A High-Performance Car Can Kill You. A High Performance Home Can Save Your Life.

I have the best assignment on the steering committee of the Metro Denver Green Homes Tour — shooting video tours of the homes we choose to feature. Because of Covid, I’m taking that assignment more seriously than ever, because we may not have an in-person tour this year. (The tour is on October 3rd.)

I post these tours (along with the video tours of our listings) on my YouTube channel. Go there to check out some of the more recent tours.

Those videos, however, are limited in what they can convey in 7 to 10 minutes, so I must leave out a lot of what I learn during the lengthy orientation I get from each homeowner prior to shooting the video.

A good example was my tour last Saturday of Jen Grauer and Josh Renkin’s house in Denver. They scraped a house and built from scratch the best example of a “high performance home” I have come across yet — and I’ve seen a lot of high performance homes.

My 7½-minute tour of the house that Jen completed three years ago could not include a lot of what makes it such a good example of sustainability, so I’ll add to it here.

To be “net zero energy,” a solar-powered home like Jen’s has to be super insulated and super efficient in its use of energy. When a home is that tight, indoor air quality has to be addressed to make the home safe. That job is performed by an Energy Recovery Ventilator (ERV).

The ERV’s job is to bring in fresh air from the outside and to expel bad air while maintaining a healthy indoor humidity level. In the typical home, exhaust fans in bathrooms, kitchens and laundry rooms exhaust air to the outside, thereby drawing fresh air into the house only through whatever leaks exist around doors, windows and other penetrations of the home’s “envelope.” An ERV has one dedicated duct to exhaust air and another to bring in fresh, filtered air. This air is circulated through the house via multiple exhaust and fresh air vents around the home. In addition to maintaining indoor air quality, the ERV transfers some of the temperature (and humidity) of the outgoing air to the incoming air when there is a differential between the two.

Let’s say your home is 70 degrees inside, but it’s 100 degrees outside. The temperature of that incoming air can be reduced to, say, 75 degrees by passing it through a heat exchanger where it doesn’t mix with the outgoing air but acquires some of its temperature. Similarly if the outdoor air is below freezing, the ERV might raise that incoming air to, say, 50 degrees. (I could be way off on these numbers. I’m just trying to convey the concept.)

A conditioning ERV (or CERV) monitors the level of carbon dioxide and volatile organic compounds (VOCs) in the outgoing air. You can set a level that is acceptable (say, 900 ppm maximum) and the CERV will increase the flow of air when those levels are exceeded to bring them back to the acceptable range. Whereas an ERV runs 24/7, the CERV only needs to turn on to bring the levels of CO2, VOCs and humidity down to set acceptable levels. A CERV also has an internal heat pump to add heat or cooling. (See my videos of John Avenson’s and Jim Horan’s homes.)

In Jen’s case, in addition to an ERV, she made sure that the home was built with low-VOC products. For example, instead of using high-VOC particle board, her cabinets are made with zero-formaldehyde birch plywood and her island is solid maple and waterproofed with a zero-VOC oil. Her home has no wall-to-wall carpeting, which typically has VOCs in it. (These items are mentioned in the video of Jen’s house.)

Radon is another pollutant which seeps into every home through their concrete foundation walls and slab-on-dirt. To further improve air quality, Jen installed a radon mitigation system.

In summary, a high performance home can not only save you money in the long run (it costs more to build but nearly eliminates monthly utility bills), it can also create a home than extends your life through improved indoor air quality.

John Avenson of Westminster Is a Committed Teacher of Energy Efficiency

The sponsors of the annual Metro Denver Green Homes Tour, held on the first Saturday each October, are preparing to “go virtual” in case an  in-person tour is not allowed.

John Avenson’s house at 9988 Hoyt Place, Westminster

That will be accomplished by creating online video tours of the most notable “green” homes featured over the past 20 years. Since I’m on the steering committee for the tour and have the equipment and experience from creating video tours of homes for sale, I volunteered to create those video tours, starting with John Avenson’s home at 9988 Hoyt Place in Westminster.

By clicking here, you can view the 41-minute video tour, led by John, which I created last Friday. It is highly educational.

John Avenson

Many people, myself included, have created homes which can be considered a “model” of sustainability, solar power, and energy efficiency, but John is surely the only homeowner who has turned his home into a classroom for teaching it. He even posted pictures and diagrams throughout the house with instructional content about this or that feature, as you will see on that video.

