EDITOR’S NOTE: This post is part of a series in GBA’s newExpert Exchange program. We will address a quarterly set of topics, the first of which is “Getting to Net Zero.” The series will culminate with a webinar panel discussion among contributing experts.

坐落在科罗拉多州的圣胡安山脉，Creede Americais a small community of modest-sized houses that architect/developer Avery Augur describes as “houses for mere mortals,” ranging in size between 850 and 3000 sq. ft. Construction that emphasizes sustainability and livability while keeping to a tight budget is foundational to Creede America, a vibrant neighborhood inspired by thetenets of New Urbanism—walkable, dense, and connected—in this decidedly non-urban landscape.

Due to the lengthy and extreme cold season, the biggest energy demand for buildings in this climate is heating; and designing heating systems to be as efficient as possible is a priority. At last count there were 22 houses in the Creede community. While all can be considered eco-friendly, so far just one is net-zero.

“My client didn’t want to do a system that burned gas,” explains Augur as to why propane wasn’t an option. “His priorities were green technologies and net-zero [energy use].”

“A propane system is considerably cheaper and a custom-designed air-source heat pump and solar array can add as much as $50,000 to construction cost,” continues Augur. “The value of no utility billseveris getting the attention of banks and appraisers, who are beginning to factor the tradeoff between no utility bills and home values into the calculations of what buyers can afford.”

Augur has installed geo-thermal systems in several of his houses and touts their high level of energy efficiency. But the prohibitive expense of installing geothermal wells required by a water-source system, the historical go-to for heat-pump systems, dissuaded his client. In the end, they opted for an air-source heat pump manufactured by Space Pak, one of a new generation of such systems that has hit the market recently. The beauty of newer heat pumps, notes Augur, is that they “are capable of operating in considerably colder climates than earlier technologies.”

Augur与他的长期机械和结构工程合作伙伴的资源工程集团的团队紧密合作，后者使用来自多种来源的温度和太阳数据为家用的热泵指定了热泵。基于该地区的历史气候数据，工程师对房屋进行了负载计算，并相应地调整了系统的尺寸并随附太阳阵列。由于阵列是一个网格绑定的系统，因此团队还必须了解当地电力提供商的政策，这些政策关于所有者被认为是生成的电力并将其放回电网的电源的利率。

To improve performance further, the system pushes glycol through-tubing in the concrete slab floor of theshallow, frost-protected foundation, which is also the finished floor. This allows the floor to act as a powerful heat sink to retain warmth inside the house while using considerably less energy than a propane system. Augur concedes that the混凝土的生产是“一个相当大的能源密集型过程”。但是，一旦现场，他就反驳说：“不再有任何排放。”在冬季，辐射地板加热使房屋保持温暖，并消除了强迫空气的需求，从而消除了压缩机和风扇的声音。

Regarding the house’s other sustainable-construction features, using locally sourced beetle-killed spruce siding minimized the emissions associated with long-distance material transportation. “The wood is not kiln-dried, so you have to spend a little more time for it to air dry and get to the moisture level you want,” explains Augur, but that’s offset by the wood’s reasonable price and low maintenance over the long term. “We’ll stain it, but in this weather, it will split and crack. If you’re not keen for that character, it’s the wrong material for you.” The look befits Augur’s intention to pay homage to the town of Creede’s mining history through architectural nods to the regional vernacular. Inside, ceilings are tongue-and-groove pine and trims and finishes are minimal. Low-VOC paint was used on all the walls. “We’re a design-build firm and most of our projects have budgets that don’t include an interior decorator,” says Augur.

像所有Creede America Houses Augur建造一样，这是紧密隔热的Demilec开放式喷雾泡沫在墙壁和天花板上的闭孔。“信封非常常规，但是我们使用了带有吹风剂的喷雾泡沫，在安装过程中，在温室气体排放方面，它对环保的剂量更加环保。”像所有奥古尔（Augur）的房屋一样，当门和窗户关闭时，没有付出巨大的能源罚款，与重新加热外部温度相关的空气时，该房屋具有空气交换热恢复呼吸机（HRV），以将新鲜空气引入房屋中。没有这样的系统，室内空气质量会降低甚至不健康。奥古尔说：“在这种气候下，我不会建立一个。”

空气交换系统具有另一个及时的特征，因为在短冷却季节时，人们对新鲜空气和通风的普遍关注。尽管高空阳光下的夏天炎热，但即使在最温暖的夏季，夜间和早晨的新鲜空气也可以使房屋保持舒适。

在冬季，辐射地板加热使房屋保持温暖，并消除了强迫空气的需求，从而消除了压缩机和风扇的声音。

The entire house is electric—there is no gas, propane, or oil-fired equipment in the house. Electrically, in its first year the solar array produced 17,000 kwh while the house consumed only 10,300 kwh.

“房子包括许多事情我们做的l our projects, such as a tightly insulated building envelope with a heat recovery ventilator to ensure good indoor air quality, and locally sourced beetle-kill spruce siding,” explains Augur. “It just takes it a step further in terms of net zero by getting rid of natural gas and adding the air-source heat pump and solar system.”

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Janice Rohlf is a contributing editor atFine Homebuildingmagazine. Photos by Charles Davis Smith, FAIA.