Construction is fully underway at a new passive solar home I am building and we are using the next generation of thermal mass windows. An incredible achievement in passive solar technology, capturing and storing the suns energy in your windows.
Since last posting here I have joined forces with Next Step Living inc. a Boston MA based company that is leading the way in energy efficiency and having a substantial impact on improving our existing housing stock. A very challenging and rewarding job to say the least.
We have begun building a passive solar home located in central MA in the town of N. Brookfield. To follow this new project here is the link to the new blog.
http://www.nextsteplivingnewhome.blogspot.com/
Tom Pittsley
ecobuilder@aol.com
tom.pittsley@nextsteplivinginc.com
www.eebt.org
Saturday, October 16, 2010
Monday, June 14, 2010
Heating a home in Massachusetts for $341 a year
If you have been following this blog, it has been a long time since my last post. In May of this year the homeowner of the house (highlighted in my previous posts) has been in the house for one full year. I collected all of the energy bills for the last year and sat down and did the calculations. It was pretty simple to figure, as the house has only electricity for it's energy supply. Well let's not forget the solar energy that is used to heat this home. No, no solar panels on the roof, no solar hot water, and no PV, just plain old passive solar energy, combine with an air tight, highly insulated envelope. We also cannot forget the windows. Take a look at one video that shows the windows reaching 112 degrees on a 34 degree winter's day.
So after sitting down and calculating the energy costs for the home, it was pretty clear to see how well passive design and the right windows can reduce your heating costs. To calculate the heating costs for the winter months we calculated the monthly base load used throughout the year and then deducted this from the actual usage to come up with $341 for heating this 2,000 sq/ft home for the entire year. One factor that cannot be calculated into costs and that is comfort. Comfort is the thing the homeowner talks about whenever I see her. She can't believe how comfortable her new home is, warm windows on a cold winters night, unheard of here in New England. The windows never actually go below room temperature even on the coldest nights.
I am about to begin my next project and this one is going to be even better than the last.
New Thermal Mass windows are finally ready for a test run in a real home and the lucky recipients, the Melad family of N Brookfield MA are getting the latest development.
The new windows were finally made public this last week, with the debut at the 2010 AIA national convention in Miami, finally my silence can be broken. I have been working with the inventor for the past few years but always stifled by a non-disclosure agreement and have been anticipating this for more than a year now. These new windows are the most advanced window product you can find, they capture, store, absorb and reflect solar energy. How can they do all that? The glazing system used for the windows has a unique combination of glass, low-e surfaces, gel to create a window with an R-5 (U-.2) insulation value and a SHGC-.72 along with mass capable of storing thousands of BTU's on a sunny winter day. This window has 4 panes of glass, the two inner layers have a clear gel encapsulated with the space between. This clear gel acts as a thermal mass and stores the suns energy, much like the water did in the previous version. The thing that really puts the icing on the cake are the shades. The newest version has motorized shade system that retracts up into the head of the window and hides itself away when the house gets to warm. They can be controlled by a simple thermostat placed near the windows and be set to close at your desired temperature. Pretty cool, huh!!! With the shade down the SHGC drops to .144 twice the reduction needed to reach the energy star rating for low SHGC. I am awaiting the latest press release with all the details about the product. Here's the tough part, you can't get them yet. They still haven't put them into production and are not available to the general public yet, but after their debut at the AIA conference it is just a matter time. Stay tuned!!!
Tom Pittsley
ecobuilder@aol.com
www.eebt.org
So after sitting down and calculating the energy costs for the home, it was pretty clear to see how well passive design and the right windows can reduce your heating costs. To calculate the heating costs for the winter months we calculated the monthly base load used throughout the year and then deducted this from the actual usage to come up with $341 for heating this 2,000 sq/ft home for the entire year. One factor that cannot be calculated into costs and that is comfort. Comfort is the thing the homeowner talks about whenever I see her. She can't believe how comfortable her new home is, warm windows on a cold winters night, unheard of here in New England. The windows never actually go below room temperature even on the coldest nights.
I am about to begin my next project and this one is going to be even better than the last.
New Thermal Mass windows are finally ready for a test run in a real home and the lucky recipients, the Melad family of N Brookfield MA are getting the latest development.