He also hosts monthly Passive House meetings in his home theater which are also streamed online. They can be found at www.meetup.com/Passive-House-Meetup-S-W-Region/

John’s house was originally built by the Solar Energy Research Institute (SERI, now the National Renewable Energy Laboratory or NREL) in 1981 using then-state of the art technology, but John has diligently, and at great personal expense, kept retrofitting his home with newer technology, which he is happy to explain to visitors and which he explains on the 41-minute video.

CERV monitor screenshot

For example, because of increased insulation and Alpen quadruple-paned windows, he was able to get rid of SERI’s supplemental natural gas furnace, installing a conditioning energy recovery ventilator (CERV) which is powered electrically. His grid-tied solar PV system provides all his home’s energy needs and has reduced his Xcel Energy bill to under $10 per month — the cost of being connected to the electrical grid.

Some of the technological innovations featured in my video with John were new to me. For example, the Alpen windows across from his kitchen have horizontal micro-etching which redirects the sun’s rays 90° upward to his ceiling instead of straight through the glass, reducing the need for lighting.

John provided his email address in the video, saying that his “learning center” is open 24/7 and that he welcomes all inquiries and visitors.

At Saturday’s ‘Green Homes’ Tour, You’ll Learn What’s Possible for Your Home

The Metro Denver Green Homes Tour is an annual event that happens on the first Saturday in October, which is this coming Saturday. For $10 per person, you get to go on a self-guided tour of 14 Jefferson County homes with a variety of green features.

I consider myself pretty knowledgeable about solar power and sustainability, but every year I learn things I didn’t already know by touring the homes on this tour.

Golden Real Estate is proud to be a platinum sponsor of this event each year. Also, I serve on the steering committee and help in a variety of ways, such as organizing the Electric Vehicle Showcase, which takes place during the post-tour reception, 4 to 6 pm in the CoorsTek parking lot at 10th & Jackson Street in downtown Golden. It coincides with the reception and Green Expo in the American Mountaineering Center (AMC) across the street.

You can register for the tour online at www.MetroDenverGreenHomesTour.org, but you’ll need to pick up your tour book and map, which you can do anytime on Friday at Golden Real Estate’s office, 17695 S. Golden Road, or on Saturday after 9am at the AMC, 710 10th Street.  If you don’t register online, you can do so at the AMC on Saturday morning.

Then you’re on your own, mapping out your own tour based on locations but also on what you read about each house in the tour book.

I couldn’t shoot video tours of every home, but I did choose two that the committee felt represented particularly interesting examples of sustainability. You can see those two videos on the website mentioned above. By watching those two videos you will learn things you didn’t already know, as I did by shooting them.

To quote from page 3 of the tour book, “In our ongoing effort to showcase a wide variety of solutions and lifestyles, you will see solar, of course, and also mini splits, ground source heat pumps and passive solar treatments. You can visit an Arvada sustainable new town home community [Geos] and enjoy many other sustainable lifestyle features such as co-housing, electric vehicles and water wise gardens. You will be viewing the tried-and-true in addition to the latest in innovative technologies, plus learning many steps used to eliminate red tape while going green.”

If you pick up your tour book at Golden Real Estate, let us show you how we transitioned to “net zero energy” using many of the features you’ll see on the tour, including heat pump/mini-split heating & cooling, solar panels, super insulation, and tankless electric water heating. Our monthly energy bill is $10.26 since having our gas meter removed two years ago. If you come in an electric car, you can plug in to our free ChargePoint charging stations — powered by the sun — while we show you around! Click here to read the Jan. 4, 2018, column I wrote describing Golden Real Estate’s transition to Net Zero Energy.

This Saturday’s tour is one of 79 such tours of 894 private homes happening this weekend as part of the National Solar Tour sponsored by the American Solar Energy Society (ASES). And that doesn’t include, for example, last Saturday’s Boulder Green Home Tour, which had 10 homes on it. This is the 25th National Solar Tour, and we have participated for 23 of those years.

Don’t forget the Green Expo during the reception, 4 to 6 pm following the tour. Many companies which implement green solutions will have booths, and there will be an Electric Vehicle Showcase in the parking lot across the street. If you have an EV, bring it for display! If you’re interested in going electric, there will be test drives available. Also, Pedego Golden is bringing electric bicycles which you can test ride.  I have an electric bike, and I love it!

Also at the event will be the CSU Extension 4-H Mobile STEM Lab. The primary focus of the mobile lab is energy production and conservation, energy conversions and mechanical advantage for youth and adults.  Should be interesting!

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