Build Your Own Solar Greenhouse

By Charles Winslow
Published: March 21, 2018 | Last updated: February 24, 2019 05:17:47
Key Takeaways

If you want year-round gardening opportunities and a pleasant living space to enjoy in all four seasons while keeping your energy bills low, consider building a solar-heated greenhouse that is attached to your home.

Source: Derrick Neill/

Greenhouse. Solarium. Hothouse. Conservatory. Whatever your term, we're talking about that cozy spot for your cherished plants. Greenhouses are an element of home design that garden enthusiasts, and especially indoor and hydroponic aficionados, not only appreciate, but relish. A spacious, climate-controlled greenhouse is a dream indeed.


As you undoubtedly know, there are inexpensive greenhouse kits that you can set up in your backyard for as little as a few hundred dollars. But, for something more substantial, something larger, permanent, convenient and useful year-round, why not think about building a solid structure attached to your home?

Since my wife and I build, live in and market energy-efficient homes, and develop new lighting and hydroponic technologies as our careers, our greenhouses have progressed in space and efficiency with each house. As hydro enthusiasts and developers for many years now, we have always needed that spare room for growing and lab testing.


Our latest and most advanced, which we describe below, is the first to incorporate solar water. It is not the first, however, to utilize passive solar heat as supplemental heating when it's sunny and cold outside, not only for the greenhouse, but for the home.

With the new solar water system almost ready to fire up, around-the-clock warmth awaits us as the days get shorter and snow is inevitable. This will mean year-round gardening even to temperatures of -20°F, and with amazingly low energy usage.

Our solar greenhouse is a complete, full room that adds vibrant living space, winter heat, fresh air and indoor gardening possibilities to our home. It's a four-season room that one can relax in on a pleasant summer evening as well as a crisp winter morning. We're pleased with our progress so far and we want to share some tips from our experiences, including photos from all of our greenhouse adventures.


Structure of a Solar Greenhouse

We designed the greenhouse from scratch, including its 2-ft. by 4-ft. framing, vinyl and aluminum wraps, three sides of sliding glass doors and double French doors that open to the full basement. The roof was designed with a thermostatically opening vent. The sliding doors and custom-cut gable ends are tempered, insulated glass, while 25-mil polycarbonate forms the roof.

The exact dimensions of the greenhouse were determined by the widths of three sets of sliding glass doors plus the framing posts along the long side, and two sets of sliding glass doors and framing on the shorter ends.


An important tip: if you're using treated lumber, make sure to prime and seal-coat before wrapping with aluminum. Some of the new, treated lumber is less caustic but it's still a good idea to seal for potential corrosion of the aluminum. Find someone you trust to help out with framing if you're ever in doubt.

Floor for a Solar Greenhouse

A radiant floor heating system, using Pex tubing and a 1-in. thick foam board below for insulation, is in place below 4-in. concrete with black marble tiles that also absorb the warm winter sun. The system is connected to solar vacuum water tubes on the roof, solar water storage tanks in the basement, radiant floor heating in the rest of the basement, an attached garage, furnaces and a refitted hot tub.

Roof System for a Solar Greenhouse

The venting plexiglass roof system was designed to fit the dimensions of the structure and the rafters supporting it. The roof vent is controlled by an adjustable thermostat to keep heat in or let it out. We added two ceiling fans, mounted to the rafters, to not only circulate fresh air and heat flow when the French doors are open, but they look nice, too. There is a return air into the furnace system in the home that is thermodynamically driven, bringing in fresh heated air in the winter when needed.

Final Touches for Your Solar Greenhouse

There is, of course, a water faucet for easy plant watering. And just in case, there is also a convenient floor drain. We have done a lot of deep flood air injection in the past, which always tends to plug. The root systems will outgrow any system.


Happy experimenting! And building and don't forget how important solar and energy efficient designs are nowadays. Your greenhouse is a perfect place to experiment with nature, whether it's with your plants, the sun's heat or both.

It's a perfect way to help keep your energy bills in line, too, and with added fixtures, you too can outgrow nature's sunshine. You can turbo-charge nature's energy for enhanced production, efficiency and fun.


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Written by Charles Winslow

Profile Picture of Charles Winslow
Charles Winslow, CEO of GW Worldwide LLC, has a BS from Cal Poly. He has been principal in multiple start-ups and expansions including BWGS/Sunleaves, Penhall International, Furrows. He currently works with international companies developing JV’s, co-ventures, and new technologies for energy reduction for horticulture, lighting and building. Contact [email protected]

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