The new windows were finally made public this last week, with the debut at the 2010 AIA national convention in Miami, finally my silence can be broken. I have been working with the inventor for the past few years but always stifled by a non-disclosure agreement and have been anticipating this for more than a year now. These new windows are the most advanced window product you can find, they capture, store, absorb and reflect solar energy. How can they do all that? The glazing system used for the windows has a unique combination of glass, low-e surfaces, gel to create a window with an R-5 (U-.2) insulation value and a SHGC-.72 along with mass capable of storing thousands of BTU's on a sunny winter day. This window has 4 panes of glass, the two inner layers have a clear gel encapsulated with the space between. This clear gel acts as a thermal mass and stores the suns energy, much like the water did in the previous version. The thing that really puts the icing on the cake are the shades. The newest version has motorized shade system that retracts up into the head of the window and hides itself away when the house gets to warm. They can be controlled by a simple thermostat placed near the windows and be set to close at your desired temperature. Pretty cool, huh!!! With the shade down the SHGC drops to .144 twice the reduction needed to reach the energy star rating for low SHGC. I am awaiting the latest press release with all the details about the product. Here's the tough part, you can't get them yet. They still haven't put them into production and are not available to the general public yet, but after their debut at the AIA conference it is just a matter time. Stay tuned!!!
Tom Pittsley
ecobuilder@aol.com
www.eebt.org
Saturday, November 14, 2009
Passive solar home construction: Walking the walk
I have been talking the talk for a long time, but walking it is a different story.
Building a passive solar home and designing one are two different things, measuring it's performance is another. While over the years I have built several homes that were designed for passive solar all to some varying degree. In 2008 I had the chance to design and build a passive solar home for Linda Johnson and her two children, Rachel and Max. After over twenty years of construction, the last ten having been dedicated to building better buildings, I finally had my chance to use my years of knowledge as a Design/Builder to create the most energy efficient home I have ever built. It was great to work with a home owner to design the home of her dreams, while I focused on ways to reduce the energy demands and cost of the homes construction. Below is a list of the house specifications, along with the total energy usage to date.
Location: Middleboro MA
Size: 1,976 sq/ft = 183.5/sqm
style: Modified single level ranch style
3 bedroom, 2 bath, kitchen/dining/living, laundry, utility, and entertainment/wetbar
Oriented to capture as much passive solar as possible 180 degrees south along long side 68'
Roof slope maximized for active solar to be added in the future, conduit in place
Cost of construction $269,000 plus extras and appliances total cost of $290,000
$135 sq/ft base costs $145 sq/ft final cost
10% ratio of floor to south facing glazing,196 sq/ft, 46 sq/ft conventional,
150 sq/ft of specialized thermal mass windows: More info on these windows
Completely insulated slab-on-grade foundation w/integrated radiant heating/cooling R-15
6-1/2" Structural Insulated Panels for all exterior walls R-24
10-1/4" Structural insulated panels for the ceiling 1,300 sq/ft R-40, conventional frame above
7" of closed cell spray foam in cathedral roof section between conventional rafters,940sq/ft R-40
Additional insulation at sill points to address thermal bridging
Air sealing,using negative pressure during construction to find and seal all air leaks
Heat Recovery Ventilation system w/programmable control
Ground source heat pump to provide heating and cooling to the radiant slab
Energy efficient appliances
Whole house De-humidification system
All energy supplied to the house as Electricity
Date loggers to record efficiency of systems and monitor comfort levels for Temp/Humidity
The standard for total annual energy use under the Passive house Institute standards is < 120 KWh/Sqm. To meet the standard this house would have to use less than 22,000 Kwh's annually: 183.5X120=22,020.
While the house is about to undergo it's first New England winter while occupied, the performance to date has been consistent with the energy model. The house has been occupied for 6-1/2 months now and the total energy used to date is 6,020 Kwh's. If it continues through the winter meeting the expectations the total annual energy consumption will be around 12-14,000 Kwhrs surpassing the standards set by the passive institute by 33% or more. While I didn't do a blower door test to measure the air leakage rate or have a way to separate heating energy from total energy, the final Kwh's of energy consumed will be the measure. No complicated measure devises and costs, just the electric meter the electric company provides. We have been logging the energy use by simply reading the meter at different intervals and recording the actual energy consumed. On April 20th 2010 the house will have gone through one full year of occupation, on that date I will be able to confirm if it has met or exceeded the standard.
It's going to be a long winter's wait !
Tom Pittsley
ecobuilder@aol.com
www.eebt.org
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