A little technical information

Net Zero

A net zero or zero net energy home is a home that makes all the power in consumes on site, but remains connected to the grid (utility). These homes can have energy storage (batteries) and or a generator, but do not depend on these modalities for backup power. They uses the grid for that purpose. 

During times of high solar production (peak sun hours) the photovoltaic (solar electric) system produces more power than the house consumes and then “banks” the power to the grid, essentially turning the utility meter backwards. The utility serves as your battery. Battery systems can be incorporated into these houses to supply power when the grid (utility) is not delivering power. Selling schemes that use time of day rate advantages to determine when to sell power to the grid can create cost leverage for the homeowner with battery systems as utility rates can vary depending on time of day. A generator can be incorporated into these systems for extended periods of grid outages. 

Energy efficiency

The most sustainable, affordable and practical way to save energy is to not use it. The less energy your home consumes the less your energy costs will be. An efficient home uses less power to deliver the same convenience and comfort as a more wasteful home.

Any house can make all the power consumed within it with unlimited real estate and resources with, and on which to build, an enormous photovoltaic  system. A more efficient home will require less power and therefore a smaller photovoltaic system to power it. When battery systems are incorporated into these homes this becomes exponentially more important. ZED builds the most efficient, comfortable houses by following Passive House Institute US protocols and energy modeling.

We work to achieve different levels of energy independence in homes depending on owner requirements and budget. Any degree of energy independence can be achieved, but the levels mentioned herein represent targets we commonly achieve.

Off-Grid or Zero Grid

An off-grid home is a  home that is totally energy independent. This highest level makes all the energy consumed in the home on site. Generally, an off-grid home is not grid (utility) interconnected. The main energy source is a photovoltaic (solar electric) system with an energy storage (battery) system. Often a generator is included to charge batteries during extended periods of low solar production as is often the case in winter. A generator can reduce the size of the PV and battery system, and extend the system autonomy greatly, running minimal time charging or topping off the charge of the battery system in times when peak solar production is insufficient to fully charge the system.

Off-grid homes can range from large palatial compounds to small conservative homesteads. At any scale, efficiency is key to making the home function fully in a normal manner with all the comforts and amenities of a modern home. 

Partial solar powered home

A partially solar powered home is just what it sounds like. The home makes some percentage of its power with its on-site photovoltaic system. These are the most common solar homes today. Some PSP homes utilize a battery system to supply back up power for times when the grid (utility) is not delivering power. A generator can be incorporated into these systems for extended periods of grid outages.

What’s in it for You

Health and indoor air quality

To improve indoor air quality, it is important to minimize sources of indoor air pollution and provide ventilation to bring fresh, filtered air into the home and exhaust stale contaminated air. Mechanical ventilation is especially important in houses with a tight envelope because little air exchanges between the interior and exterior of the home passively. Sub slab depressurization systems can be incorporated to prevent radon from entering the house. Detached garages can’t seep pollutants into the home as they are not connected to the home. Electromagnetic frequencies are emitted by transmitters outside and inside the house. Typical electrical wiring also emits EMFs. Shielding from these emissions can be designed and built into homes.

Quiet

The use of thick exterior walls and roof with dense insulation and back vented cladding combined with high quality triple glazed windows and multi sealed windows and doors creates an interior environment that is noticeably far more quiet than normal houses.

Comfortable

The combination of all the construction details make these houses more comfortable than ordinary houses.

Safe

The use of fire resistant mineral wool insulation and elimination of air movement through wall and roof cavities and interstitial spaces renders the house far less susceptible to fire and greatly slows fire spread. Mineral wool will not burn.

Secure

Energy security means that you will not loose power and some predetermined percentage of your energy costs will be fixed up to 100 percent for decades to come. Storms, fires, earthquakes, cyber hacking, and poor planning have all become more frequent in recent years leaving households without electricity, heat, water, and cooling  often for weeks. The loss of refrigerated and frozen food, the convenience of hot water and heat disrupt daily routines and represent significant unnecessary expense. Increases in energy prices both at the electrical meter and at the fuel pump also represent additional expense which over time amount to very significant losses. PV systems with battery back up and or generator redundancy back up can eliminate all of that insecurity.

