it is the fact that this home was built with no insulation at all that, ironically, makes it a great candidate for a deep energy retrofit. Stay tuned for more blog posts as the project commences!

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