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Off-Grid Living: Innovative Elements of Passive Solar Design

Off-Grid Living: Innovative Elements of Passive Solar Design

 

Do you dream about living in a home that’s off-the-grid and energy efficient? You aren’t alone! Many environmentally and financially-minded consumers today are prioritizing energy and cost efficiency in their home buying or building. When it comes to saving money and achieving energy independence, off-grid, passive solar homes have been getting a lot of buzz.

Passive solar design has been around for centuries (check out this article on the history of passive solar) since people first learned to build their homes to take advantage of the sun’s position to trap heat in the winter and stay cool in the summer. The basic principles that were discovered thousands of years ago remain the same, but modern technology has improved upon these elements to ensure that today’s passive solar homes are more efficient than ever before.

The Basics of Passive Solar Design

Whether you’re building a new home from the ground up or renovating an existing structure with passive solar principles in mind, you’ll want to consider the following:

South-Facing Windows

In order to use the sun’s rays to heat your home (passive solar heating), you’ll need apertures (windows) that are appropriately placed to let the light in. In the northern hemisphere, this means that the majority of windows should be south-facing so they receive sunlight during the winter months when additional heat is needed. For best results, experts recommend that south-facing windows are positioned to receive direct sunlight from 9:00 am to 3:00 pm, drawing in warmth from the sun at its peak strength.

In a “direct gain” passive solar system, these windows will utilize 60-75% of the energy from the sun. Passive solar home-builders or renovators are advised to maximize southern exposure by elongating homes along the east-west axis.

Thermal Mass

While windows are positioned to let in the maximum amount of sunlight during winter months, that energy must be stored somewhere in order to sustain heat throughout the evening and night. The second half of the equation is thermal mass materials which have the capacity to absorb, store, and distribute heat energy from the sun. Material with thermal mass have innate qualities that support both heating and cooling - popular examples include masonry walls, concrete floors, ceramic tiles, and water containers.

When the sun strikes these components during the winter months, they will absorb heat and radiate it to continue heating the home after the sun has set. In the summer, when kept out of the sun, the high density of these materials keeps them cold and provides a cooling effect.

Shading or Controls

The final components of an effective passive solar heating and/or cooling design are the controls that can be used to increase or decrease sun exposure. These can include landscaping features such as shade trees or berms around the north, east, and west of the home, as well as awnings, overhangs, or shutters that can be adjusted to block the sun during the summer heat. Because of generally higher sun angles during the summer, experts can recommend overhangs or angled roofs that admit the sun’s rays during winter but block them in the summer. This Sun Calculator can help you get an idea of the angle of the sun in your location.

Adding “Active Solar”!

The principles of passive solar design for heating and cooling aren’t new, but technological advances now allow homeowners to not only limit their dependence on outside energy providers but to erase it entirely. A passive solar home with active solar components can direct the sun’s energy to heat or cool a home and also provide for its additional energy needs such as lighting, appliances, and more.

Active solar design includes the use of photovoltaic solar panels to collect and store energy, either by heating liquid or air, or modern electronic systems connected to battery storage (check out our article on Solar + Storage). Adding solar panels to a passive solar home doesn’t impact the home’s ability to heat and cool itself, but replaces grid-dependent energy systems to provide a truly off-grid, energy independent lifestyle. That’s why many passive solar designs today include solar panels or other alternative energy sources.

The Financial Value of Passive Solar Design

Passive solar homeowners eliminate many expenses and utility costs associated with home ownership and greatly increase the rewards of their investment in their home. By cutting the cord from utility companies and producing and storing their own energy, homeowners can achieve true energy independence and save money at the same time.

My wife and I are in the process of building a passive home on our small farm in Platte County, MO. The home, which is currently under construction, will include a very affordable off-grid Solar PV system in addition to many of the passive solar design principles discussed in this and previous articles. Contact us for access to a Facebook page where you can view our construction approach and progress as well as a financial assessment detailing how we’ve made our project more affordable than others.

At Solar Design Studio, we understand the many options that are available to home or other property owners and guide them through the planning and decision-making process to ensure that they get the most out of their solar energy investment. If you have questions for our solar experts, contact us today to start your journey toward solar-powered living.

 

 

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What Our Clients Are Saying

I have researched adding PV to my home for several years and have met with several PV providers in the KC area and they tend to fall into two broad categories, the new and low budget operators who got into this to ride the wave and are not that knowledgeable, and the commercial providers who have little interest in working with a homeowner and are geared to providing a much larger system where some economy of scale must come into play. Both my wife and I are architects and we wanted something different and it was challenging to find someone who was interested in doing something out of the ordinary. Neither or those types were interested in working with us as we were trying to create something a bit different. they each wanted to sell us their pre-configured solutions.

 

Fortunately we found Bob Solger. He has been a delight to work with and is incredibly knowledgeable and responsive. We wanted to create a solar carport that would provide cover and protection for our cars, but would also provide shade over part of our patio. In essence, the big idea was to create an outdoor pavilion, when, if we wanted to entertain we could move the cars out of the way and have a large covered area for an outdoor gathering. We had selected the Lumos brand of solar panels as they have a very clean look and are partially transparent so some light filters through the panels creating a mottled light pattern on the ground, similar to the shading from a tree. In addition, the system is set up to hide the majority of the connecting wires in the support beams so when you look up at the underside of the PV roof you see a very clean look. Bob recognized our goal and worked with us to ensure the project’s success. Bob identified a structural engineer to design an elegant support structure and found a fabricator to build it affordably. Finally he connected us with a contracting team to clear the space, provide the footings, retaining walls, and pad, who were every bit as careful with everything as you would hope. They were amazingly accommodating to every request and understood that there were a lot of competing challenges that needed to be resolved so we could fit this all in to a very tight location and make it look like it belongs.

 

The bottom line is that it all turned out better than we could have hoped and while it did cost more than the low ball bids received from some of the low budget operators, it was less than the commercially focused suppliers, and more importantly we got the design we wanted and a well-constructed PV carport that will give us great delight for years to come. The best part is of course the savings on our electric bill, which thus far has been averaging around $200/month. So not only do we have a new carport and entertainment patio that our neighbors have been stopping by and admiring (which given that we live in the older Brookside neighborhood and our PV carport is quite modern, we were much relieved) but, our electric bills have been in the under $10/month range.

 

We owe a great debt of gratitude to Bob and his knowledge and team for helping to create an amazing PV carport for us. I’m sure you would be delighted with whatever you engage him to help you with.

Dev & Sue Malik

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