Durable

Condensation is a reality of any climate with relative humidity beyond the dew point. Dew point is a function of temperature and relative humidity. When the air is saturated condensate will form on condensing surfaces or any solid surface below the temperature of dew point at that relative humidity. This means that in many circumstances at many times throughout the year water will fall out of the air and deposit inside cavities on inner wall surfaces. Wet wall surfaces promote rot, decay, and mold growth. This wetting of walls from the inside out is a very destructive force. It is avoidable with careful design. As an example, air conditioned structures in humid outdoor air have cool inner wall surfaces. When humid outdoor air comes in contact with the first surface below dew point which would be the inner wall surface, water will condense on that surface. Judicious use of materials that remain vapor permeable and materials that are less susceptible to moisture damage and do not have a nutrient source for mold in wall construction will not decay or grow mold the way typical building methods and materials will.

Economical

Return on additional investment to build a zero energy home over the cost of code built homes is usually recognized fully in under 15 years. The additional cost of building a far superior structure using Passive House modeling is often only five or six percent higher than building a code compliant house.

Sustainable

Low energy use or positive energy production removes the home from the fossil fuel economy providing decades of pollution free on site distributed energy reducing its carbon footprint greatly. Materials in the home are sourced locally whenever possible and many materials used are carbon sequestering materials retaining carbon for the life of the home. We use as little high carbon embedded materials as possible. Avoiding the use of concrete and steel and substituting less carbon intensive materials with equal or superior performance represents a giant leap toward a sustainable future and a livable world for generations to come.

Beautiful

We strive to build beautiful homes that are environmentally appropriate and fit well within the neighborhood and their surroundings. Beauty gives great pleasure and a beautiful living environment gives pleasure day after day over the long term. This consistent pleasure adds greatly to personal wellbeing and is a source of pride. Pride in ones home leads to the desire to maintain and care for the home which promotes a healthy environment and greater longevity for the home itself as well as for the occupants.

New Construction

Design and Build

We design and build houses in a manor that is more sustainable than common practice in the building industry. We aim to satisfy the triple bottom line. The goal being that building creates value for all stakeholders; people, planet, and profit.

We build taking into consideration the environmental impacts of sourcing materials, construction, operating the house, and eventual de-construction, re-use, and re-cycling of the resources used in the structure. We also consider the functionality of the structure for the occupants such as health, comfort, safety, economics, and convenience. Durability and longevity play a tremendous role in the long term sustainability of the structure and the society into which it is built. We assure through the careful design process unsurpassed durability and longevity. Our purpose is to build the best possible house and reduce the carbon footprint of that house while providing outstanding value to our clients, paying our labor force a living wage and recovering a profit.

Build your designs

We are happy to work with your architect or we can rework a pre-existing plan set to achieve some degree of green building and energy independence depending on the original design, sitting, and budget.

Manage your building project

Acting as your agent we will obtain permits, create a schedule, hire contractors, oversee your project from original concept through to final commissioning. We co-ordinate your entire building project allowing you any amount of involvement you are comfortable with. We can reduce your overall building expenses by allowing you to serve as the general contractor while we handle the tasks of managing sub-contractors, keeping on budget and schedule, insuring quality control, inspection completion, and testing performance.

Energy systems

Photovoltaic systems (solar electric)

We provide integration of photovoltaic modules (panels) into your existing electrical service sized to meet your projected energy demands. Photovoltaic energy systems have no moving parts and produce energy for more than twenty years with little maintenance.

A residential solar energy system will cut or eliminate a homeowner’s electric bill. With electric costs outstripping the rate of inflation, a solar electric system generates value today and security for tomorrow. When you produce more solar power than your home uses, the solar electricity flows back to the grid, making your meter spin backwards and earns credit against your consumption reducing your balance with the utility company. State and federal incentives typically cover 40%-60% of the cost of installation of a solar electric system. The final net cost of a solar installation is paid back early in the lifetime of the equipment. This strong return on investment makes going solar one of the smartest home improvement decisions you can make. Solar homes sell faster and at a higher value than homes totally dependent on the grid. Modules are warrantied for 20 years and produce power for much longer.

Why would you want to rent energy for a lifetime when you can own your own endless source of free energy.

Energy storage systems (batteries)

ZED recommends battery banks using lithium iron phosphate  chemistry. Lithium ferro phosphate (LFP) is a type of lithium ion battery that functions with little loss at low temperatures. It can be discharged to very low states of charge allowing considerably smaller battery banks. They are rated to deliver 6,000 cycles at 80% depth of discharge allowing 16 years of service and are warrantied by the manufacture for 10 years. They do not suffer from thermal run-away as do other lithium ion modalities. They don’t produce toxic fumes or fumes of any sort and do not require ventilation. Lithium Iron phosphate batteries are very robust. Energy storage is energy security.

