Discover Arvada’s Geos Community, Where the Homes’ Energy Costs Are Essentially Zero

That’s what it’s like for Jim & Patty Horan, who bought their 3-bedroom, 3-bath, 2,135-sq.-ft. home at 15062 W. 69th Place in Arvada’s Geos Community. They paid $525,000 for it three years ago (July 2017). 

Like all Geos homes, this one has no gas service. With only 6kW of solar panels on the roof, the home is heated by a ground source heat pump. It draws heat from the earth via a 300-foot-deep loop under the home. The heat pump uses very little electricity during the summer to further cool the 55° fluid in that loop, and not much more energy during heating season to heat that fluid to 100 degrees.

On Saturday, June 27th, Jim Horan gave me a tour of his home which I recorded for this fall’s Metro Denver Green Homes Tour. You can view the video at YouTube.com/jimsmith145.

Geos Community’s website describes it as “Colorado’s first geosolar development” and is the only subdivision I know that’s built entirely “net zero energy.” There are developers building solar-powered communities like KB Home’s subdivision on the northeast corner of Hwy 93 and 58th Ave., but they don’t come close to being net zero.

There’s a term for such homes — “greenwashing,” which Wikipedia defines at “a form of marketing spin in which green PR and green marketing are deceptively used to persuade the public that an organization’s products, aims and policies are environmentally friendly.” I’ve always marveled that those KB Homes were built with many of the solar panels installed on north-facing roof surfaces.

Getting back to the Horans’ home, there’s more to going net zero than having solar panels and a ground-source heat pump. Those features must be coupled with energy saving features so that the limited number of solar panels are enough to meet the home’s energy needs — with energy left over to charge an electric car.

Here are some of those features which I covered in my video tour with Jim Horan.

First and foremost is the passive solar orientation of the building with lots of south-facing windows and a south-facing roof for solar panels. Also, there are overhangs above each south-facing window designed to shade it from the sun during the summer while allow full sun in the winter when the sun is lower in the southern sky.

Next, the building’s “envelope” has to be very tight. That starts with foam insulation blown onto the interior surfaces of the roof and exterior walls, replacing the blown-in cellulose and fiberglass batting typical of tract homes built by other developers. The windows are Alpen triple-pane windows which also have foam-insulated fiberglass framing. (Fiberglass is better for window framing than vinyl – not as prone to aging and warping.)

Those elements make a house too air-tight for healthy living, so an energy recovery ventilator is installed which constantly brings in fresh air, using a heat exchanger designed so that the heat (or coolness) of the air being exhausted is used to heat or cool the fresh air being brought into the house. A heat pump within this device, called a CERV, provides further heating or cooling of that fresh air as needed.

In the townhomes at the Geos Community, the CERV works with an air-source heat pump mini-split instead of a ground-source heat  pump to heat and cool the home year-round.

Have you heard the term “indoor air quality” or “sick building syndrome”?  It refers to high levels of CO2 or volatile organic compounds (VOCs) which can build up in a home, especially in a home as air-tight as the Geos homes.

The CERV monitors both CO2 and VOC levels in the house and will bring in additional fresh air when those gases exceed the level set by the homeowner. (The Horans have the level for each gas set at 950 parts per million, or ppm.)

What are VOCs?  If you can smell it, it’s probably a volatile organic compound. Examples include new carpet smell and, worst of all, cat litter smells.

Two appliances in Geos homes also contribute to their low energy load. One is the Bosch condensation clothes dryer, which pulls in cool, dry air from the room. The air is heated and passed through the clothes; but instead of being vented outdoors, the air travels through a stainless steel cooling device or heat exchanger. It does heat the room it is in, so the Horans choose to dry their clothes on an outdoor line during the summer, even though their heat pump could handle the additional cooling load if they didn’t do that. Home Depot sells the Bosch 300 “ventless” dryer for $989.

The other appliance is the heat-pump water heater. It has a heat pump above the tank which transfers the heat from the room into the water. I’ve written about this product before. Home Depot sells a 50-gallon Rheem model for $1,299 which earns a $400 rebate from Xcel Energy and another $300 in federal tax credit if purchased by December 31, 2020. Because this appliance emits cold air, it’s in a pantry which the Horans keep closed in the winter and open in the summer. (I would put it in a wine cellar or in a room with a freezer, which emits hot air — a symbiotic arrangement within one room.)

