that might have otherwise been spared. That left us with a rather bleak picture, and took most of our privacy away. We took heart in the knowledge that Mark, our builder, had recycled all of the cut wood to the lumber mill, for mulch, pulpwood and lumber. I believe that is part of the EarthCraft building guidelines. In looking at the back of the cleared lot, and thinking of how to gain some privacy without creating problem shading, I realized that in the future there may be a place for solar-sensitive landscape design (ie. now what can I plant back there that will provide cover and not grow more than about 15 feet high?).Wednesday, March 31, 2010
Wow.. it's going to really happen!!
Seeing the cleared lot offered a stark example of the application of the theory of unintended consequences combined with the principle of compromise. We knew that to get adequate solar exposure to our PV array mounted on the garage roof, that we would need to take most of the trees down. We positioned the array on the lot to maximize solar exposure, but it still required that we clear most of the mature oaks 
that might have otherwise been spared. That left us with a rather bleak picture, and took most of our privacy away. We took heart in the knowledge that Mark, our builder, had recycled all of the cut wood to the lumber mill, for mulch, pulpwood and lumber. I believe that is part of the EarthCraft building guidelines. In looking at the back of the cleared lot, and thinking of how to gain some privacy without creating problem shading, I realized that in the future there may be a place for solar-sensitive landscape design (ie. now what can I plant back there that will provide cover and not grow more than about 15 feet high?).
that might have otherwise been spared. That left us with a rather bleak picture, and took most of our privacy away. We took heart in the knowledge that Mark, our builder, had recycled all of the cut wood to the lumber mill, for mulch, pulpwood and lumber. I believe that is part of the EarthCraft building guidelines. In looking at the back of the cleared lot, and thinking of how to gain some privacy without creating problem shading, I realized that in the future there may be a place for solar-sensitive landscape design (ie. now what can I plant back there that will provide cover and not grow more than about 15 feet high?).
Saturday, March 27, 2010
ZEH: it's a system
In 1990 we built what was for its time, an energy efficient, all brick home. It included some 6 inch walls, extra insulation, a Lennox pulse gas furnace, low-flow toilets (they are forever clogging), low-E windows, and south facing glass. The rumor around our Richmond neighborhood was that we were from Vermont, and did not know how to build for the more temperate climate. Fast forward 20 or so years. My wife found a lot with river access closer to her office, so it's time for an encore, to build our single level (out of deference to aging knees) "retirement" home. Out of concern for the generations to come, for minimizing monthly bills and for an outlet for our creative expression, the notion of building a zero energy home (ZEH) emerged. After a bit of study, it becomes clear that a ZEH is not a single feature or advantage, but rather a set of complementary features which form an efficient system. That sytem consists of creating a home with a tight, well insulated envelope, minimizing the energy loads in that envelope, and adding a renewable energy source. Sounds simple, but as you move forwards it gets complicated quickly. In an email to a interested relative, I described the basics of our proposed ZEH as:
...it is basically designed as a single story home, with some bonus rooms upstairs...it will be all brick with a semi-detached garage (the why of that comes later)...the walls will be R16 and the attic R38...the walls will use wet spray cellulose and the attic loose cellulose...a conditioned crawl space...we are also using a new product on the outside of the stud walls, Dow Styrofoam SIS, (structural insulated sheathing) which will be taped, forming an air/vapor barrier, an extra layer of insulation, a shield against thermal bridging of the studs, and a structural element...pretty cool...with respect to the R levels, they are more than sufficient for our climate, as the wet spray cellulose significantly increases the thermal mass of the house... along with the tightness of the house (we aim for less than a .20 Natural Air Exchanges per Hour blower door result and a less than 4% of floor area served leakage to outside duct test result; an ERV will be installed for ventilation), the increased thermal mass may even eliminate the need for a setback thermostat, as the temperature of the house should remain incredibly stable...we are going to look into cool roofs/radiant heat barriers, but setting up the heating/coolng "firewall" at the attic floor may be more cost effective....
...we are looking at double pane, vinyl clad, low E, argon windows, with U value of .33 and SHGC of.30...we are looking into a new model with a U below .30, getting a price difference on that...
...Caroma (the reviews say they never clog) 1.28/0.8 dual flush toilets to save water...
...the HVAC system is proposed to be a Comfortaire GeoMax2 geothermal heat pump of 4 ton capacity with desuperheater rated @ 23.7/16.6 EER & 4.0 COP...hot water will be pre-heated by the desuperheater and then go to a 98% efficient Navien tankless condensing water heater with a built in recirculation pump & mini buffer tank for a digital timer controlled recirculation loop to prevent the dreaded "cold water sandwich" you can get with tankless water heaters...the solar grid-connected PVC array will consist of 20 Schuco Monocrystalline 210 panels (4.2kW) and a SunnyBoy inverter mounted on a true south oriented garage roof...
We will begin to look at each of these features as the build progresses, analyzing their benefits and potential assets and seeing how they may complement (and hopefully not compromise) the "system". Stay tuned.
...it is basically designed as a single story home, with some bonus rooms upstairs...it will be all brick with a semi-detached garage (the why of that comes later)...the walls will be R16 and the attic R38...the walls will use wet spray cellulose and the attic loose cellulose...a conditioned crawl space...we are also using a new product on the outside of the stud walls, Dow Styrofoam SIS, (structural insulated sheathing) which will be taped, forming an air/vapor barrier, an extra layer of insulation, a shield against thermal bridging of the studs, and a structural element...pretty cool...with respect to the R levels, they are more than sufficient for our climate, as the wet spray cellulose significantly increases the thermal mass of the house... along with the tightness of the house (we aim for less than a .20 Natural Air Exchanges per Hour blower door result and a less than 4% of floor area served leakage to outside duct test result; an ERV will be installed for ventilation), the increased thermal mass may even eliminate the need for a setback thermostat, as the temperature of the house should remain incredibly stable...we are going to look into cool roofs/radiant heat barriers, but setting up the heating/coolng "firewall" at the attic floor may be more cost effective....
...we are looking at double pane, vinyl clad, low E, argon windows, with U value of .33 and SHGC of.30...we are looking into a new model with a U below .30, getting a price difference on that...
...Caroma (the reviews say they never clog) 1.28/0.8 dual flush toilets to save water...
...the HVAC system is proposed to be a Comfortaire GeoMax2 geothermal heat pump of 4 ton capacity with desuperheater rated @ 23.7/16.6 EER & 4.0 COP...hot water will be pre-heated by the desuperheater and then go to a 98% efficient Navien tankless condensing water heater with a built in recirculation pump & mini buffer tank for a digital timer controlled recirculation loop to prevent the dreaded "cold water sandwich" you can get with tankless water heaters...the solar grid-connected PVC array will consist of 20 Schuco Monocrystalline 210 panels (4.2kW) and a SunnyBoy inverter mounted on a true south oriented garage roof...
We will begin to look at each of these features as the build progresses, analyzing their benefits and potential assets and seeing how they may complement (and hopefully not compromise) the "system". Stay tuned.
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