NZE: The inside story

NET ZERO ENERGY (NZE) is not a claim, it is a process for designing, building, and testing to assure the promise of NZE is achieved. That requires imagination, experience, attention to details, and third party testing to assure the NZE standards are met.

For those interested in the technical ins and outs of NZE, here is a small crash course.

FAQs

Smart buyers have questions

ZER is the answer

How Do You Measure Energy Success?

There is a standardized energy rating system that is accepted by national building codes. It’s included into our 2018 Residential Building Code. It’s called HERS: “Home Energy Rating System”. The lower the HERS Index score the better.

Our NZE HOMES are 10 tp 25 years ahead of the building and energy code requirements. Learn more about HERS Index ratings here.

HERS index analyzes the building envelope for insulation value, infiltration, window and door efficiency, HVAC efficiency, and alternative energy sources like Solar and Geothermal.

  • HERS 130 to 150: Existing older homes

  • HERS 100 to 130: A standard US newer home built on or before 2006.

  • HERS 65 to 100: A well insulated home 2006 to 2018

  • HERS 60 TO 65: A new “energy efficient” home built (code-compliant new homes on the market today) has a HERS score of about 60-65 (the blue arrow). Actual HERS certification is not currently required, only a pass-fail energy inspection, no quality assurance oversight, and no inspection by a HERS-rated inspector.

  • HERS 30-35: “High Performance Energy Homes” (example, Toll Brothers “High Performance Energy Option”, California only.)

  • HERS 0 - 3: Our Net Zero Energy homes have a perfect gold-standard HERS Rating score of ZERO, true Net Zero Energy homes meeting the highest standards of quality assurance, inspection, and certification

Third Party Testing

One of the great things about the HERS system is that it includes third party testing by accredited by HERS as Energy Raters

“Blower Door Testing”: Air infiltration through cracks and crevices or missing sealing is one of the biggest energy losses of a home. To make sure this is eliminated, air is suctioned out of the house with a powerful blower and the integrity of the home’s seal is verified. If the house has air leaks, the Energy Rater will find them using a hand held fogger to see air moving at any open cracks. These areas are then corrected, assuring that the house is “super-sealed”. The testing equipment must achieve two times the air seal of the comparable code-built new home.

“Duct Blasting”. All of the ductwork is visually checked for seal. It is then pressure tested to assure it doesn’t leak conditioned air.

HERS Index explained. Click to enlarge

Click to enlarge. Certified energy analysis.

Blower Door Testing

 

What is Super-Seal and Super-Insulation.

The insulation values are between 50% to 900% better than current new home standards. But just increasing insulation is not enough if walls, ceilings and floors leak outside air.

  • WALLS New homes at R=19     Our NZE home R=31  162% + better seal →

  • ROOF New homes at R=49    Our NZE home R=75   167% better

  • BASEMENT WALLS New homes at R=15   Our NZE home R=21 140% better 

  • DUCT INSULATION AT ATTIC New Homes R=8.   Our NZE home R=75, within building envelope, 900% better

  • BASEMENT FLOOR New homes R=1 concrete only, no insulation requirement . Our NZE home: R=7, 700% better

  • AIR INFILTRATION:  New homes 3 ACH (air changes per hour in volume).  Our NZE home: 1.5 ACH  100% better

  • SUPER-SEALING. Using a variety of construction techniques to double layer the walls and ceilings plus blower-door and duct-blast testing (above).

Full time filtered fresh air makes an NZE home “healthier”

NZE is “Super Sealed”, so the air inside the home would become stuffy and stale. Before NZE, all homes, new and old, solve this by plain old “leaking” of air from outside. In NZE, an “ERV” Energy Recovery Ventilator exhausts stale air and fresh air is brought in. To conserve energy, heat or cooling in the exhaust is transferred to the fresh air coming in. The ERV filters particles as small as 1-10 microns, which includes most bacteria and allergens. This fresh air is ducted throughout the house.

 

Is a Net Zero Energy (NZE) home complicated to live in?

An NZE home is SIMPLER to live in! Its HVAC system has fewer moving parts and lasts longer than a standard HVAC system It has no special controls or maintenance. It is just better! Smart controls make life easier. Filtered fresh air makes the interior air cleaner.

Is Net Zero Energy new and untested?

Does Net Zero Energy cost more than a standard new home?

The upgrades ton NZE gold-standard are an initial additional cost, yes. But unlike other upgrades, our energy upgrades pay the homeowner back.

  • Our “High Performance Energy” option actually costs $100 LESS per month and yields a $17,325 tax credit.

  • Our NET ZERO ENERGY OPTION costs less than the average Verizon or Comcast bill and adds over a $75,000 tax credit.

Will my mortgage lender understand all of this?

  • Green Energy lenders will qualify buyers for higher purchase prices because they recognize the savings of a net zero energy bill.

  • Green energy-trained appraisers will appraise the home at a higher value than the standard comp. An NZE home will appraise for as much as 10-15% higher than a comparable code-built home.

  • Lenders and appraisers who are up to date on the latest government-approved practices will be happy to help. Our green energy consultants are ready to bring them up to speed.

Do other builders offer NZE?

Some builders are introducing higher-performance energy homes. Toll Brothers, one of the US’s largest builders admits that its average new home has a HERS Index rating of 59, a middle-of-the-road score. In California, they are offering a energy-premium option with a HERS rating of 25, much better. It’s not NET ZERO, but a worthy effort)

Why are these the only NZE single-family homes in the Delaware Valley?

  • An NZE home costs more to build. Most builders are not willing to risk sales based on bottom dollar comparisons

  • An NZE home is has rigorous design and inspection standards. 3rd party energy consultants, inspections, and additional architectural design are all unfamiliar territory to production home builders.

  • Our NZE homes are a vision project. We believe we can make a difference and there are smart buyers who want that for their homes as well. We are willing to go the extra mile to make a difference.

  • Builders are very cautious. They want to repeat a proven formula: build, profit, and repeat. Innovation is not in their DNA.

Why don’t building codes require NZE?

They will !

Five years ago, in June of 2018, the U.S. Conference of Mayors unanimously adopted a resolution to urge mayors to adopt the IECC as a strategy toward net zero building construction by 2050. Two and a half decades away

The International Code Council (ICC) writes our PA, NJ, and Del building codes. They already require a HERS Index Rating of about 55 for new homes. They are planning on introducing better HERS Index ratings requirements by their 2030 and beyond codes. PA currently uses the 2018 Residential Code. The ICC plans on making energy requirements better and better, with a path TO NET ZERO standards (not requirements) 10 to 15 years away. By then, our NZE buyers will be over $450,000 in future value ahead of the crowd. ($15400 / year @ 20 yrs @ 7% + 1% inflation)

The US Department of Energy already has a Zero Energy Read program. Design Build LLC is a US DOE ZERO ENERGY READY partner.

How much does a Net Zero home help the environment

One measure of environmental impact is “Carbon Footprint”: the amount of CO2 that the use causes to be released into the air.

 The Carbon Footprint per of these items uses per year.

  • Our Net Zero Energy home is Zero Carbon Impact

  • Existing older house of 3500 SF has a carbon footprint of 10-12 metric tons of CO2 per year

  • Average newer home has a carbon footprint of 7-8 metric tons of CO2 per year

  • Newer car driving 15k miles per year has a carbon footprint 3.8 metric tons of CO2 per year

  • An electric car, 15k Miles per year has a carbon footprint 1.5 - 2 metric tons of CO2 per year


Living in the comfort and quality of a Net Zero Energy, Net Zero Impact home makes a homeowner part of a better energy future, for themselves, the community and their world.

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