As you are beginning to gather, building a net zero energy home is best done from scratch, when the additional cost is less than retrofitting a home. (My home is net zero in terms of electricity, but we still burn $30 to $50 of natural gas each month, and it takes twice as many solar panels for my home, which has about the same square footage as the Horans’.)

You may be wondering how much more it cost to build the Horans’ house, which they bought new in July 2017. To answer that, I searched all the comparable homes (2– or 3-story, between 1,500 and 2,500 square feet within 1 mile radius) sold during the summer months of 2017, and I found that the $246 per finished square foot paid by the Horans was actually below the median price ($253 per finished square foot) for the seven comparable sales. And those homes probably pay thousands of dollars per year more for electricity (and gas) than the Horans.

If you want to learn more about Geos community, give me a call at 303-525-1851 or visit the Geos website, www.DiscoverGeos.com.

Cohousing Community Coming to Arvada’s Geos Community

Cohousing communities have been built in Golden and Boulder, and one will be built in the Geos net-zero energy neighborhood on 69th Avenue, west of Indiana Street, incorporating the same net zero energy design elements described in today’s other post about Geos. Ten members are already signed up, including Norbert Klebl, the developer of Geos. When there are 12, design and construction work will begin.

At www.RalstonCreekCohousing.org you can watch some useful videos and learn about their monthly video chats and events. The community will consist of 20 or so units in a U-shaped condo-style building with main-floor common spaces and a courtyard facing Ralston Creek.

If you like the idea of cohousing, check out this one, which has the additional feature of being net zero energy.

Interested in Net Zero Living? Discover Arvada’s Geos Community!

I love showing homes in Arvada’s Geos Community to buyers individually, but there’s a live Zoom presentation sponsored by First Universalist Church of Denver next week which will teach you all you need to know about this great community.

Register for that meeting (Tuesday, May 26, at 7pm) by going to https://bit.ly/FirstU_GEOS.

The homes and townhouses in this community are not only “net zero,” they are “net positive,” creating more energy than the homeowners use, including when they charge an electric car. The homes are so well insulated that they need no furnace, only a CERV, which also monitors and maintains indoor air quality.

Passive House Technology Underlies Going ‘Net Zero Energy’

“Passive House” is a concept born in Germany as “PassivHaus” but growing in popularity here in America. Although its primary focus is on reducing the heating and cooling needs of a home through proper north/south orientation, the placement of windows, and roof overhangs, it also includes design elements that make a home better for its inhabitants. It has many other positive impacts as well, including healthier and quieter spaces, greater durability, and greater comfort for inhabitants.”

Prior to the oil embargo of 1973, home builders did not concern themselves much with making homes energy efficient, but that all changed as we quickly realized how dependent we were on foreign countries for fossil fuels to heat our homes and fuel our cars. Homes built before then were poorly insulated, drafty and less healthy.  (For example, lead-based paint wasn’t banned until 1978.)

The passive house concept took off in America as a result of that wake-up call. The “Lo-Cal” house created in 1976 consumed 60% less energy than the standard house at the time, and the concept continues to mature.

If you participated in any of the “green home” tours that Golden Real Estate co-sponsors each fall, you’ve learned about various passive home strategies in addition to “active” strategies such as solar power, heat pumps, geothermal heating, and energy recovery ventilators.

When “active” systems are introduced to a home with passive house design, they work more easily to create the ultimate goal of a “net zero energy” home — one which generates all the energy needed to heat, cool and power the home and, perhaps, charge the owner’s electric vehicles.  Without passive house design features, you can still achieve net zero energy, but it may require substantially more solar panels to compensate for such factors as inferior orientation, fenestration (windows) and insulation.

You can learn all about passive home technology, including trainings and public events, online at www.phius.org. Also, search “Passive House SW” at www.meetup.org for local events.

An excellent example of new construction which combines passive house design with smart active systems in the Geos Community in Arvada, which you can learn about online at www.DiscoverGeos.com. The homes in Geos are all oriented to maximize solar gain in the winter, but also designed for sun shading in the summer. Some have a geothermal heating, while others have air source heat pumps and conditioning energy recovery ventilators (CERVs). The CERVs installed in the Geos homes not only provide heat when needed but also track the level of CO2 and volatile organic compounds (VOCs) in the air and adjust their function to reduce those levels, thereby improving indoor air quality.

None of the Geos homes uses natural gas, just solar-generated electricity.