Expert Advice: Green architecture approaches we should be using in our own homes?
Who are they? Ruth Mandl and Bobby Johnstone of CO-Adaptive Architecture in Brooklyn specialize in environmentally responsible, future-resilient retrofits. The architects converted their own 1889 Bed Stuy brownstone into a Passive House by following a set of building standards for ultra-energy efficiency—their energy bills are literally zero, electric car charging included, and their indoor temperature is steady year round (that’s their kitchen on pages tk to tk). The required gut renovation to achieve these standards is not an option for many, but there are elements to their approach that any homeowner can adopt.
1. Add exterior shading to all your windows and glass doors. “Fabric awnings, hinged shutters, and Venetian blinds or roller shades all make a tremendous difference in blocking solar heat transfer into a space”—which means there’s less need for air conditioning. Ruth and Bobby’s house has motorized exterior metal blinds by Hella that raise, lower, and angle at the press of a button to allow in or keep out the sun and, when fully retracted, are hidden from view. “This small addition significantly reduces your cooling demand.”
2. Make your roof work harder. “If your house has the correct orientation and exposure, solar panels are an effective way to offset your energy consumption. Where solar panels aren’t feasible, green roofs are a sustainable alternative that minimizes stormwater run-off, increases building insulation, and enhances local ecosystems.” (See pages tk and tk or more details.)
3. Upgrade your insulation. “We have a no-foam rule in our office for two main reasons: the high environmental impact of foam production and installation, as well as its negative impacts on indoor air quality.” Spray foam exposes installers and occupants to asthma-causing chemicals and can’t reused or recycled—”which is why it’s important to consider the future use of the materials as much as the current.” Fortunately, there are many alternatives that they like, including: “blown-in cellulose, sheep’s wool insulation, mineral wool insulation (where water resistance is required), cork, and hempcrete.” In their townhouse the architects expanded the depth of their front wall by a foot for extra insulation and used blown-in cellulose alongside mineral wool batts. (For more on insulation, see page tk.)
4. Install high-performance windows. “When upgrading windows, consider triple-paned windows with well-sealed gaskets. This will improve the overall air tightness of your house and reduce the loss of valuable heating and cooling through the windows, and it will also improve sound isolation from exterior noise,” says Ruth. The operation of conventional double-hung windows, she points out, “results in a gap between the panes allowing air to leak through and creating that drafty feeling. We recommend tilt-and-turn windows which create a tight seal around the perimeter and allow for a variety of open positions.”
5. Move toward renewable energy When upgrading existing space heating, hot water heating, cooking or other household systems, consider moving away from oil and gas and switching to electricity from a clean source. “It’s the only way we’ll be able to holistically offset our energy use.”
6. Less and smaller are good rules to live by. “From a sustainability perspective, smaller spaces require less energy to heat and cool.” So do smaller appliances. they note: check out the size of their only fridge on page tk.
Extra Credit: Create a Passive House
When considering a gut renovation or building, the Passive House Standard, Ruth and Bobby point out, increases the construction cost by about 5 to 10 percent, which, over the years pays off in energy savings. “It’s worth noting that many cities are pushing for this to be the baseline of any new building or impactful renovation, and in many countries in Europe, it has already become the norm,” they say. Here are what the architects consider the Passive House key advantage:
- Going net zero—”when combined with solar power, a Passive House uses only as much energy as the building can produce.”
2. Improved air quality: “The air-tight building envelope with an Energy Recovery Ventilator (ERV), two elements in all passive houses, makes for much cleaner indoor air, positively impacting allergies and asthma, especially in relation to our deteriorating urban air quality.”
3. Significant money savings down the line: “There’s little in the way of repair and maintenance, lower or no utility bills, and possible independence from the energy grid.” Get the full details at The Passive House Alliance website, phius.org.
DO YOU RECOMMENDING SEALING A HOUSE THAT’S NOT A PASSIVE HOUSE? I’VE BEEN SEEING ADS FROM COMPANIES THAT OFFER THIS.
HOW ABOUT OTHER UPGRADES, SUCH AS REPLACING THE EXISTING INSULATION WITH SOMETHING BETTER?
CAN YOU GIVE US TIPS ON USING BETTER INSULATION WHETHER SWAPPING OUT FROM OLD OR ADDING AFRESH
FOR HVAC–WHAT DO YOU SUGGEST FOR SOMEONE GREEN-MINDED BUT NOT PASSIVE HOUSE? THIS IS FOR A RESIDENTIAL RETROFIT.
FROM AN ENVIRONMENTAL STANDPOINT, IS SMALLER ALWAYS BETTER IN TERMS OF SIZE OF DWELLINGS/SIZE OF APPLIANCES?
WHEN REPLACING WINDOWS ARE TRIPLE PANED THE WAY TO GO?
NOT SURE THIS TIP WORKS. IT’S ESSENTIALLY TELLING PEOPLE TO BUILD A PASSIVE HOUSE, RIGHT? IS IT POSSIBLE TO ADD TIP ABOUT INSULATION: MAYBE ASK THEM FOR ADVICE ON HOW TO BETTER INSULATE THEIR HOME? AND MAKE THE 4TH TIP ABOUT ERVS, WHICH I’D NEVER HEARD BEFORE!
Use reclaimed and repurposed materials as much as possible. “Things like salvaged wood and recycled-content tile will save on costs, add character to your home, and reduce the consumption of virgin materials.”
Be discriminating when it comes to wood. “When selecting everything from flooring to countertops, to millwork, consider if it is locally sourced to reduce transportation and support local businesses; reclaimed to find new purposes for old materials; and sustainably forested (FSC). Also think about durability, appearance, and size.” Where they live, in the northeast, black locust ticks all the right boxes. They suggest bypassing imported tropical woods altogether.
Find a way to compost your scraps. In their backyard, Ruth and Bobby have a Subpod, a simple, odor-free setup that uses worms and microbes to turn organic waste into fertilizer In the winter, they bring their organic matter to BK Rot, a compost center and bike-powered waste hauling service.