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.

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.

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.

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.

Our Newest Listing Is a Case Study on How to Achieve Net Zero Energy at Home

6187 Terry Way in Arvada’s Sunrise Ridge Subdivision – Just listed at $450,000

By JIM SMITH, Realtor

Regular readers of this column know my commitment to sustainability. Our office is Net Zero Energy, with our 20-kilowatt solar PV system providing all the energy to heat, cool and power our office plus charge our four electric cars, while also providing free charging to the public. My home is also solar powered, satisfying all our electrical needs, although we still have natural gas service.

Readers may also recall me saying that the most affordable way to invest in sustainable features is to buy a home which already has them, since the investment in sustainability pays for itself over time but rarely returns what you paid for it in the resale value of your home.

The home I just listed at 6187 Terry Way in Arvada’s Sunrise Ridge subdivision is a good example of that. The seller, like me, is fanatical about sustainability and has invested over $80,000 in solar power, insulation, daylighting, and other improvements, but the listing price of $450,000, while higher than for a comparable home with a higher monthly energy bill, recovers for the seller only a fraction of her investment.

Meanwhile, whether or not you are interested in purchasing a terrific 2-bed-room patio home, let me use it as an example of the ways you can invest in sustainable features for your own home.

I’ve written in the past about Steve Steven’s 1970s brick ranch which he took beyond Net Zero. I did a narrated video tour of it when it was on the annual tour of solar homes, and it took over 40 minutes to describe all its sustainable features!

This home, however, is a 2002 frame-built tract home that was constructed with above-average but below-optimum energy and insulation features, leaving plenty of room for improvement.  And improve it the seller did!  (You’ll understand why, knowing that she is Steve Stevens’ significant other!)

What follows is a run-down of the improvements which brought this home’s electrical bill down to the cost of its connection to Xcel Energy’s grid. In fact, the home is beyond Net Zero Energy to Net Carbon Positive, meaning that its excess electrical generation more than compensates for the natural gas being used for cooking and heating. On top of that, the seller charges her electric car in the home’s 2-car garage.

Here are the sustainability highlights:

First, of course, a 4.4-kilowatt solar photovoltaic system was installed on the roof. Having done that, the next tasks involved reducing electrical demand so that 4.4kW of solar PV would be sufficient.

Of course, all incandescent, fluorescent and CFL light bulbs were replaced with LED bulbs and fixtures. That alone reduced the electrical load substantially.

Next, five 14- and 22-inch diameter Velux sun tunnels were installed, bringing natural light into all the rooms, nearly eliminating the need for artificial lighting except at night.

Next, all the appliances, including the central A/C unit, were replaced with high efficiency Energy Star-rated models. In the case of the kitchen appliances, they are all stainless steel.

At this point, the electrical efficiency was pretty much maxed out, so attention was given to reducing the natural gas load for heating the home.

Additional cellulose insulation was blown into the attic, bringing it up to an R-100 rating — more than twice what you’ll find in the typical production home. We have a picture of this home after a snow storm, showing the snow melted off the roofs of neighboring homes but not off this home’s roof — clear evidence of good attic insulation.

The rim joist (accessible because the basement is unfinished) was insulated to R-50. This area of the house, I’ve found, is the most neglected area of any house when it comes to insulation. It’s where the joists for the main floor sit on the home’s foundation. Most home builders stuff some fiberglass insulation between the joists, but they don’t enclose that fiberglass in plastic. Cold winter air easily infiltrates through loose fiberglass insulation. It’s the plastic sheeting which stops that air.  And closed-cell foam sprayed between the joists further inhibits air infiltration.

Next, the windows and patio door were replaced with Energy Star-rated Champion products. Improving the windows further was the installation of insulating Hunter Douglas blinds.

Those are the improvements which made the home more energy efficient, bringing it past New Zero Energy. Other improvements worth noting which add value to this home are the large deck with seating on the sunny south side of the house, the beautiful oak Murphy bed with wall storage in the guest bedroom which allows the bedroom to be used as an office, and the 240-Volt wiring in the garage to provide EV charging.

Since this is a “paired home,” the  party wall already had double-wall construction with insulation which reduced the transmission of noise between the units, but my seller added a third wall which consumed 5 inches on the her side of the party wall, into which cellulose insulation was blown, creating an even better sound barrier.

I hope this article has inspired you to improve the energy efficiency of your own home, even if it hasn’t inspired you to call your agent or me at 303-525-1851 to arrange a private showing!

