House Feature

A Financial Approach to a Net Zero and Hurricane Proof Retrofit

By Camille LeFevre, Home Feature Editor

Last Updated: Mar 10, 2025

After a career that has included designing solar-energy systems and energy-efficient lighting systems; starting his own company, ShineRetrofits, which he built up and sold; and working in eCommerce, real estate investing, and finance, entrepreneur Erin Shine had an idea:

How Much Does it Cost to Live in a Net Zero Home?
A Remarkable Retrofit
Advice to Homeowners

Let's prove you can sustainably and attainably build houses that are actually affordable for first-time homebuyers.

His first project, a retrofit and remodel of a 1984 wood-frame home in the Cape Coral area of Florida, proves just that. After pouring through MLS listing in cities throughout the US, he says that community was his best option. He grew up in the area, still has family there, and knows the real estate market. Also, the house had a perfect roof for a solar array.

"It was an experiment to see if it would work," he says. "I'm in my mid-30s. Half of my successful professional friends still can't buy a house." In Cape Coral, Shine purchased the 1,835-square-foot, three-bedroom, three-bath house for $199,900. His project costs were $84,357.14. The total amount spent, then, was $284,257.14. For reference, the median home price for this area is $318,301.

Shine's solar-powered, all-electric, net-zero, and hurricane-resistant home is now his primary residence. He also started a new company, Attainable Home, to showcase the home and grow the home retrofit business to be more sustainable.

For Shine, the process of retrofitting a home to be more sustainable was all about numbers. Using a spreadsheet, he analyzed the upfront and payback costs of every upgrade. Why? "Real estate is the number-one wealth-building vehicle," he says. "Attainable Home is about how we can remodel homes realistically and affordably."

How Much Does it Cost to Live in a Net Zero Home?

The home's 9.38kw solar-powered system has 24 panels and micro-inverters. The panels are also "the highest-rated ones I could find for hurricane resistance." The array powers not only the home but also Shine's Tesla. Shine calculates that he's saving $1,800 a year in electricity costs, and $592 a year in gas, for a total yearly electric and gas savings of $2,392.

The mortgage payment, after a 20% downpayment and an interest rate of 2.99%, is $926.34 per month.
His property tax payment per month is $95.98.
Homeowner's insurance per month is $147.17.
The water bill is $85 per month.
The monthly utility solar net-metering hookup fee ("even if you're net-zero") is $21.69.
The home has also budgeted $1,000 per year for maintenance ($83 per month).

So, the total monthly cost to own the house, then, he says, is $1,359.18.

Having the option of using the property for rental income, if necessary, is also vital to Shine. "I wanted to be sure I could rent it out for 10-15% above all ownership costs, including long-term maintenance," he says. "A similar home in this area rents for $1,750+ per month unfurnished and more than $1,900+ per month furnished."

Shine's home, as well as any other primary residence, "will most likely remain your own home," he says. "But unexpected things happen in life." Relocation due to a new job, career, or family commitment could result in a move. "You want to be able to rent it out your home while covering all of the costs to own it," he says. "This approach allows you to ride out any temporary setbacks or market cycles. It also allows you to benefit from long-term homeownership and wealth-building."

A Remarkable Retrofit

Finding a home with a large south-facing roof, with shingles installed six months prior, was a definite plus, Shine says. "The roof was a primary reason for buying the home," he says. "It also faces 180 degrees south; a near-perfect angle for optimal solar-energy production." The roof also had hurricane ties in the trusses, "which gives you a huge insurance discount," Shine says.

He didn't add more insulation to walls, ceiling, and floors "because the payback wasn't there," he says. Shine did, however, increase air-tightness by 44% by replacing existing windows and doors with ENERGY STAR hurricane-impact, double-pane windows and doors.

He caulked around the baseboards and flooring with clear silicone. He put foam-insulated cutouts behind the electrical outlets. He had the ducts caulked inside. He also dry-walled over gaps, including over a soffit open to the attic.

"The blower-door test went from 6.8 to 3.7," he says. Shine kept the existing ENERGY STAR appliances. The retrofit included "combining energy efficiency, hurricane-proofing, and solar energy," he says, with help from energy modeling and consultants from a local energy-efficiency company. The project also has new paint inside and out, new flooring, plumbing, electrical, and a new kitchen. Shine also redid the backyard to include sitting areas, a shower, and other amenities.

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Advice to Homeowners

"I'm not an expert in building science," Shine says, adding, with a laugh, "I know enough to be dangerous."

"My passion is for macro-economics, monetary systems, and real estate investing," he continues. "I come from the commercial world, in which nothing happens unless it makes monetary sense." This home "proves you don't need to use natural gas. You can retrofit an existing house into a comfortable, all-electric, net-zero home with all of the conveniences. As an investment, retrofitting a home in this way beats out bonds and the stock market. By making sure the retrofit makes financial sense, you're enjoying energy savings, as well."

The main focus of Attainable Home, he says, "is the financial side of the industry and sustainability. Start with the lowest hanging fruit when you're doing efficiency or renewable projects and trying to make the financing work. Chip away at all the items with the lowest payback on your money and highest return on investment first. This approach will, in turn, bring down the overall costs for the complete project."

Shine's project "is now a full net-zero asset and home. The home, and my lifestyle, produce zero-emissions net-net (after a short period to recoup the building costs and emissions)." Shine has also established that his primary residence could also be used as a rental if needed. "Beyond that, this house checks all the boxes of using real estate for long-term wealth building and asset ownership."