Category Archives: green building

What’s Next in High Performance Building?

After receiving an invitation from an old professor at the University of Colorado to attend a webinar entitled What’s Next in High Performance Building, (link goes to Governor’s Energy Office, webinar will be available online in the weeks to come) well, my interest was piqued. Someone please tell me, what is next?.

And don’t say flying cars, I already fell for that one.

With an undergraduate degree in architecture and twelve years of construction experience, I consider myself more in tune with sustainability and green building than probably most other folks. However, the recent “dip” in the economy has pushed “green” aside in favor of “value” for most of our clients. In fact, its been three years since my design/build business has done a true green build. While my clients’ values may have temporarily shifted, I’m very much interested in maintaining a business that is green at its core, which means keeping current with sustainable trends in architecture.

So it was somewhat disappointing to hear that most of the concepts outlined in the Architectural Trends portion of the webinar are the same concepts that Fred Andreas had been teaching undergrads in his Solar and Sustainable Design course some fifteen years ago, though clearly the technology continues to evolve. High performance glazing, natural day-lighting, passive solar, photovoltaics, ground source heat pumps, greywater systems and eco-machines, to name a few. These have all been in the hopper for quite some time now, and they seem to have only become more complicated and reliant on technology. Somehow we need to find a balance between simple, functional designs and the abundance of technology available to us.

For instance, the most green, energy efficient, cost effective way to cool our house during the summer is really quite simple: we open the windows at night, and then close them through the heat of the day. In this climate, in our old brick house, it works great. Our neighbors run their central air twenty-four seven during the summer, maybe their windows are painted shut or maybe they aren’t around to open and shut them. In this case the problem is that the most efficient way to cool a house relies on human initiative, and we all know how reliable that is. So I think where we are really making interesting progress is with materials and technologies that require little or no human input to respond to changing conditions.

Case and point, in the arena of high performance glazing (otherwise known as really expensive windows or “smart windows” for short) there are now commercially available products such as electrochromatic glazing

and thermochromatic glazing that control solar gains while optimizing natural light. Phase change glazing can physically store energy throughout the day to be released at night. All of these products can act independently of humans, enabling a building to constantly respond to its environment. There are also new technologies being employed to develop predictive intelligence for buildings, using algorithms of human behavior coupled with weather forecasting to predict and respond to future needs, thus maximizing a building’s energy efficiency.

With out a doubt the most interesting part of the webinar was featured speaker Fred Andreas’ talk about the concept of “a living wall.” The National Science Foundation’s Emerging Frontiers Research Initiative recently awarded a grant to a team of C.U. faculty (Fred being one of them) to study living wall materials, which is essentially biomimicry of the human body’s thermal regulation systems. If the Living Wall can provide the 80-95% energy reduction predicted, it will go a long way towards meeting the lofty goal of net zero energy buildings by 2030.

As I understand it, the living wall is like a “thermal diaper”, absorbing and wicking heat either into or away from the contents of a building as needed. An interstitial wall system exchanges heat and light through a capillary matrix of hydrogels and phase change materials. Prototypes are still a couple of years out, so it will be even longer before we know if Living Walls can become a commercially viable part of the sustainability puzzle.

Until then, I’m left to contend with our 1909 single-pane double-hung windows. Which reminds me, I better go close them!


Dreaming of Solar

For as long as I’ve owned a home I have dreamed of installing a solar system that would produce clean, renewable energy for our home (and possibly others). The only problem is the cost. Even with Federal and State tax incentives and rebates from the utility company the cost of a new solar system for our home would come in around $15-20k. That’s a large investment that would require a long period of time to recoup.

So how does one Go Solar without going broke? The answer has emerged before us in the form of partnerships between solar installers and financing companies that offer solar rentals for little or no money down.

This isn’t exactly a new concept. Some five years ago I signed a contract with a company called Citizenre. They were going to install a solar array on my property for free, I would simply pay my electric bill to them and they would sell power back to the grid when we weren’t consuming what the array was producing. While initially we wouldn’t benefit financially from the system, the contract locked our energy rate in for twenty years which promised big savings down the road.

Sounds to good to be true, right? Well at the time it was. I don’t know the full story, but I’ve been led to believe from some in the industry that the local power company would not budge on the rate at which it buys energy from individual producers, basically crushing Citizenre’s business model. Citizenre never reached the critical mass needed and soon thereafter disappeared.

Fortunately, the power company has since come around, realizing that clean renewable energy is good for all of us, even them. That, along with a decrease in incentives from the government to install solar systems has made the rental market that much more attractive. Now, local solar installers like Namaste Solar have partnered with financing companies to provide solar system “rentals”. With very little upfront cost you can have a photovoltaic system installed and maintained for less than your current monthly electric bill. You can lock in your current energy rate for up to twenty years, and yes, it is transferable should you sell your house.

There are limitations of course. We have a nice, big, slightly south facing flat roof over our garage with excellent solar exposure. So for us, it’s easy to get a system that produces enough energy to make it worth it for the financing company. Many older homes have small south facing roof areas, or chimneys or trees obstructing the sun, so they may not be ideal candidates for a rented P.V. system. For anyone that dreams of clean, renewable energy, this is definitely worth investigating in your area.

hey thanks google.