Generator sets

We match generator engine sets to customer load and expected demand to reduce the size of PV and storage systems and provide extended autonomy for times when PV is off line for multiple days. A gen set will reduce the size PV and battery systems needed in winter months by half or more and only run a few hours per day during the least sunny, snow covered months.

Vehicle chargers

Fuel your vehicle with sunshine. An electric vehicle powered by an on-site PV system will have very low carbon emissions. There is embodied carbon in the manufacture of the automobile but operationally, embodied carbon from the manufacture of replacement tires and batteries will be the only major carbon emissions. Don’t pay for automobile fuel, use free energy gifted to you daily from the sun. No combustion, no carbon.  Drive green.

How to Build ZERO

Off Grid, Zero Net Energy, and High Efficiency housing isn’t rocket science and it doesn’t require an Einstein to plan. It is however a little more complicated to reach a satisfactory result than in today’s code compliant construction. The building is a series of interrelated and interconnected systems that should be integrated to work together to perform well as one unified functioning system.

Traditional contractors do not always follow these prescriptions. Many are unaware of the physics that require and dictate this planning and others are not meticulous in their assembly processes. Very few contractors and builders test and inspect during and after the build process. Testing air sealing during the building process is paramount to assuring a tight building envelope (enclosure). 

After the building envelope is completed it is far more expensive to implement the measures that make the building an integrated functioning system. Poorly designed and constructed buildings can not perform at this level and will not be as durable as well-designed, meticulously constructed complete building systems.

Appropriate building siting (compass direction various facades face) is essential to utilize naturally occurring environmental factors to create comfort within the building without requiring excess energy to overcome the environmental influences working on the building. In other words, situate the structure on your site well.

Follow these simple guidelines:

Window placement

This is more that just getting an eastern exposure. Window selection sizing and orientation must be consistent with site requirements and appropriate shading must be provided for south, east, and west facing windows. Appropriately sized and placed overhangs shade south facing windows in summer months reducing solar heat gain but allow solar heat gain in winter months.  Deciduous trees provide similar benefits for east and west facing windows.

Foundation

Foundation, basement, or slab insulation, or at minimum slab edge insulation is required and must be properly sized and placed. Back spaced exterior wall cladding (siding) and roofing is required in most situations to promote drying.

Walls

Walls and roof must have continuous insulation with no thermal bridges or bypasses. All control layers must be located and oriented within the exterior building assemblies properly and must be continuous. Rain screens and open drainage planes must be properly placed and be continuous.

Fenestrations

Window and door (fenestration) flashings and connections are critical. All control layers must be joined to corresponding control layers in the walls to form continuous layers within the enclosure.

Water control

In all structures water, (vapor liquid and solid), is the most destructive element in the built environment. Without proper planning and execution, well-sealed and insulated homes can cause as many problems as the leaky, poorly insulated housing stock commonly found throughout this country. 

Problems in high efficiency homes are different than those in standard homes and must be addressed from the planning stage through to final commissioning.

As we seal the house from infiltration and exfiltration and reduce thermal transfer between interior and exterior, ventilation and moisture mitigation become critical as there is no air movement through walls, roof, windows and doors, holes, and cracks. Moisture can no longer be carried into or out of the building by air currents. The lack of energy movement through well-insulated walls and ceilings does not drive vapor out of these assemblies sufficiently unless material selection has been carefully made to allow easy vapor permeability.

Air

Stale breathing air is not passively exchanged with fresh outdoor air in well air sealed structures and requires mechanical ventilation. Oversized heating and cooling devices work inefficiently and fail to regulate humidity. Class two and class three vapor diffusion retarders must be properly placed in wall and roof assemblies. Ventilation systems must be sized properly and accommodate enthalpy (heat and humidity) recovery. Appropriate heating and cooling equipment must be sized properly for the building envelope and occupants.

Appliances

Appliances and lighting must be carefully planed and selected to reduce energy consumption vapor emission and eliminate combustion byproducts.

Solar Energy

Adding a photovoltaic system sized to make all the energy needed to power the house and occupant use habits will result in a net zero energy home. The actual energy use in a home is driven only partially by the structure itself, the climate and more specifically the weather. The occupants and their habits are the other driver of energy use. ZED can estimate energy use quite accurately by close examination and calculation of past energy use habits of the occupants and looking forward to include future use patterns.

