Portlanders believe in helping the environment, living green, and reducing our impact on the planet. So we asked: which is better for the environment: preserving historic houses, or demolishing them and building new infill houses?
It turns out that there's no contest. Living in a historic house is far, far greener than replacing that house with infill development.
Our historic houses represent many tons of resources, cut from the forests and mined from the earth as much as a century ago. Bulldozing those houses and throwing their remains into landfills is a tremendous waste of resources. To build the new infill building, more tons of trees must be clearcut, metal must be mined, the lumber and metal milled and refined, plastic and paint manufactured and applied, and much of that transported from overseas for assembly. This all consumes huge amounts of energy, generated by burning coal, oil, or other fossil fuels. Resources are consumed and pollution emitted.
The historic house is the environmentally responsible choice. The new building represents a much greater burden on our environment.
"Reuse of buildings with an average level of energy performance consistently offers immediate climate-change impact reductions compared to more energy efficient new construction."
In Portland's climate, it will take 50 years to offset the environmental damage caused by logging, mining, and building that new house.
"For those concerned with climate change and other environmental impacts, reusing an existing building and upgrading it to maximum efficiency is almost always the best option regardless of building type and climate. Most climate scientists agree that action in the immediate timeframe is crucial to stave o the worst impacts of climate change. Reusing existing buildings can offer an important means of avoiding unnecessary carbon outlays and help communities achieve their carbon reduction goals in the near term."
"if the city of Portland were to retrofit and reuse the single-family homes and commercial office buildings that it is otherwise likely to demolish over the next 10 years, the potential impact reduction would total approximately 231,000 metric tons of Co2 – approximately 15% of their county’s total Co2 reduction targets over the next decade."
Demolitions create other environmental damage, beyond wasting natural resources and contributing to climate change. When older houses are bulldozed, lead is released that contaminates the soil on that lot and also surrounding lots up to 400 feet away.
But aren't new infill buildings more energy efficient than older houses? And even though the construction of the new building damages the environment, isn't living in it more comfortable? Not necessarily. Our historic houses can be insulated, efficient heating and cooling systems and even solar systems installed, bringing the efficiency on par with new houses. The cost of upgrading an older home is a tiny fraction of the cost of building a new house.
In historic districts, beautiful older houses can be insulated and made energy efficient, just like in any neighborhood. Oregon offers a 10 year freeze on property taxes to finance renovation of historic houses, and the freeze can be extended for another 10 years for energy efficiency work. Read more here.
If you want to read the full "The Greenest Building" report, here it is.