Tuesday morning National Grid showed up to turn our power on, what a great day. After the last few weeks listening to the generator running it was nice to have have peace and quite. Well not exactly quite, with the compressor, saws and nail guns all day long but still much better than listening to the generator.
Some of the other things that happened this week.
I picked up the first 4 of our solar windows, man are they heavy. These windows have 4 layers of glass, with a 1" thick layer of clear gel encapsulated between 2 of them. Each of these 2'x6' windows weighs about 250 pounds, it's a good thing I have a one ton truck. These windows capture and store the suns energy within the gel layer and then radiates it into the house at night. They also have an exterior solar shade that retracts up into the head of the window that shuts the suns energy off when it's not needed. If you have the chance come by and see them for your self at the tour next weekend.
We finished the last couple of wall panels on Monday and the rest of the week prepping for and installing the roof panels. Installed our triple 16" x 48' LVL ridge beam and got more than half the roof panels installed. only one week left until the Green building open house tour, next weekend and still a lot of work to do.
What are SIP's and what do they do? Structural insulated panels, are a wall system that has been used for decades but has the misconception of costing more. If you take the cost of the materials alone, then yes they cost more if you add in the savings for labor and waste then the cost is about even. The panels themselves are comprised of expanded polystyrene insulation with two skins of Norboard laminated to them. Making an incredibly Strong and straight panel system that can be interlocked to create a highly insulated and air tight shell of the house. Let's take a typical stick frame wall system that is used to build virtually every home in this region. (New England) 2" x 6" wall framing with R-19 fiberglass batt insulation. When you factor in the thermal bridging of the wood framing the total R-value of the wall system is reduced to about R-13.7 ( ORNL whole wall calculator) SIP's give you an total wall R-value of about 22.25 nearly double that of a typical home. The other really big factor is the air tightness of the SIP's envelope, something that is essential when constructing a passive solar home.
The process of prefabricating the panels reduces the time spent building the home and reduces labor costs by about 30% if designed properly. Notice I say if designed properly, I cannot stress enough how important proper design is essential to getting it right and reducing costs. One guy I know said he built a home with SIP's and hated it. i asked why and he said that cutting in the windows and doors was a very messy and time consuming process. I couldn't believe it, I had never heard on anyone fabricating the panels in the field. I wouldn't even consider doing this. While sometimes changes need to be made in the field, which is fairly simple, the thought of cutting out all the windows and doors would be daunting if done in the field. The panels we are using come from Branch River Plastics, a company located in N. Smithfield RI less than 50 miles from the job site and are totally fabricated to exacting dimensions. This makes installing the panels a breeze and virtually eliminates waste in the job site. No dumpster needed
This is one of my personal goals when building a home. No dumpster! Yes we have some waste but with careful attention to detail this can be dramatically reduced and materials can be chosen that are easily recyclable. On our current project we will not be using a dumpster reducing operating costs even further.
When you combine the reduction in labor and waste, add the increase in insulation value and air tightness, SIP's are one of the best methods to build better homes. While this is just my opinion, it was formed through years of personal experience and research. I spent 18 years building with the old method and the last 10 using alternative materials and have found no other product that can increase your home efficiency without adding significantly to the costs of building better than SIP's.
We are also using the SIP's for the roof of the house increasing the homes efficiency by another 30% of traditional methods. When all of the factors are combined you end up with a home that uses about 40-50% less energy to heat and cool than a traditionally built home. My last project built in Middleboro MA using a SIP's envelope along with passive solar design, efficient heating and cooling, that house heated last winter for only $341, my goal is to make this one even better. We will continue to track this homes performance long after the project is completed, to ensuring that we are reaching our goal of building the most efficient homes possible.
Some of the small things that have a big impact on energy savings
It all starts with the foundation
There are tons of details that go into to making a home and it all starts with the foundation. Have you ever though about your foundation and how little insulation is has? Even new homes, built recently fall short in this area. Current building code requires that all foundations be insulated, the common practices used leaves something to be desired. Most homes built today have insulation on the exterior of the foundation but for some reason builders stop the insulation at grade. This creates a large area of your home that is subjected to the elements with almost no protection. Did you know that the concrete of your foundation only has an insulation value of about R-1? That's less than a window. One of the things we do is to insulate all the way up to the sill of the house. This results in your foundation being fully protected to an insulation value 12 times greater than traditional methods. Along with this we also insulate under the concrete floor of the basement and up the sides of the basement slab. These things combined have not only a big impact on your homes energy usage but also contributes greatly to the comfort within the home.
I do know why traditional builds don't do this, it's simple. Costs! It isn't a huge cost but most builders are not willing to spend the extra time, money and effort to do this, but this is just one of the things that differentiate us from most builders. As a company we understand the implications that not doing this will have on your home and the costs to you the homeowner, having to heat and cool this home.
