Siding and Trim

The siding used on this prototype home is pre-painted NichiHa fiber cement lap siding. The shakes are a pre-stained Western Red Ceder, the tongue and groove pine is Blue Stain Pine and the trim is Miratec. All of these exterior finish products were purchased through an Asheville company--Carolina Colortones. Carolina Colortones offers the best selection of siding options in the Asheville area and specializes in pre-painted and pre-stained exterior finish products. My experience working with Carolina Colortones was excellent. I chose the NichiHa product for several reasons. NichiHa products contain over 50% fly ash, a recycled content material generated from coal burning power plants. Not only does this material not end up in a landfill, but in my research it ends up creating a more stable fiber cement product than other companies incorporating more wood fiber content. NichiHa also recycles 95% of the water used at its manufacturing facility and treats the remaining 5% that is discharged. Overall, I was very impressed with NichiHa's strong environmental conviction. The siding was pre-painted with 2 coats of a low VOC paint and it comes with a 25 year warranty. This not only saved money, but also the time and headaches associated with painting the material on site. The shakes were also pre-stained with 2 coats of a low VOC stain. Having the shakes pre-stained was very important to me as all 6 sides would be fully covered. Many builders only paint or stain the exterior side or face of the shakes which usually results in a lower quality product that is more susceptible to the elements over the years. I also chose a darker stain for the shakes as this will reduce UV damage and require less restaining in the future. The tongue and groove pine used on the soffits and the ceiling of the front porch is called Blue Stain. The blue stain results from a fungus that is released from the mouths of beetles that infest the pine trees out west ultimately killing the tree in the process. I used this blue stain pine for both environmental and aesthetic reasons. The dead standing trees can be used for certain applications and the stained byproduct matched my overall color scheme.
In my spare time I have also been working on a smaller prototype cottage design that starts with a basic 28x36 footprint. This cottage plan will have 5 different floor plans or layouts ranging in size from 1008 sq ft to about 1500 sq ft depending on the specific needs of the client. For these cottage plans, I would use Eco-Panels walls with the integrated LP Smartside siding option and Carolina Colortones to finish out the gables and trim details. Having the siding already integrated as part of the structural and insulated wall system significantly reduces costs, delays, waste and headaches. Finished as a board and batten style, these cottage plans will also be very high performance, while potentially being even more affordable than this larger prototype.

1st Energy Bill

Today, I received my 1st utility bill and my Energy Star documents for this prototype home. My HERS score for this prototype is 54. The HERS index is based on using a code based home for energy modeling purposes that starts at a score of 100. In order to achieve the Energy Star Certification, a newly built home needs to score an 85 or lower (better), which means that the new home, with a score of 85, is supposed to be 15% more energy efficient than the code based model home at 100. So in these basic terms, since my score is a 54, the math says that my prototype should be at least 46% more energy efficient. Because this index is making some very general assumptions, the HERS score/index is and should only be used as a basic comparison. The reason I say this is because of what my 1st utility bill actually is. As I've mentioned in previous posts, both the Energy Star rater and myself expect this home to exceed 60% in energy savings compared to an average non-certified code based home. Based on the REM software that Energy Star uses to calculate the HERS score/index, this prototype (all electric) is expected to use (based on current local kw/hr rates) $1133.00 per year in total utility costs. Divide this # by 12 months and I should average about $94 per month on my utiltiy bill. Although I recognize that a single monthly bill is not a really accurate comparison, it's a good place to start. My utility bill for the 1st month is $49.89. We can then assume that if the software was completely accurate and the 1st bill was for $94, then the code based model homes utility bill would be about $175. With a real utility bill of $49.89 and using the assumptions of the Energy Star software's code based model, this means that this prototype's 1st utility bill is 71% less than what a code based model home's utility bill might be for the 1st month. This is a very positive sign that this prototype is going to perform exceptionally well considering what the total cost was to build this home. I will be turning the ERV down to the low setting as it is recommended to run the ERV on high for at least the 1st month. I will also be turning the dehumidifier off intermittingly in the crawl space and monitor the moisture levels now that the crawlspace humidity level is stable. Changing the ERV to low and reducing the amount of time the dehumidifier is running should both reduce the electrical load. It will be interesting to see how this affects the next utility bill.

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.

