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Ecohouse Walnut Creek - DIY Solar Workshop

ECOHOUSE WALNUT CREEK, World’s First Two Story Steel and Straw-Bale Residence gets a Solar Array with the help of a DIY Solar Workshop.

The DIY Solar Workshop was the third and final series of workshops held at Ecohouse Walnut Creek. The first series was “Building Walls With Strawbales”, the second was on “Radiant Floor Heating”. The workshop goals are to educate, to train, to promote community, to provide inspiration and to have fun.

The DIY Solar Workshop in Walnut Creek was held on October 27, 2018. It was sponsored by RENVU Solar Distributors (renvu.com) and Sustainable Walnut Creek (www.sustainablewalnutcreek.org) to promote DIY PV Solar. According to Bob, what you see is a lot of advertising by solar companies but there just isn’t a lot of information on obtaining PV using a DIY or a Hybrid DIY/Contractor method.

Bob and Lily knew they wanted solar when they built their home in 2001 but due to budget constraints all they could do was to install the rack footings and electrical conduits to the South facing garage overhang, which was covered using recycled clay roofing tiles salvaged from a local office building damaged in a fire.

They received various installed quotes from solar companies for the garage overhang array ranging from $14,605 to $7,321. After getting these quotes, Bob began calling solar distributors, the companies that sell wholesale solar products to the solar companies who then sell to the homeowners at a markup. This was relatively easy, out of the three wholesale distributors with prices at $4,805, $5,326 and $6,276, Bob went with RENVU at $4,805. RENVU was selected not only on price, but their proximity for Pick Up, their Permit Package Option, Free Solar Kit Guide and their willingness to help sponsor the DIY Solar Workshop. 

Since Bob did not have the electrical expertise for the wiring and hook-up he used a Hybrid model of purchasing the PV modules, racks, micro-inverters and other supplies from a solar distributor and having the array and electrical hook-up installed by contractors.

The solar permit application using RENVU’s optional PermittingPackage ($489) was submitted to Contra Costa County on October 04. The County permit fee was $401. The permit was issued within one week after submitting the necessary structural engineering calculations. 

Bob found out that a worker he used for various handyman jobs was also experienced in installing PV Arrays, which he did for several solar companies in the past. Although Marcus was not licensed he had proven himself to be honest and reliable and with help from two other workers they installed the entire array, the racks, the 7 modules, the micro-inverters, all within a 4 hour period.

The most difficult part of the Hybrid DIY Method was finding an electrician that would do the wiring and hook-up. Bob learned that most electricians do not do solar wiring, but lucked out when he responded to the list of NABCEP Solar Installers at heatspring.com/sean. This is where he found Dr. Sean White, Solar Energy Professor, Consultant, Author, Board Member of Northern California Solar Energy Association and 2014 IREC Trainer of The Year. His new book “PV Systems and the NEC” is free until Sept 12: https://rdcu.be/0GIN. After learning about this interesting installation and DIY Solar Workshop, Dr. White agreed to lead the hands- on workshop segment and provide time for solar questions and answers.

Although it’s a small 2.24kW array consisting of 7 Solaria 320 watt modules, owner Robert Joe proudly said “Small can be beautiful, it’s the final architectural embellishment that we’ve long awaited for, it stands out and makes a statement on what we’re doing in our fight against climate change”. 

According to PG&E the 2.24kW array will offset the electrical cost by 41%. The exterior walls are insulated with 2 foot wide straw bales which has an R-Value around R-50. The house has a livable area of 2,950 sq. ft. with the current monthly electrical cost is $121.00. Now with the array, Bob and Lily Joe’s electrical cost should average around $63.00.


RENVU Solar Distributor
    Modules, rack, Enphase micro-inverters with Enphase IQ Envoy and other miscellaneous supplies $3,654.24 
    Optional Permit Package 489.00
CONTRA COSTA COUNTY Solar Permit 401.00
INSTALLATION of Racks, Modules and Micro-inverters
    Unlicensed Contractors, 4 hrs, crew of three 335.00
ELECTRICAL wiring and hook-up, junction box, the disconnect
    Installing the Enphase IQ Envoy and Labling 500.00
Gross Cost 5,379.24
Less 30% Fed Tax Credit 1,613.77
Net Cost $3,765.47


With a 41% saving on electrical costs amounting to $595.32 per year
The return on investment is 595.32/3,765.47 = 15.8%
The expected payback on $3,765.47/595.32 = 6.3 Years
This DIY Model yielded a 48.5% savings of $3,555.53 over the lowest Solar Company quote of $7,321 

The appreciation value on the house due to the solar installation is objective and difficult to gage, however a conservative estimate of $7,000 in appreciation should not be unreasonable.


With Heart Felt Gratitude to the Ecohouse Walnut Creek DIY Solar Workshop Team: Dr. Sean White, Marsha Cheung Golangco, Ulrich “Uli” Wolf, Chad Buccine, Nick Balamonte, Amoggh Rao, Michael Pollock, Julie “JuJu” Bisch-Pollock and Gregory Check.

Sponsored by RENVU Solar and Sustainable Walnut Creek