So, here I am at 3pm on a Friday afternoon waiting for concrete to arrive. It's going to be a late night. It's pretty typical, concrete work requires a lot of preparation for a few short hours of work. After the foundation guys finish pouring the walls I need to install the tie downs and anchor bolts specified by the engineer. Hopefully I can finish up by 6pm for the long ride home. Next week I will be bringing up my camper as the actual building starts, no more 3-1/2 hour commute a day. They will be coming up to strip the foundation on Saturday and Monday we will be waterproofing and insulating the foundation. The excavator will be installing the perimeter drain and back filling as we go. If all goes as planned we will be building the floor on Tuesday, right on schedule.
The concrete finally showed up at 4:15 and the foundation is complete!! 6pm
What could be so special about a window, that I can't hold back my excitement? These are no ordinary windows. You could call it a solar heating and cooling system along with a view. It really and truly is a system, not just a window. The window has the capacity to capture and store the thermal energy created by the sun on even the coldest days of winter. I have seen it work on our previous project, for more information on that project go to http://tompittsley.blogspot.com/ where I have many posts and videos of that project and window system.
Ethan & Elisabeth Melad
Dan Fogarty, Solar window project engineer
These windows are even better than the last, they now have an integrated external shade the retracts into the head of the window, that can almost completely shut off the suns energy while still providing lite and a view. They can be completely controlled by a digital thermostat and/or remote control. The thermal mass is now a gel and does not have the problems the water window had and the cost will be less. We still have no idea of how much these will cost once, Hunter-Douglas puts them into production we will know. Our windows are a prototype and only the 3rd installation in the country, three are in a home at the solar village in Colorado and few more in a low income housing in here in MA.( I'm not sure where Sudbury/Weston maybe?) This home will feature 21 of these windows along the South side and should be able to provide 65-75% of the total heating needed for this house. It will definitely be the first of it's kind, with hopefully more to come.
So I thought it would be important to describe what makes this home so special and give an overview of the things used to create an efficient home. To build a solar home it takes a lot of careful planning that starts long before the construction starts. The design phase of a solar home project is critical in making it all work. It starts with a solar site survey that will determine the amount of solar energy available at a given site. This is done with a tool called the solar pathfinder which can define the actual amount of energy available, it accounts for shading at the site and uses 30 years of weather data to calculate the total energy available for given date, month or year. It can then create a report for solar electrical power, thermal power for solar hot water (SHW) and solar energy striking the south windows. It gets a little complicated after that but this is used to determine the size of the solar systems that can be used and how much you should expect to gain from that energy. For this home we are using the solar energy to heat the home during the winter, create hot water , and aide in cooling the home with the use of a solar chimney.
Another of the important elements of this home is the efficiency of the building envelope. For solar energy to create the energy needed for the home, the home has to use less energy than a normal home. We are doing this with the use of Structural Insulated Panels as the shell of the home. These panels have an insulation value 30-40% better than code built homes ands creates an air tight envelope, that reduces air infiltration below what you can do with traditional construction. They are also pre-fabricated to speed the construction and reduce the waste on the job, they come in large sections 4' wide and up to 24' long.
Many of the traditional passive solar design principles, that have been used for centuries are used but in a totally unique way. Large southern expose, proper orientation, thermal mass and shading are all things that need to be considered. Here is where this house differs from tradition and what makes this home so unique.
Passive solar Window system Breaking the Mold
Windows have long been the nemesis of passive solar design. To get a window that allows a lot of solar energy to enter the home you had to sacrifice the insulation value of the window. This made them a leak in the envelope when the sun wasn't shining. Our windows allow for 72% of the solar energy to enter them and insulates them 50% better than energy star rated windows. SHGC.72 Uvalue.2 This is done with a unique combination of LowE surfaces and a particular type of glass. That sounds great but how to you shut off the energy when it is not needed? Traditional design has been to create overhangs that shade the sun during the summer months. While this works well, if you don't mind the look of large overhangs, it can never give you total control over the sun. The low sun angles during the morning and afternoon hours will still strike the house and create unwanted heat from entering during the summer and swing months. To fix this this, these windows have an exterior shading system integrated right into them. A retractable exterior shade that hides itself into the head of the window and can be controlled by a thermostat and override switch. Giving the homeowner total control over the energy entering the windows and their home.
That all sounds good right? but how do you then store this energy? Once again here is how these windows differ from tradition. Typically passive solar homes had large amounts of thermal mass (concrete,stone,tile) to capture and store the energy. This works but the downfall is that all of that energy needs to come through the windows warm the space and then strike the floor. This creates a problem with overheating and way to much light coming into the home. Our windows have a clear gel encapsulated between two of the four layers of tinted glass, that captures this energy in the window. The gel is now your thermal mass, no more need for concrete or tile floors and you no longer have to wear your sun glasses in your home. Capturing this energy at the window is also far more efficient than in the floor.
