Energy Design

This prototype home was designed to be as energy efficient as possible without the initial addition of alternative/renewable energy systems. Many of the very educated and experienced green building professionals that I talked to prior to construction of this home were sceptical that this home could achieve such high performance without the addition of systems like geothermal, solar thermal, and or passive solar design with thermal mass. Although I am a proponent of all these technologies, many consumers, GC's, subcontractors, real estate agents, appraisers, and lending professionals either don't understand them, can't accurately value them, can't afford them, or maybe just don't care. In a much earlier post, I wrote that the most important aspects of affordable high performance homes are proper planning, understanding orientation to the sun, shade and wind, a well insulated building envelope, a well sealed building envelope, a properly sized and installed HVAC system and a whole house mechanical ventilation system (ERV for this climate zone). This prototype is estimated to reduce energy costs by at least 60% and the fact that I am a very energy conscious individual, it should exceed 60%. A 60% + reduction in energy costs, combined with a very healthy and strong home at less than $105 per square foot is definitely within reach of so many more people in our communities.

As I've mentioned in previous posts, this prototype was originally designed to be built on a fully insulated slab on grade for thermal mass purposes and reduction in costs. The concrete can absorb the winter sun and then release it back into the conditioned space when the temperature starts to fall. This can be a very simple, cost effective energy saving solution when available. I decided to build on a crawl space as the lot was more suited for this and as the picture shows, I used an R 4.5 Demilac spray foam in between the floor joists and also on the bands. The picture also shows a dehumidifier that has a drain hose to the outside. This keeps the ambient humidity at a constant level reducing the concerns of mold and mildew problems. Please remember to use a quality vapor retarder (not vapor barrier) on the floor as this can make a significant difference in controling the humidity level. I also spent extra time sealing the crawl space in order to have more control over the humidity level and air infiltration. Also pictured is the new GE GeoSpring Hybrid Hot Water Heat Pump. Compared to traditional hot water tanks with a energy factor as high as .95, this GE hot water heater has an energy factor of 2.35--almost 2.5x more efficient. For me this was a much more cost effective alternative to solar thermal hot water systems. The main drawback of this system is that it can make some noise, very similar to an outdoor compressor unit of a traditional heat pump system. With the door shut and some weather-stripping it is much less noticable. More posts to follow.