The Rain Shine House

Decatur, USA

Robert M. Cain, Architect
www. robertmca і n. com

The State of Georgia in the South Eastern United States enjoys a humid, subtropical climate. In winter, occasional polar air masses can bring cooler weather, however, Georgia is characterised by its typically hot and humid summers. The State can be affected by neighbouring Florida’s hurricane season. The hurricanes tend to weaken overland, becoming tropical storms of heavy rain and strong winds.

Average rainfall is moderate to heavy, varying from 45 inches in the central state to 75 inches in the mountainous northern part of Georgia.

Georgia’s state motto “Wisdom, Justice, Moderation” may well have been applied in bringing the RainShine House project to fruition. The challenge for architect, Robert M. Cain, was to design and construct a customised, sustainable home on a l/3rd acre plot with a constrained
buildable area. The plot, located close to downtown Decatur, was blighted by a man-made flood plain. Inadequate municipal culvert design, run off from a nearby parking area and a sewer easement dictated that the building area would be a trapezoidal shape totalling 3,778 square feet. However, the client’s lifestyle choice of walking, cycling and enjoyment of the daily opportunities afforded by Decatur’s diverse community culture could all be realised from this problematic plot. The challenges were addressed directly by orientating the open aspects of the house towards the open space afforded by the easement and the stream’s buffer requirement.

The customised use of floor space is illustrated on the architect’s drawings (Figs. 3, 4, 5, 6).

216 The RainShine House | Decatur | USA | Fig. 1 above | Fig. 2 opposite

Fig. 5 above I Fig. 6 below

The most striking design feature of RainShine House is the inverted shape of the roof (Fig. 2), (Fig. 5), likened to that of a butterfly’s wings. This roof shape facilitates the capture of rainfall (Rain) and virtually eliminates the need for high maintenance gutter and fall-pipe systems. The captured water is stored in 5 x 500 gallon cisterns located in the basement of the house. The roof is oriented to the south, maximising the efficiency of a 3.1 kW, roof-mounted, photovoltaic system (Shine). The long roof spans are supported by a framework, locally fabricated from 100% recycled content steel (Fig. 9).

Further contributions to the property’s energy efficiency include geothermal heat pumps, energy recovery of the naturally cross-ventilated spaces and LED lighting systems. All household appliances were selected on the basis of energy efficiency. The facade glazing is designed to minimise solar gain.

Cost Projections:


$ cost / year

Annual Heating



Annual Cooling



Hot Water






Household Appliances



Energy Recovery Ventilator 810


Rain Water Harvesting.



Architect Robert M. Cain provides the following Energy

Gross Total** 13,301 $1,419.27

Photovoltaic Production * 7,500 -$1,330.50

Nett Energy Consumption 5,801.5

** Georgia av’ Sept 08 rate per kW/h 0.1067 * Georgia Power nett meter rate per kW/h 0.1774 Total Cost per year $88.77

Monitoring in June, July 2009 verifies the estimates.

RainShine House achieved Leed platinum for Homes

Platinum Threshold (points) 97

Sustainable sites 20/21

Location and linkages 8/10

Water efficiency 14/15

Energy and Atmosphere 29/38

Materials and Resources 12/14

Indoor Environmental Quality 14/20

Innovation and Design 9/9

Awareness and Education 2/3

Total Points Achieved 108

220 The RainShine House | Decatur | USA | Fig. 7 above | Fig. 8 below