Nick Pine's State of the Art Home Heating Sunspace

This is a description of Nick Pine's new cutting edge sunspace design and build.


The sunspace is three stories tall and is designed to provide substantial space heating for the home it is attached to. 

This is a new design with innovations in glazing, air distribution, and heat loss control -- some great new ideas to learn about and use.

There is a comments/questions at the end if you want to participate in taking this design further, or have questions about applying some of its elements to your sunspace. 

Thanks very much to Nick for providing the story on this exceptional sunspace!

The Story From Nick

large space heating attached sunspace  sunspce top floor 

This sunspace is 12' deep and 32' long and 28' tall. 

The end walls are twinwall polycarbonate, and the roof is 2 single layers of corrugated roofing polycarbonate. 

The south wall has 4'x8' double-glazed panels with 2 layers of 10 mil HP92W clear flat polycarbonate with eight 2'x4' operable vent panels at the top. Each glazing panel is gently inflated with welding argon via a tire valve.

Tthe materials for each 4'x8' site-built glazing panel cost about $100, and the double glazing has 85% solar transmission, vs $560 and 63% for a 4'x8' insulated glass Home Depot fixed window with a lot more wood and a lot less glass. The two 10 mil polycarbonate layers are squeezed by a ripped 2x4 frame in these panels. I wanted to just bolt the 2x4s into an integral modular structure with no extra studs, but my builder friend Marcus Sadler insisted on 24' 2x6 studs on 4' centers.

The deck in is 8'x32', 16' above the ground. The corrugations in the top layer of polycarbonate run north and south and match the metal roof corrugations. The corrugations in the layer beneath it run east and west.

Warm sunspace air enters an attic duct through holes above the central pair of 4'x8' doors.

Mesh Inside Glazing Improves Performance

Click on images for full size

sunspace south wall mesh sinspace radiation mesh

A mesh curtain with 2 layers of 50% black greenhouse shadecloth keeps cool house air near the glazing and blocks some radiation from the dark insulated house wall to the glazing and makes the sunspace more private and comfortable. 

The house air is only heated as it passes from south to north through the mesh.

Fran and Stephanie (right picture above), who used to drive a Caterpillar D9 bulldozer.

Installing sunspace south wall mesh
Stapling the shadecloth layers together
sunspace south wall mesh
After adding a layer of Scotts weed barrier, which didn't
last long in the sun and heat (over 130 F in December.)

Air Distribution System

sunspace air supply trench  air trench 

sunspace air trench   

These trenches carry cool house air from the basement to two floor outlets between the shadecloth and the glazing.

Builder Marcus overdid them and put the wood thermal mass on the wrong side of (the inside of) the insulation.
In retrospect, deheading 4 55 gallon steel drums and laying them end-to-end inside each trench inside plastic film would have been easier.


Performance -- What worked, What Didn't, Suggestions for Future Designs

My 1820 stone farmhouse has stone walls with 2" of sprayed foam on the outside and 6" of fiberglass outside that, but it's air-leaky, with about 10 gpm of groundwater sucking heat out of the lower part of the walls, so this sunspace has a hard time keeping the house warm when it's less than 20 F outdoors.

We used butyl rubber tape to seal the flat polycarb layers, and it has partially melted in high temperatures. Silicone caulk or strips of EPDM rubber might have worked better.

January 21, 2013

Nick in sunspace
The solar guru absorbing rays.


Comments and Questions

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