The first thought you’ll have when entering Nicholas Koch’s Austin home is how remarkably peaceful and comfortable it feels – a quietude reminiscent of a yoga class just before it begins.
In Koch’s home, there is no direct light. You’ll never see a light bulb in the ceiling, but instead may notice that all light is either reflected off walls or diffused through windows as natural sunlight.
The home, built in 2010 by Koch, was the first passive home in Texas to be certified by the Passive House Institute, requiring it to meet a specific set of energy standards.
Passive homes are “net zero,” meaning they don’t utilize any on-grid electricity. And in a country where the average household spends at least $2,000 a year on energy costs – over half of which goes to heating and cooling, according to the EPA’s most recent “Buildings and their Impact on the Environment” report – they represent an alternative building format for the future.
The average household spends at least $2,000 a year on energy costs – half of which goes to heating and cooling.
With energy costs rising, it’s no surprise that the concept of passive homes is catching on, especially here in Austin where summers are sweltering.
Some passive homes use alternative sources of energy, such as solar or geothermal, but the key way these homes save money is with highly efficient insulation and a well-sealed thermal envelope.
Koch’s home uses 12-inch thick walls – wood he repurposed from the home’s old roof – with a layer of super insulation and a sealing barrier that surrounds the exterior of the walls to make his home airtight.
This airtightness and a balanced ventilation system offers high air quality and efficient air exchange, both of which are vital to maximizing energy efficiency, regulating moisture and removing pollutants from the indoor air. For the large number of allergy sufferers in Austin, these building techniques can make a sizable difference in health and comfort.
His design also uses a heat pump water heater, which concentrates warm air to heat the water in his home while exhausting cold air to keep things cool. The system is also able to act as a dehumidifier for his home. Financially speaking, the goal of passive home building is to spend more on the home’s windows and insulation and less on an air conditioning system. This is the concept Koch’s company, Equitable Green Group, adheres to in its designs for homes in Texas.
While a typical homebuilder would spend $15,000 on an HVAC system and $5,000 on windows, insulation and the home’s envelope, passive homes allocate roughly $15,000 on windows, insulation and sealing the home’s envelope while using a smaller, more efficient HVAC system that typically costs about $5,000. “Everybody should be building passive homes here in Texas because they don’t cost more,” says Koch.
According to the Passive House Institute, though, achieving passive house standards can require an additional up-front investment of 10 percent of the home’s construction budget.
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