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Building Science

A Classic 1970s Home Goes from Solar-Heated to Net Zero Energy

Richard Levine’s Raven Run house in Kentucky has evolved over the decades

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Designed, built, and lived in by Richard Levine (standing in foreground), the Raven Run Solar House near Lexington, Kentucky is a nice example of a classic active solar house from the 1970s that has served its purpose well and evolved over time.
Image Credit: Energy Vanguard
Designed, built, and lived in by Richard Levine (standing in foreground), the Raven Run Solar House near Lexington, Kentucky is a nice example of a classic active solar house from the 1970s that has served its purpose well and evolved over time.
Image Credit: Energy Vanguard
The original solar collector controller for Levine's house sits in the basement now.
Image Credit: Energy Vanguard
This Clivus Multrum composting toilet has been in service for nearly four decades.
Image Credit: Energy Vanguard
These photovoltaic modules have turned the Raven Run Solar House into a net zero energy house.
Image Credit: Energy Vanguard

Last week I was in Lexington, Kentucky speaking at the Midwest Residential Energy Conference. It was a great regional conference, and the folks there are making things happen. (I even played nice. With all those Kentucky Wildcat fans there, I held back and didn’t mention in any of my talks that I’m a Florida Gator.) One of the many highlights for me was getting to visit Richard Levine’s 1970s active solar house. It stands out like no other house I’ve seen, and I’ve seen other solar houses.

Your first question upon seeing the photo here might be, “Is that really a house?” Yup. He chose the shape to maximize solar gain while minimizing the area of the building enclosure. It’s a cube sliced on the diagonal, which you can see in Part 1 of the video series below. (That part starts at about the 3:30 mark.)

The Raven Run Solar House

The creek that runs in the ravine near the house is called Raven Run, so the house is called the Raven Run Solar House. Levine designed and built it in 1974-75, one of the earlier solar houses built as a result of the energy crises of the ’70s. Martin Holladay has done a great job covering the history of solar-heated and superinsulated houses in North America. (See Solar Versus Superinsulation: A 30-Year-Old Debate and The History of Superinsulated Houses in North America.) He contends that superinsulation won because most solar houses overheated on sunny days and froze people out on cold nights.

Holladay may be right overall, but Levine’s home is a great example of a solar home that has performed well. It didn’t overheat because he stored heat in the rock beds below and could vent excess heat out the top when necessary. His main problem was humidity that went a bit too high in summer because passive cooling doesn’t deal with the water vapor in the air.

Here’s a quick rundown of a few of the cool features, including what he eventually did about the summer humidity:

Solar collector for space heating. What you see in the photo above is not all windows dumping massive quantities of sunlight into the living space. Some of them are windows, and some are a special type of solar collector that he designed and patented. Each column of collector glazing has corrugated aluminum behind it, and as the air heats up, it rises naturally. The solar gain on those columns of air can provide up to a 100 degree Fahrenheit rise in temperature.

But he’s doing more than just using the stack effect. He designed a system that uses a fan to move the hot air from the top of each column down to rock beds in the basement, where the heat gets stored. When it’s cloudy, he can draw heat out of the rock beds for two weeks. It’s a pretty sophisticated system, and he’s avoided turning the rock beds into a mold factory. One of the photos below shows the original controller for it, which is no longer in use.

Composting toilet. The house has had a Clivus Multrum composting toilet since the beginning. Having built and lived in a house with a composting toilet myself, I get it. Many people don’t, however, especially if it means sitting over a big open hole straight to the tank in the basement. But think of all the water he’s saved by never having to flush a toilet in his home for four decades! In the second photo below, you can see the tank in the basement and the access door through which you remove the composted material.

Net zero energy. A few years ago, Levine installed photovoltaic modules on the studio adjacent to the house. Because of the cold winter this year, he hasn’t been net zero in his energy balance between consumption and production over the past year, but he was for the two years before that.

Other updates. Levine recently installed a heat-pump water heater and a decade or so ago had a ground-source heat pump put in. The latter was mainly to get cooling with dehumidification. He had relied on natural cooling for a long time but finally decided that the humidity issue warranted a mechanical air conditioning system.

I didn’t get to spend a lot of time there, but it’s exciting to see that a classic solar-heated house from the 1970s — and one of the earliest ones, at that — has not only survived, but has served its purpose well and evolved gracefully over time.

Levine is a new board member for the Passive House Institute U.S. (PHIUS), as am I, so I look forward to working with him. He brings a wealth of knowledge, experience, and ideas, which will help immensely as we take this movement further down the road to more sustainable buildings.

Other resources

CSC Design Studio page on the Raven Run Residence. CSC Design Studio is Levine’s architecture firm in Kentucky.

Richard Levine’s page on Wikipedia

Four-part video series on Levine and his work by

Part 1

Part 2

Part 3

Part 4

Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.


  1. GBA Editor
    Martin Holladay | | #1

    Solar air systems
    Thanks for profiling this classic house.

    Many researchers have investigated the performance of active solar air systems with rock bin storage. For a comprehensive overview of this type of active solar space heating system, see my December 2004 article from Energy Design Update, Solar Air Systems: Not Dead Yet. (The article begins on the bottom of page 8.)

    My article discusses several long-lived solar air systems, including the one at George Löf's house in Colorado -- tragically demolished in 2013 -- and the one at Robert Reid's house in Knoxville, Tennessee.

  2. PWiyZXRHbr | | #2

    Richard Levine
    Not long after joining the staff of Fine Homebuilding magazine in 1981, I found myself in Lexington to do a story on Richard Levine's solar home. It's very encouraging to see that the house has evolved, and to learn that the architect is still advocating for energy efficiency. We've come a long way since those early days, when design attention focused more on solar gain than on building envelope improvements. I continue to believe that innovating for energy efficiency represents one of our greatest leadership (and job creation) opportunities in the U.S. I hope I'm right.

  3. GBA Editor
    Martin Holladay | | #3

    Fine Homebuilding article
    Here is a link to Tim Snyder's article from 1983: A Slice Off the Cube.

  4. kevin_in_denver | | #4

    Historic Preservation
    Without protection, this house will get scraped just like George's.

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