We’re a couple of city folks who moved to the country with dreams of pursuing a more sustainable lifestyle. This site documents the building of our net positive house (we hope to generate a bit more power than we consume each year). We were net positive for 2012, our first year in the house.
General Specs and Team
Location: Cambridge, NY
Bedrooms: 2
Bathrooms: 1
Living Space : 1200 sqf interior space / 1408 sqf enclosed space
Estimated Cost (USD/sq. ft.): $142/sqf (estimated* = projected budget / enclosed space) *Not including significant site work.
Actual Cost (USD/sq. ft.): $208/sqf (actual* = what we spent / enclosed space) *Not including significant site work or mortgage related expenses.
View the construction documents (1.7 Mb PDF). Updated 6 March 2011.
Completion Date: May 2011 November 2011 December 2011
Designers: Larry and Jill Burks (homeowners)
Builder/Contractor: Warren R. Coolidge
Energy consultants: DEAP Energy Group (Mike Duclos, Paul Eldrenkamp, Paul Panish)
Construction
Foundation: walkout basement
Under-slab insulation: R-30 (3 layers of 2″ XPS)
Foundation wall insulation: R-41 (2″ EPS + 9″ dense pack cellulose)
Walls: R-44 (12″ of dense pack cellulose)
Roof: R-75 (24″ of loose blown cellulose)
Windows: Accurate Dorwin triple-glazed fiberglass windows (Casements U-0.24/SHGC 0.47 south, U-0.20/SHGC 0.44 north, east & west) (Fixed U-0.22/SHGC 0.55 south)
Doors: ThermaTru fiberglass doors U-0.24
Air tightness: Shell test: 159 CFM (0.56 ACH) Final: 131 CFM (0.46 ACH or 0.03275 ELR) (see post, Shell blower door test results.)
Energy
Space heating: Mini-split Air source heat pump (Mitsubishi MSZ/MUZ-FE18NA), electric resistance backup
Domestic hot water: 50 gallon Marathon electric water heater
Air conditioning: Open the windows or Mini-split ASHP
Energy Star appliances and LED/CFL lighting.
Solar PV: 30 – 230-watt Solar photovoltaic modules, totaling 6900 watts of peak DC power. Fronius IG Plus 7.5-1 UNI Inverter. This system will provide approximately 682 kWh per month on average. (We produced 719 kWh on average per month for the first year.) See solar related posts.
HERS Index: 22 (see post, It’s official, we earned our 5+ Energy Star rating. But the result was not what we expected.)
Energy Star Score: 5+
Est. Space Heat Demand: 12,416 kBTU/yr.
Est. Total Source Energy: 55,231 kBTU/yr.
Est. Total Site Energy: 20,456 kBTU/yr. (5,995 kWh/yr.), Actual for 2012: 5,601 kWh.
Est. Hot Water Energy: 8,326 kBTU/yr. (2,440 kWh/yr.), Actual for 2012: 1,528 kWh.
Indoor Air Quality
Mechanical ventilation: UltimateAir RecoupAerator ERV
Green Materials and Resource Efficiency
- Trees removed from site were milled for future barn framing, house stairs and trim. The remaining hardwoods were bartered as firewood.
- Zero VOC paints (interior)
- 1000 gallon rain water storage tank
- Low-flow plumbing fixtures
- Energy efficient appliances
- LED & CFL lighting
- Locally harvested and milled Brown Maple interior floors
Hi Larry and Jill, I just discovered your blog when I was looking to see who had signed up for this year’s solar tour. The blog and your house are very impressive and neat. I am writing to introduce our new energy independence commuinity (opening late September), and to see if you might be interested in participating. You can learn a little about me and the house I’m building on my website. Let me know what you think. Cheers, Dan
Hi Dan, thanks for your comments. I think we met last year. We visited your house as part of the NESEA Green House Tour, which we’re participating in this year in addition to the Solar Tour. I’ll email you to find out more about the energy independence community. Thanks again.
Oh, it is a smaller world than I thought. It is funny how our houses look the same. Unfortunately I have not been able to make as much progress as I had hoped. We have added the garage and PV (soon to connect to the grid) and a root cellar but little else this last year, so from the outside it still looks about the same. Yes please email me and I can send some details on the comming community. Cheers, Dan
Larry and Jill, very impressive site. I began my own blog due to the absence of actual details for super insulated construction. One can find websites that discuss super insulation and passivHaus concepts, but few sites that are willing to share their plans or details and even fewer sites willing to share their actual building experiences. I feel your site will become one of the true landmark sites. Thank you. Richard
Thank you very much Richard. We spent some time pouring over your blog (nbsuperinsulatedhouse.blogspot.com) when were still in the early phase of construction. We enjoy documenting our thoughts and progress, and hope it helps more people contemplating building a new house to invest in a super insulated tight envelope. Thanks for reading!
Larry & Jill
Larry, It’s really hard to believe the little patch of Texas that we came from and that we share the same vision still. The house is amazing and that you are opening up your secret sauce to share with the rest of the world is exactly what I would have expected of you. I do hope that more and more people take this approach to their dwelling and adopt the notion that our abodes are merely tiny specks on the bigger home called Earth. Congrats and I am proud of you, amigo… Luis
Thank you Luis, very much appreciated. Congrats to you and Kate on your amazing rehab and good luck on your next abode. Let us know if you need any secret sauce…
Larry & Luis,
Great to see that you are both pursuing sustainability focused projects in your own lives…It is fascinating to me that we all have ended up with similar ideals as they relate to the built environment…You can get a sense of my sustainable real estate focus from my website and the blogs of my students and our study tours…
All the best,
Fred F.
Hi Guys,
My girlfriend just found your blog and we’ve been researching almost identically what you have accomplished. The blog has been great. We are currently looking for property in that stretch of NY between Albany and Lake George. I spent many weekends of my childhood in the Catskills.
If I may ask, what do you do for income? Do you have adequate savings you lean on until the farm is up and running (if you plan to make it a profitable venture)? It’s all like a puzzle to us and we’re trying to find and make pieces fit.
Any info would be helpful.
Thanks!
Eric
Hi Eric,
That’s a great area to search, especially up near Lake George.
In answer to your question, we both have full time jobs. I work from home and Jill has a publishing job about a half hour away.
Farming is a hobby and educational experience for us, but we’re always scheming ways to transition at least part time to farming.
You’re welcome to stop by for a visit. Good luck on your puzzle pieces.
Hi Larry,
We would love to swing by for a visit. We may be in your very neck of the woods this coming weekend (3/16-3/17) if you are around. Sorry ’bout the short notice.
Could you email me your contact info?
Thanks!