The Test Results

My last post talked briefly about the cost per square foot and I will revisit that subject in future posts. I would like to discuss the performance #'s that were verified by Amy Musser (www.vandemusser.com). Amy, who I consider the leading building scientist in this region, and her technician Jeff came out to the job site to perform the Energy Star and NC Healthy Built Homes Certifications. Because all of the duct work is located within the thermal boundary of the building envelope the most important test was the blower door test. This test depressurizes the house to measure the leakage of air in the conditioned space to the outside. A large fan is attached to a blower door bracket as you can see in the picture. One of the prerequisits for the NC Healthy Built Homes program is to achieve 3.5 air changes per hour (ACH 50-pascals) or less of leakage. This means that the volume of air within the conditioned space of the house exchanges with the outside air 3.5 time or less per hour with all the windows and door closed. Although I don't specifically know the best blower test results I encountered when I was doing the certifications, typically anything less than 1.5 ach was really good. After Jeff set up the blower door, he started the fan and was not able to get a reading. It took all 3 of us to finally get a reading. Jeff was running the fan, Amy was checking the diagnostic equipment and I was holding the bracket in the door opening with all my strength so it wouldn't pop out-which it did twice. After a few attempts, we were finally able to get a reading and I'm glad we did because I wasn't sure I could hold the bracket in place any longer. As a former H.E.R.S rater, I knew that this was a very good sign that the house was really tight. It wasn't until later that evening that I got the results from Amy. The previous best results that any of us knew about for any home was 220 cfm of leakage. This test came from another home built in the Asheville area (also using Eco-Panels) and is about 1440 square ft. This other home is 430 sq ft smaller than my prototype and has about 4500 less cubic feet of volume. My prototype only had 181 cfm of leakage and a final ach reading of .48 ach50. It felt great to have such an impressive score and be the new record holder. Another way (in my opinion a better way) to measure leakage of the envelope is ELR (envelope leakage ratio). My ELR is .039. I talked to the director of the Earth Craft House Certification program at the Southface Institute in Atlanta about my scores. Although he was very impressed with the test results, he admittedly couldn't believe it. ELR standards for the Earth Craft House program is around .4. Obviously my prototype at .039 is 10x better than that standard. I will continue to research and find out how this score compares to other top blower door test results throughout the country. Although having a super tight house is a great achievement, please remember that proper ventilations is as important. I am currently running my ERV on high (as it is advised to do this for the 1st month), but this week I will reset the ERV to the low setting after cleaning the filter. I attribute the superior blower door test results to two factors. 1) Using Eco-Panels and 2) Paying close attention to proper air sealing anywhere and everywhere I could think of. It was a few days later that I received some more good news. My prototype home achieved Gold Level for the NC Healthy Built Homes Certification. Over the next year, providing everything works out properly, between the landscaping points and PV solar panel points, this protoype with achieve the highest level of Platinum.

Prototype Home Completed--Well Almost!

After many requests to update this blog, I have finally taken the time to do it. Between the months of July, August and September, I was putting in 16 hour days on a regular basis trying to hold down my full time job with Eco-Panels while also completing this prototype. I appreciate your patience as sleep became more of a priority. Althought the # of listed followers is small, over the last 6 weeks, I've had dozens of people ask me why I haven't updated the blog. I will do my best to catch everyone up to date on the protoype and the impressive test results it acheived. There are still many areas of the project that need to be completed like the landscaping/fruit and vegetable gardens and the driveway/carport/workshop to name a few.
While I am still working through the final costs associated with this prototype, I can estimate that the total cost per square foot is around $105. Although I didn't reach my goal of $100 or less per square foot, the combination of cost, quality and performance is the best I've seen anywhere in this region. Building on a crawl space as opposed to the original slab on grade, is partly to blame for the additional costs. Also, it was very difficult for me to stay on top of every detail during construction and instruct the contractors as to how important it was to reduce waste and pay attention to being extremely efficient with time and materials. Although a 60 day build time was aggressive, I feel confident that with the right team and proper planning less than 90 days from start to finish is easily achievable. Since this is a prototype, some learning curve is expected, but I also highly recommend working with suppliers and contractors that are committed (personal conviction) to always taking the extra time to stop, think, ask, measure and or read the instructions. Because of my background as a H.E.R.S rater, Healthy Built Home Certifier, working for custom and production builders and working for Eco-Panels, I was able to get all the really important aspects done correctly.