Trail Magic
A Positive Energy Home
General Process
Schematic design was created by Donald Watson, FAIA, who had been dean of architecture at Rensselaer Polytechnic Institute where I taught and who lives in Trumbull, CT. He asked us what our budget was and to describe in general the house we wanted him to design, the rooms to be in the house, how each room would be used, and the furniture to be in the room. We provided Watson with an owner's program that underwent 4 iterations, the first being 3 single spaced pages and the final version had 7 pages. We started with a rectangular house of two floors (3,600 sq. ft.), no basement or attic. Over 6 months he presented us with a sequence of floor plans that started with 2 floors and 3,000 sq. ft., and ended with 2 floors and a dormer totaling 2,500 sq. ft. (external dimensions). The schematic design was completed and handed off to Joe Ferut, a local architect in NE Ohio, who did the detailed design and oversaw the project.
Ferut with our assistance put Watson's schematic design plans out to 5 builders for bids. We were attempting to conform to LEED platinum standards although no builders in NE Ohio were LEED certified and the LEED homes program was in the pilot phase. One builder withdrew because he couldn't do the research to bid on a house conforming to LEED standards. Mike Strehle of All Seasons Builders, a small house building firm, wanted to learn about LEED and submitted the lowest and most thorough bid. Although he was only 31 years old, his quiet, calm, can-do personality made him an ideal team member for our innovative project. Our team had a talented, knowledgeable group that worked well with each other and subcontractors: Donald Watson, Joe Ferut, David Borton [PhD solar heat transfer physicist], Mike Strehle, my wife, and myself [PhD biologist]). Each member participated intimately in all aspects of the design and construction processes with the agreed upon goals of building a quality, high performance, passive-active solar house that would be positive-energy and climate-positive. This commitment was discussed with all sub-contractors who were encouraged to engage with achieving these goals.
Design for Adaptability: Our goals were to build a house 1) of high performance that ran on sunshine and 2) of high quality that would require low maintenance and that would be sufficiently durable to be habitable for perhaps 100 years. Trail Magic had a 24-gauge raised-seam metal roof, prepainted Hardi Board siding, Loewen windows, extreme insulation (slab: R 20, ground floor walls: R 35.5, above ground walls: R 47.5, and roof: R 62.5), quartz kitchen counters, hardwood floors, hard wood bookcases and shelves, and other quality materials required for a long lived house.
Software Tools
Software Tools:
General modeling information: Joe Ferut and a building engineer ran heating and cooling models that were used to compare heating and cooling systems, and then for selecting the heat pump and determining the capacity of the pond loop.
Lessons Learned
Outcome of project goals: Eight years of data on energy use and production as well data on water and hot water use definitively establish that we achieved a high performance home that runs on sunshine, has no energy bill, exports a significant amount of electricity to the grid, and is therefore a positive-energy and climate-positive home. The quality of living in a passive solar home is excellent, especially the quantity and quality of lighting, even during cloudy winters in NE Ohio.
We made one serious error. We should have made two heating and cooling zones. Zone 1, ground floor. Zone 2, first floor and dormer. For us it is not an issue except when we have guest in winter when that space needs to be heated making use of the wood stove not possible because the first floor and dormer get too hot.
We have had several equipment failures and replacements.
1. The programable thermostat failed and was replaced after 4 years.
2. The electric on-demand hot water heater had a design flaw that led to corrosion and failure of the control board. It was replaced after 7 years with a Stiebel, Tempra 20 B.
3. The evacuated tube solar hot water system proved to be inappropriate for domestic hot water heating because only 1% of the energy acquired was in the hot water used. It was removed after 2 years and replaced with a second PV system rated at 2.04 kW. The basic physics of hot water heating clearly establish this technology to be inappropriate for residential hot-water heating. Annually we use 2,500 gallons of hot water. The on-demand electric hot-water heater uses about 0.12 kWh/gallon to raise water temperature to 111 degrees F. Thus, 300 kWh are used per year for heating 2,500 gallons, or $30 at $0.10 per kWh. Even if 10 times this amount of hot water was used, the annual cost would only be $300. The evacuated tube system cost $6,500 while the on-demand hot water heater cost $800. Thus, heating hot water with an on-demand hot-water heater is 12% of the cost to heat with an evacuated-tube hot-water system.
4. The Carrier heat pump had a problem with heating after 6 years that required visits from the two service companies that installed the heat pump and the pond loop to correct the problem that apparently resulted from a design issue in the heat pump.
Discrepancies: Yes, predicted energy performance of Trail Magic was better than estimated. We predicted, based on energy use in our previous house, that we would use ~3,200 kWh or 100% of the expected production from our existing 3.12 kW PV system. We were keen on using less than 3,200 kWh and were careful not to waste electricity. In the first year we used 2,279 kWh and made 3,192 kWh. We have added a plug-in Prius hybrid (~650 kWh/year) as well as replaced the evacuated tube hot water system with a second, 2.04 kW PV system. We also eased back a bit and now annually use ~3,300 kWh and produce ~5,200 kWh. Our local utility does not compensate for electricity sent to the grid, but they do not justify production and use annually. On November 1, 2016, we had 12,950 kWh in the local grid "energy bank" that can be used if needed in the future.
