History of Hybrid Homes

1. Presents a series of Affordable Zero Energy Homes Homes with no utility bill that can also power a plug-in hybrid car

2. How it started : a friend of my mother’s bought into a subdivision. We visited it. I thought, how to design solar homes for all these lots?

3. Upon Reflection , it occurred to me that if we could design houses for the 8 points on the compass that we could then cookie-cutter in any subdivision. A name and a Logo ensued:

4. A potential investor suggested we consider putting together a Homeplans Catalog. We started researching existing home plans and worked up an executive summary:

6. One Home we did like, was that of a fellow local contractor who has remained an on going consultant. We felt the solar thermal was too complex and that the design could have been better integrated, but it was Zero Energy-quite a feat in our climate.

7. One feature we liked was the isolated sunspace, which was narrow and more of a collector than your classical lounge chair sunspace. The heat was circulated through the house using in-line duct Panasonic Whisperline Fans.

8. We also talked to NREL. We consulted with their Residential Division, about the insulation package for a house we were doing. They recommended a system that yielded an R-33 wall with standard materials and methods, close to SIPS at half the cost and equal or greater than an ICF wall.

9. We found no non- cardinal point designs . They intrigued us, so with a local architecture firm we worked up some conceptual designs - some for actual lots in the original subdivision.

11. On a camping trip, by the fire one night, the Vision came:

12. In that vision all essential components were embodied. A cost effective Building System was revealed:

13. A Key component was the Hybrid Truss . It gives the house a large south facing roof for a large photovoltaic array and an inexpensive second story space due to its prefabricated modular construction. Attic space Habitable Attic roughly 50% of main floor SF Photovoltaic Array

14. With Hybrid Homes architect Vern Seieroe, we embarked upon design of a prototype home. We realized the truss had many variations, which we had engineered. Its pitch could also vary. “ Max” Truss allows a maximum PV array Hybrid Truss with return-a more classical roof look Dormer Truss allows south windows with a Craftsman look “ Long Truss” for houses with Sunspace on the side

15. Our design was essentially a modified ranch home with a south side sunspace collector and an upstairs generated by the Hybrid Truss.

16. We embellished the entry side with a craftsman style porch and dubbed the house the N1, for north side entry version1

17. We obtained a Photovoltaic Bid. The design could accommodate a 24 KW system. With federal rebates and in Xcel electric territory, the cost of this system would be approximately $39,000, with a payback estimated at 11 years.

18. Note that ∆ is the difference between the Standard Home and the Home after the column. ∆ ∆ ∆ Cost to Own versus Cost to Buy: this Cost Analysis Chart compares a Standard Home with three levels of a Hybrid Home. The stronger the rebates the greater the economic advantage of a Hybrid Home.

19. The Economic Advantage is even greater with a longer term loan. Note the advantage in Xcel territory where even at today’s heating cost it makes sense to install the large PV system

20. We drew up NREL’S insulation scheme that involved simple framing and readily available products and methods:

21. We had this design energy modeled by George Scott and Associates. The results were impressive. The house with the sunspace and the insulation already achieved a HERS rating of 55.

22. Adding the PV Array, the HERS rating dropped to -55 !

25. . Plus, according to our engineer, the design generates enough energy to heat and run the house as well as power a plug-in hybrid car like the Nissan Leaf or Chevy Volt = NO GASOLINE BILL

26. In my mind one problem remained: how to transfer the heat from the ceiling of the sunspace to the thermal mass floor. We called this the Liquid Heat Transfer System. Conceptually it looks like this (orange line):

27. From a database of a sunspace collector, we know that the temperature at the ceiling generally exceeds 130 degrees on sunny days:

28. Our own calculations indicated an average gain of 244,000 BTU per day averaged for January-March:

29. After investigating various assemblies and products, and in consultation with NREL, we came up with a simple design that incorporated a fin tube into the air circulating system. The liquid would then be circulated into the concrete floors,

30. We sourced a Heating Engineer , recommended by a fin tube manufacturer. Given the previously stated conditions, he calculated that 25,000 BTU/hr would be transferred. Over a typical 6 hr solar gain period, that would result in 150,000 BTU’s transferred to the main floor slab or a temperature gain of approximately 4 degrees for 10 tons of concrete.

31. We modified the Heat transfer Diagram to include the Liquid Heat Transfer System: Liquid

32. We filed a Patent Application for the Hybrid truss and the Liquid Heat Transfer System.

33. No Cooling would typically be required. The photovoltaic array shades the south roof and the overhang of the sunspace blocks the summer sun. Additionally the east and west windows of the sunspace could be opened for ventilation. Also the house windows could be opened at night to cool the concrete thermal mass floors down to nighttime temperatures.

34. We realized that many Ranch Home Plans could be modified to a Hybrid Home, by adding a Sunspace Collector and the Hybrid Truss. Classical Ranch Floorplan “ Hybidized” with Sunspace and Hybrid Truss second story space

35. These houses could be small like the conversion of this 560SF ranch home, which, as configured, could be a duplex. We would love to build this for Habitat for Humanity: 560SF, 1 & 1/2 bedroom ranch Becomes a 1200SF two story Hybrid Home

36. We looked at many suitable properties and collected many standard ranch plans that could be modified. Scaling everything to 1/8” and cutting the plans out, we could readily find a plan for any property with suitable solar access. Some standard plans cut to 1/8” scale

37. Shown below is one of those plans dropped onto Lot 24 at Shadow Grass Estates in Longmont, CO:

38. The new Production Home of the future could be a slab on grade Ranch with an unfinished attic as opposed to the old ranch with an unfinished basement Fancier 3 bedroom ranch floor plan Adding a Sunspace to the side and the Hybrid Truss gives an attic space of approx. 880 SF

39. And Jeffrey’s best graphic mock-up of the front elevation for the previous house: Home Plans Rendering Modifying the roof with the Hybrid “Long Truss”. Entry etc. need architectural detailing (e.g.next slide)

40. Vern did better on a property that we liked. We developed a full schematic design for 1325 S. Kimbark in Longmont, CO:

41. The Main Floor was compact and versatile with a main floor flex room with its own entrance:

42. The second floor has a nice master suite and a second bedroom:

43. We envisioned an unfinished basement for future growth: Mechanical room

44. We worked up pricing. Realizing that our database was for custom homes, we consulted with local builders to fine tune our estimate:

45. We put together a proforma and talked to banks. We found that we would need investors to leverage the project.

46. Having had the vision of a novel product and developed it , we let go of the idea of a Home Plans Catalog. Instead we are focused on finding a property for a Demonstration Home aka Proof of Product. Our realtor is preparing an ad to source a presold home.

47. Our current objective :

49. Presents a series of Affordable Zero Energy Homes Homes with no utility bill that can also power a plug-in hybrid car