Design, Consulting, Team Leading and Training

ZEPH Concepts

A Certified Passive House™ is the heart and soul of a ZEPH™ structure, which stands for net Zero Energy Passive House.

The Passive House Standard is the most rigorous building energy standard in the world. Consultants, projects or building components that have obtained the right to carry the logo have committed themselves to design excellence and the Passive House energy performance criteria.


Although simple in concept, there is more than one way a building can achieve “zero.”

We use the National Renewable Energy Lab (NREL) definition of net zero for energy costs:

  • The owner’s net energy bill is zero, or negative.
  • Or the building is “off the grid” completely energy independent
The Passive House portion of a ZEPH embodies more energy into the building shell and requires far fewer renewable energy resources to achieve net Zero Energy Building status.

A Passive House provides: Certified-Passive-House
  • Incredible savings on energy
  • Superior indoor air quality
  • Unmatched thermal comfort.
  • Fresh air continually brought into the house
  • Managed moisture and humidity
  • Pollen, dust, and insects significantly reduced though airtight shell and filtered fresh air

See for more information on Passive House

ZEPH: Most cost effective approach to net Zero Energy. And it's Carbon Neutral!

Energy expended in a typical building’s life time of operation is on the order of ten times that of construction energy embodied in the building.

cumulative-energy-use-SMWe believe it makes sense to embody construction energy into conservation efforts which will reap huge dividends in reduced operational energy demand.

This is what the Passive House standard yields. Reduced operational energy equates to reduced total ownership cost.

The building science behind Passive House also provides increased building durability. Moisture control and the increased insulation reduce condensation/vapor drive problems, and the use of ERVs (Energy Recovery Ventilator) for the ventilation system give a consistent humidity relative to the outdoor climate throughout the year. These combine to extend the life of a building built to the Passive House standard. This yields still more value for the additional energy embodied in the construction.

A ZEPH™ takes advantage of an overall lowered energy requirement start point at application of required renewables to achieve net Zero Energy. In other words, a much smaller system is required.

This brings two advantages over a typical ZEB:

1. Reduced cost for the initial renewable energy system (active solar, wind etc.)

2. Reduced cost for replacement of the system when it wears out

Passive House and a Thermos?

New Passive House Construction
Passive-House-Construction-Costs-image2By far the most data available comes from Europe. Best estimates of new Passive House construction lie within the range of 3 to 8% more than that of buildings built to the current standards of the New American Home (TNAH) 2006 or about even with the German EnEV 2009 code. Not bad, but the reality is that Europe already has a robust supply chain of Passive House quality components. When building in North America, the cost is in the range of 10-15% higher than TNAH 2006.

Retrofit Passive House Construction
Best candidates are buildings which can be approached from the exterior with new siding, windows and roofing. And if the building already needed new roofing or siding, the additional costs of the retrofit are minimized as the labor is about the same. So the primary cost will lie in the added insulation and energy efficient windows. Factory Retrofit Example

Passive-House-Construction-CostsUpon meeting the PH standard, a building needs a renewable system sized to meet the remaining total site energy requirement as modeled in the Passive House Planning Package. The maximum total site energy is approximately 4kWh/(ft2.yr) for certification and will likely be modeled less depending on design. For a 2000 ft2 house, that would be a maximum annual total energy requirement (gas, electric etc.) of 8400 kWh.

In contrast, the average residential consumer in California is paying for over 20000 kWh per year. For a PV system thats a difference between a 15.4 kW versus a 6.4 kW (or smaller) system to achieve net Zero.


Embodied Energy Equity

When the music stops you are covered. The Why ZEPH section described how a Passive House or ZEPH can reduce total ownership costs. But lets take a closer look at how you can unlock what we at the ZEPHER Group call your building’s Embodied Energy Equity. This is the value your building attains over comparable non-PH/ZEPH structures based on future energy costs from a total ownership cost perspective. You are investing in your home, what will the actual payback be?

A Passive House conservatively will save 60 to 70% on your total energy bill over conventional construction. The ZEPH accounts for 100% savings on the energy bills. But the payoff really starts accelerate when energy costs increase. Since 1970, residential energy costs have increased an average of about 7% per year. Based on the energy outlook there is nothing indicating a slowing of rate increases, and it is likely rates will increase at a faster pace. In other words, energy costs will be taking a bigger bite out of your paycheck compared to everything else in the near future. Without a ZEPH or Passive House to inoculate you against these price increases, you may find that you are making a second rent or mortgage payment for energy. 2010’s $600 energy bill may be 2020’s $1500 energy bill. So comparatively, a ZEPH has more value as a result of low total ownership costs.

Bottom line

  • A ZEPH’s Embodied Energy Equity rate of increase is equal to the rate of energy cost increases.
  • A Passive House’s Embodied Energy Equity will increase at a slower pace.
  • You are making an energy futures investment.


The world is changing. Most scientists believe that there is a looming crisis in energy. Let's take a closer look at the economics of this.

The chart above depicts classic energy supply and demand principles.

What happens when the population explodes to 9 billion by 2050 as conservative projections indicate? Energy demand increases and cost of energy goes up.

Many experts believe we are at peak oil now and the world’s readily available oil supply will be gone by 2050 or too expensive to extract. Removal petroleum reserves from the total energy supply will create a huge vacuum in supply that experts are not certain can be replaced by renewables given current demand projections.

The dual threat of both supply and demand problems will lead to conflict, economic at a minimum. The cost of everything related to energy will be affected- Electricity, remaining fossils such as coal, all renewables (wind, photovoltaic, nuclear), insulation materials and yes, even food will sky rocket in price. To counter this, we must invest now in the reaping of the large energy reserve we have in building science efficiency. The ZEPHER Group believes that the ZEPH concept is the best option for meeting the emerging energy void. We envision a future where wasteful, long range distribution networks of energy are a thing of the past and energy production is accomplished in enclaves such as towns, bases and cities that are net Zero or positive, with the smallest net Zero units built as “off the grid” ZEPHs.