General Process
Schematic design was created by Donald Watson, FAIA, who had been dean of architecture at Rensselaer Polytechnic Institute where I taught and who lives in Trumbull, CT. He asked us what our budget was and to describe in general the house we wanted him to design, the rooms to be in the house, how each room would be used, and the furniture to be in the room. We provided Watson with an owner's program that underwent 4 iterations, the first being 3 single spaced pages and the final version had 7 pages. We started with a rectangular house of two floors (3,600 sq. ft.), no basement or attic. Over 6 months he presented us with a sequence of floor plans that started with 2 floors and 3,000 sq. ft., and ended with 2 floors and a dormer totaling 2,500 sq. ft. (external dimensions). The schematic design was completed and handed off to Joe Ferut, a local architect in NE Ohio, who did the detailed design and oversaw the project.
Ferut with our assistance put Watson's schematic design plans out to 5 builders for bids. We were attempting to conform to LEED platinum standards although no builders in NE Ohio were LEED certified and the LEED homes program was in the pilot phase. One builder withdrew because he couldn't do the research to bid on a house conforming to LEED standards. Mike Strehle of All Seasons Builders, a small house building firm, wanted to learn about LEED and submitted the lowest and most thorough bid. Although he was only 31 years old, his quiet, calm, can-do personality made him an ideal team member for our innovative project. Our team had a talented, knowledgeable group that worked well with each other and subcontractors: Donald Watson, Joe Ferut, David Borton [PhD solar heat transfer physicist], Mike Strehle, my wife, and myself [PhD biologist]). Each member participated intimately in all aspects of the design and construction processes with the agreed upon goals of building a quality, high performance, passive-active solar house that would be positive-energy and climate-positive. This commitment was discussed with all sub-contractors who were encouraged to engage with achieving these goals.
Our goals were to build a house 1) of high performance that ran on sunshine and 2) of high quality that would require low maintenance and that would be sufficiently durable to be habitable for perhaps 100 years. Trail Magic had a 24-gauge raised-seam metal roof, prepainted Hardi Board siding, Loewen windows, extreme insulation (slab: R 20, ground floor walls: R 35.5, above ground walls: R 47.5, and roof: R 62.5), quartz kitchen counters, hardwood floors, hard wood bookcases and shelves, and other quality materials required for a long lived house.
Software Tools
Joe Ferut and a building engineer ran heating and cooling models that were used to compare heating and cooling systems, and then for selecting the heat pump and determining the capacity of the pond loop.
Lessons Learned
Eight years of data on energy use and production as well data on water and hot water use definitively establish that we achieved a high performance home that runs on sunshine, has no energy bill, exports a significant amount of electricity to the grid, and is therefore a positive-energy and climate-positive home. The quality of living in a passive solar home is excellent, especially the quantity and quality of lighting, even during cloudy winters in NE Ohio.
We made one serious error. We should have made two heating and cooling zones. Zone 1, ground floor. Zone 2, first floor and dormer. For us it is not an issue except when we have guest in winter when that space needs to be heated making use of the wood stove not possible because the first floor and dormer get too hot.
We have had several equipment failures and replacements.
1. The programable thermostat failed and was replaced after 4 years.
2. The electric on-demand hot water heater had a design flaw that led to corrosion and failure of the control board. It was replaced after 7 years with a Stiebel, Tempra 20 B.
3. The evacuated tube solar hot water system proved to be inappropriate for domestic hot water heating because only 1% of the energy acquired was in the hot water used. It was removed after 2 years and replaced with a second PV system rated at 2.04 kW. The basic physics of hot water heating clearly establish this technology to be inappropriate for residential hot-water heating. Annually we use 2,500 gallons of hot water. The on-demand electric hot-water heater uses about 0.12 kWh/gallon to raise water temperature to 111 degrees F. Thus, 300 kWh are used per year for heating 2,500 gallons, or $30 at $0.10 per kWh. Even if 10 times this amount of hot water was used, the annual cost would only be $300. The evacuated tube system cost $6,500 while the on-demand hot water heater cost $800. Thus, heating hot water with an on-demand hot-water heater is 12% of the cost to heat with an evacuated-tube hot-water system.
4. The Carrier heat pump had a problem with heating after 6 years that required visits from the two service companies that installed the heat pump and the pond loop to correct the problem that apparently resulted from a design issue in the heat pump.
Yes, predicted energy performance of Trail Magic was better than estimated. We predicted, based on energy use in our previous house, that we would use ~3,200 kWh or 100% of the expected production from our existing 3.12 kW PV system. We were keen on using less than 3,200 kWh and were careful not to waste electricity. In the first year we used 2,279 kWh and made 3,192 kWh. We have added a plug-in Prius hybrid (~650 kWh/year) as well as replaced the evacuated tube hot water system with a second, 2.04 kW PV system. We also eased back a bit and now annually use ~3,300 kWh and produce ~5,200 kWh. Our local utility does not compensate for electricity sent to the grid, but they do not justify production and use annually. On November 1, 2016, we had 12,950 kWh in the local grid "energy bank" that can be used if needed in the future.