These windows being developed by Wendell Colson, VP of research and development for Hunter Douglas are not yet commercially available but will hopefully begin entering the market sometime next spring. They made there first public debut at the AIA national convention in Miami in April, before that little was known about them. I have been working with Wendell for several years and have had the opportunity to use his previous version of the windows as he has been working out the bugs. One project that was completed in 2009 had one such system and the homes annual heating costs, here in MA were $341 for the entire winters months. Here is a one video showing the previous version of the windows reaching 112 degrees on a cold winters day.
The new windows are far more refined, easier to install, cost less and are expected to out perform this previous version. This home will have 21 of these windows along the south side of the home. While wendell has tested these for over a year now in his test huts, this will be the first large scale deployment in a real home. From his research he has determined that every sq/ft of window you will be able to contribute 100,000 Btu's. Wendell has tested these for over a year now in his test huts, this will be the first large scale deployment in a real home. With 233 sq/ft of these windows is this home and the combination of the efficient envelope, the windows should be able to provide 65-75% of the total energy needed to heat this home. The additional energy will be provided with a wood stove and a very small mini-split duct heat pump. Whats really cool about these windows is that a 11pm on a cold winters night your windows will still be warmer than the room temperature. have you ever felt a window on a cold winters night? The gel that has stored this energy over the course of the day releases this into the house at night, from past experience actually raising the room temperature by a degree or two until 10-11pm before leveling off and maintaining the house through most of the night. The reach there lowest temperatures around 7am the next morning and if the sun comes up, starts the process all over again. As the project continues I will post pictures and videos of the windows going in and how well they perform.
Solar chimney for cooling? Most people have no idea of what a solar chimney is or does. I'll try not to get to technical but it helps to understand a little bit of building science and how heat creates pressure within your home and how that effects your home. The term used in the energy field is the stack effect, what it means in simple terms is that warm air in your home wants to rise and escape from your home, creating high pressure at the highest point of you home. For most homes we want to stop the stack effect, in this home we are using it to help cool the home. The solar chimney is nothing more than a simple framed box on the roof. This box should be designed to heat up as much as possible, dark metal siding works great. The top of the box is built up with enough room for air to escape but not enough to get water in. You then place a well insulated door that can be opened from within the living space into the chimney. When the door is opened The heat creates a natural draft which wants to draw air out of the house. We strategically located windows along the north side of the house, low to the ground that can be opened to allow for air to enter. This natural ventilation will dramatically cool the house under some conditions. The whole house fan system can be turned on to assist in this. If you still need some cooling the mini-split duct heat pump can provide that in a very efficient way.
we are of course using a solar hot water system to provide a portion of the hot water, a Heat recovery ventilation system to ensure indoor air quality while saving the energy. They may even some day put PV panels on the roof, an option they are seriously considering. All energy star rated appliances. The home is hoping to meet Energy Stars highest rating for home efficiency.
The home will be open for tours on Saturday October 2 for 9am-4pm as part of the North East Sustainable Energy Associations green building tour and the national solar tour.
Construction has started on the new passive solar home being built by Next Step Living, for Ethan & Elisabeth Melad. The home, located at 17 Ashley Rd. North Brookfield MA will have many features that make this one of, if not the most efficient home I have ever built. (some of my past projects)
The combination of an efficient building envelope combined with passive solar design and the most innovative solar window that can be found anywhere is what will make this house shine. As the job progresses I will continue to post updates, pictures and videos of the different features that makes this home so special.
A not so quick update of where we are in the project.
We finally got the permit to build the home on August 11th, 2010 and the homeowners finalized the financing on August 13th. The entry way to the property was completed a couple of weeks ago and before that we couldn't even get a truck into the site. The access to the property needed to cross a wetlands area and required 5 large culverts, building up the ground about 5', 14' wide and 100' long, no simple task. The rough driveway, 450' to the house has been completed and the foundation has been dug. The well has been completed along with the excavation of the water line to the house. I spent the last 2 days excavating the 80' of water lines, 400' electrical lines from the transformer, across the wetlands crossing and across the 225' of open field to the house location. Not only has the excavation been completed but this afternoon we completed installing the electrical conduits from the crossing to the foundation hole. 3' deep trench 225' long, with 6" of sand below the conduit, one 2-1/2" electrical conduit and one 1" conduit for the cable lines. 6" of sand on top, some caution tape and the trenches filled back in. The excavation for the foundation was completed today after some help from the large excavator with a hammer drill showed up this morning.( ledge). As I was wrapping up my day about 6:30pm the well guy showed up and installed the water lines from the well head to the foundation hole. On Friday the foundation guys will be showing up to pour the footing for the house and at that time I will be concreting the electrical conduits that run just 6" below the ground along the wetlands crossing, finish filling the well trenches and cleaning up the mess from an incredible week of production.
By the end of next week the foundation should be completed along with insulation, perimeter drain and back filled. After that the fun begins, the following week, with the framing of the house and the Structural Insulated panels will begin to go up. Stay tuned.