You can view a video tour of this  listing at http://www.ArvadaPatioHome.info narrated by me. It’s just like an actual showing!

NOTE: Showings begin on Monday, March 23rd.

All-Electric Homes Are Practical Now, and Can Help Mitigate Climate Change

The typical American home is powered electrically but heated by natural gas, propane or other fossil fuels. You and I can generate our own electricity with solar panels, but there’s no way for us to generate natural gas or other fossil fuel energy, so the transition to a “net zero energy” lifestyle necessitates turning away from fossil fuels and going all-electric.

Fortunately, technology has advanced — just in the last decade — to the point where going all-electric is totally practical, affordable, and a way you and I can mitigate climate change

At Golden Real Estate, our office was heated with natural gas until November 2017, when we installed a heat pump “mini-split” system and had our natural gas meter removed. With 20 kilowatts of solar photovoltaic panels, we were able to eliminate our natural gas bill but not increase our electric bill. We continue to pay just $11 per month to be connected to the electric grid (which functions as our “battery” thanks to net metering), but we are generating all the electricity needed to power, heat and cool our office building. We even have enough electricity from the solar panels to power our four electric cars without buying any net electricity from Xcel Energy. We hope other businesses will follow our lead.

Making the switch to all-electric at home is still in our future, because — like you, I suspect — we prefer gas cooking, gas grilling, and having a gas fireplace.

If, however, we can get beyond those preferences, it is possible now to heat our home and domestic hot water using heat pump appliances, and to cook our food with electric or induction cooktops and ovens.  Electric grilling is also available, although not as attractive from a taste standpoint to most of us.

All-electric homes was the subject of a talk by architect Peter Ewers at last week’s meeting of the Colorado Renewable Energy Society’s Jeffco chapter.  You can view an archived video of Peter’s talk at www.cres-energy.org/video.

Once we have removed gas service from our homes (and gas cars from our garages), we will have also eliminated the risks of explosion and carbon monoxide poisoning, too.  Wouldn’t that be great?

Golden Real Estate Launches Sustainability Series

As you may already know, Golden Real Estate is a leader in sustainability, as expressed in the value statement printed on all our yard signs: “Promoting and Modeling Environmental Responsibility.” And most of our agents, including myself, are Certified EcoBrokers, having taken extra training in all aspects of sustainability as it applies to real estate.

We’d like to share what we’ve learned with you, so we’re launching a Sustainability Series that will take place on the third Thursday of every month in our office.  We can accommodate 20 or more attendees in our office, but we will move it elsewhere if the demand exceeds our capacity, so please RSVP. You can do so now for all sessions.

Each meeting will focus on a single aspect of sustainability. Here’s the schedule for the first six meetings (subject to change):

Jan. 17th — Home Insulation — Walls, windows, foundations, crawl spaces, attics. (This is a bigger topic than you might think, but it’s also the cheapest and most effective path to reducing energy consumption.)

Feb. 21st — Home Heating Methods — Forced air, heat pumps, radiant floor, solar thermal, and other technologies.

Mar. 21st — Solar Power — Rooftop and ground-mounted photovoltaic, solar gardens, solar panels vs. solar roof tiles, and home battery storage/backup.

Apr. 18th — Electric Vehicles — What’s here now and what’s coming soon in cars, trucks, motorcycles and more.

May 16th — Sustainable Renovation — What are the more sustainable and popular materials and designs?

June 20th — Water Conservation — The latest concepts and products for conserving water use, both indoors and outdoors.

All sessions are 1 hour long and begin at 5 p.m. in our Golden office or nearby if a larger space is needed based on the number of reservations received. The sessions will be led by experts in the field, although you can count on me to add my own comments!

Go ahead and reserve your seat for any or all sustainability sessions now by sending an email to  Jim@GoldenRealEstate.com. We look forward to producing this informative series!

Golden Real Estate’s Sustainable Practices

1)   Our office produces more energy than it consumes. With our 20 kW of solar panels, we heat, cool and power our office and charge our six electric cars. We also provide free EV charging to the general public, yet our Xcel Energy bill is only $11.26/month.  At our request, Xcel removed our natural gas meter.

2)   We accept polystyrene from the public in our “Styrofoam Corral,” keeping over 200 cubic yards of the material out of the landfill every year.

3)   We use only LED light fixtures and have four “sun tunnels” (skylights) for naturally lighting our office.

Click here to read about our transition to “Net Zero” in our Jan. 4, 2018, column, “Promoting & Modeling Environmental Responsibility.”