Most of the energy and effort going into green buildings these days is directed at new construction. This is good, as far as it goes: changing the course of architecture and construction is key to getting the industry to change practices in the long-run.
But we know that in 2020, more than 90% of the housing stock we will be living in will have been built BEFORE 2004. In other words, where we live in 2020 already exists, today.
So the greatest challenge is to figure out how we will “green” existing buildings: retrofit and rehab is the real green challenge.
When Mike Kiefer of GreenDCRealty asked me to take a look at the 100-year old victorian row house on 11th street, I guessed it would be distressed...and it was: rotting window frames, sagging floors and staircase, cracked plaster, a disasterous mix of slapped-up rehab paneling, a basement with a collapsing, sleepered floor.
Still, the wood framing is old growth timber, the brickwork is plumb, the mortar is in fair condition. The location is walkable to downtown, to all major amenities and is 4 blocks from the Mt. Vernon metro stop. This building needs to be taken down to the skeleton, an ideal situation for getting the building done properly for it's next 100 year stint in the national's capital. It is a perfect candidate for a green rehab.
How to wrestle this monster? How do we do it and maintain first sustainability-that is, economic sustainability (profitability)? We can prioritize point-based green certifications, which support marketing efforts and can keep the design and execution on track – say NAHB's Green certification or LEED for Homes. We can approach it with an aggressive energy, maintenance and air quality performance standard – the Passive House pass/fail certification.
But how do we reduce the risk of higher first costs without a predictable premium at sale? And without forcing ourselves into a cookie-cutter outcome or severe compromises that do not support the longevity or actual greening of the building?
Begin with the end in mind: a premium sale price for a superior product. If we deliver 90% reduction in heating and cooling costs, can we sell that? If we can make it net generating (beyond net zero), can we sell that? Can we sell dramatic daylighting? Can we sell near-perfect acoustical performance, near-perfect indoor air quality, and near-perfect evenness in heating and cooling? If we reduce the mechanicals footprint and provide low maintenance and overhead, can we sell that? Can this be achieved at the anticipated premium?
The green potential of any project is not a “go / no go” proposition. The dirty secret of green is that 80% of the “green” materializes from skillful execution and attention to detail during construction. These are basics that all rehabs require, basics that make the difference between junk and quality product. Still, green materials have costs associated with them: insulation is physical, not notional!
We have not gathered enough data to know statistically, but anecdotally we find first costs rise 4-10%, soft costs also rise unless the pre-existing planning and design process already supports the required level of scrutiny and detail. This is for a Passive House with a 90% knockdown on primary energy demand that delivers all of the characteristics detailed above. It will not necessarily deliver the Dwell magazine aesthetic: what makes a house green is largely hidden from view. It will deliver a victorian mansion that is essentially off-grid within walking distance of the nation's capital. A building that is a haven and a hedge against the uncertainties of the future for the next 100 years.