This is a model I’ve been working on in google sketchup.  Fifteen years ago this kind of modeling software cost thousands of dollars.  Today, thanks to google, it’s free.  A perspective like this could take hours to generate on autocad back in the day.  In sketch up, you can fly through your model in real time.  It is truly amazing the resources that are available on the internet today.

Not a very complicated building, in and of itself.  But with the conventional panel siding next to the “rain screen” application, the transitions, flashing and waterproofing techniques, the layers add up.

Need to tweak the spacing of the layers, then probably render  the east elevation to show the finished appearance.

green build

This “green build” was completed two years ago at the height of the market here in Denver.  Back then it seemed anyone could get a loan, and green was the new black.  Reflecting back on the project, it got me thinking.

What exactly made this project a “green build”? Is it still green today?

Good questions.  In this day and age, it seems, the criteria for being green is simply that the word green has been written on it.  The bar for being green has not just been substantially lowered, it’s fallen off the rack and is resting on the ground.  The word “green” has gone mainstream, which in the grand scheme of things is probably good.  But it also means that “green” doesn’t always mean what it means, if you know what I mean

Within the construction world, there are a number of different organizations that have different labels for different levels of green building, sustainable design, energy efficiency, green materials, and so forth and so on.

Some of these organizations amount to not much more than a marketing tool for home builders.  Built Green Colorado, for example, has put their stamp on thousands of homes that stood up to their checklist, which amounts to little more than business as usual in the construction world.  Are these homes more environmentally friendly than tract homes built back in the eighties? Yes, but not by much.  Does the “built green” sign in the front yard help sell the property? Definitely.  Interestingly, what was touted as the oldest and biggest green home building program in the country, Built Green Colorado, is unable to operate through the down economy.  What they were calling an “intermission” on their website, has now lasted two years.

Ok, sure, there’s no surprise there.  Of course some of these green organizations are going to be gimmicky.  Like with any other trend, there are going to be people that jump on the bandwagon and try to capitalize on it, instead of furthering the cause.

At the other end of the spectrum, the U.S. Green Building Council’s LEED Certification program is the global standard for measuring how green a building is.  It was founded back in the mid-nineties by environmentalists whose initial intent was to create a set of guidelines for architects and builders to reduce waste in construction.

While the LEED program has produced tangible results, reducing energy and natural resource consumption, some argue that the forecasted consumption (upon which certifications are based) and the actual consumption of a LEED buildings are totally different numbers.  Of the tens of thousands of projects around the world bearing some level of LEED certification, how many would maintain that status if re-evaluated based on actual performance? Realistically, not many.

The USGBC has attempted to address that concern by requiring building owners to report annual energy consumption data, but it seems largely symbolic as there no process to repeal certification if the building out consumes it’s forecast.  Like the fate of so many that started as a well intentioned grass roots effort, the USGBC seems to have morphed into another bureaucratic organization whose original intent has been whittled away by the developers who see increased value in LEED certified buildings, but want to keep construction costs down.

Getting back to the original question, what makes this house a “green build”? Well, on paper, not much.  It is not LEED certified, it is not “Built Green”, and it is not Energy Star rated.  This was a custom home designed for the owner, not a “spec” home to be sold upon completion.  The additional cost of obtaining certification wasn’t something that could be marketed and recouped on the back end of the project, so why bother? The architect knows it’s green, the owner knows it’s green, and the builder knows it’s green.  Could this be the first structure in modern times to actually be green, without having the word green written all over it? 

While that would be nice, probably not the case. 

Anyways, from the perspective of the builder, here’s what makes this house green:

Urban infill– built on an empty city lot, increases population density in urban core.

Smart design– architect S. Adams designed the space to maximize natural daylighting, using clerestory windows to bring indirect light into the space up high.  Glass block towers illuminate three stories of stairwell while maintaining privacy.  If the sun is up, there is no need to turn a light on in this house.

Modulation and Prefabrication– building dimensions were sized to minimize construction waste (this project produced about 1/6 of the trash usually produced by building a custom home).  Framing components (trusses and roof panels) were fabricated offsite reducing waste and speeding construction.  What would take a week or two on a conventional frame was done in a day and a half.  

Super-insulation–  The 11 1/4″ SIPs roof panels have an R-value of 47.  The 2×6 exterior walls were filled with a water based (no VOC off-gas), spray foam insulation that provided superior thermal and sound insulation.  Gas filled, low-e glass on all the windows and sliders minimize heat loss and reduce energy loads.

Energy efficient systems– on-demand water heaters and high-efficiency furnaces reduce energy consumption, and over time, pay for the additional initial cost.

Blankets– As is evident by the discrepancy between a LEED certified building’s forecast performance and it’s actual performance, a building is only as green as it’s owner.  So turn your thermostat down and throw another blanket on the bed.  Turns out that a “green” blanket is part of what makes this house truly green.