Environmental Benefits

Avoid the expenses of major power blackouts. Loss of productivity, comfort, stored food, and access to clean water are all common results of power loss. In the last few decades we have faced ever greater power blackouts. Most have been caused by human utility operator error however increasingly more frequency of poor planning, cyber issues, climate related issues, and infrastructural issues have caused extended blackouts many lasting up to 16 days. Our aging infrastructure, the increasing demand for energy, international political instability, unforeseeable and foreseeable catastrophe, and climate change continue adding to our ever worsening energy insecurity. Build energy independence. Go zero!

What you can do

Be responsible!

1) Do not support the commercial nuclear industry until generation 4 nuclear power plants are a reality. Gen 4 reactors consume the radioactive fuel to a point where it can be disposed of at a sub natural transuranic level. This technology may prove to be the answer to the ever increasing radioactive storage problems we are facing now. It also offers a long term solution to the massive energy needs of the future world population. Research and development in Gen 4 nuclear power should be supported.

2) Do not burn fossil fuels. There is no clean coal, clean oil, or clean natural gas. These are slogans invented by fossil fuel company marketing teams to represent lies enabling the continuation of their obscene profits at the expense of your health and future and moreover the health and future of future generations.

3) Lower your carbon footprint.

4) Build only as large as you need. Don’t waste resources.

5) Build using materials with low embodied carbon or negative embodied carbon (carbon sequestering materials).

6) Limit use of materials with high global warming potential, ozone depletion potential, carcinogens, and toxins.

7) Source materials locally.

8) Use construction scrap as thoroughly as possible.

9) Recycle unusable scrap.

10) Make most or all the energy you use at the point of use with renewable energy sources like photovoltaics (solar electric).

11) Make most or all of your transportation energy using renewable energy to charge and drive an electric or hybrid electric vehicle.

Glossary

Learn more!

Air sealing: Air sealing is the process of stopping or preventing uncontrolled air movement into and out of a structure (infiltration and exfiltration) through holes and cracks in walls roofs and foundations.

Building envelope: The building enclosure including foundation walls roof windows and doors.

Carbon dioxide equivalent: is calculated from GWP For any gas it is the amount of heat absorption equivalent to the same volume of CO2. CO2 has a value of 1. R 134a, a commonly used refrigerant has a CO2 equivalent of 1,430 for the same volume of CO2. 

Carbon footprint: A carbon footprint is the total greenhouse gas emissions caused by an individual, event, organization, service, or product, expressed as carbon dioxide equivalent. This includes the entire life cycle of the entity or endeavor from cradle to cradle (original harvesting or extraction of a resource to the eventual deconstruction re-use and or re-cycling of that resource).

Carbon negative: a home with embedded carbon sequestering (wood and forest product or cork insulation) greater than that expended in manufacture and functioning.*

Demand response: A response to maximum loads placed on a power source (usually the utility grid). Often demand response involves shutting off loads (like air conditioners in summer afternoon hours) but can also refer to selling excess power from a micro or nano grid to a utility during peak load times.

Distributed energy: is energy produced at the point of use or close to it, as opposed to centralized production as is the modality used by the utility grid, requiring miles of transmission lines and extensive infrastructure.

The energy losses due to resistance are 50% to 65% of the utility energy produced. Maintenance of the grid infrastructure is enormously expensive and the US grid is out of date requiring billions of dollars to update and upgrade. The out of date grid is under sized for current load so brownouts and blackouts are an ever increasing occurrence. Cyber threats pose additional insecurity to the centralized grid.

Electric grid: An interconnected network of electrical power generation, transmission, and distribution infrastructure to deliver power from producers to consumers traditionally from utilities to end users. (utility grid)

Energy positive: a home that produces more energy than is used, often selling power to the grid during high demand times.*

Energy recovery ventilation: (ERV) A system that exhausts stale air and takes in fresh outdoor air while removing energy (heat and humidity) from outgoing air and adding that energy to the incoming air.

Embodied carbon: is the amount of carbon emitted to the atmosphere in the extraction, harvesting, manufacturing, transportation and use of a material, product, or activity.

Fenestrations: Doors and windows.

Global warming potential: (GWP) is the heat absorbed by any greenhouse gas in the atmosphere, as a multiple of the heat that would be absorbed by the same mass of carbon dioxide (CO2). GWP is 1 for CO2. 

Green building: both a structure built to place small demands on the earth, and finite resources and also the application of processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from planning to design, construction, operation, maintenance, renovation, demolition, and the re-use and re-cycling of the resources used throughout the entire life cycle of the building.

Grid Independent: a home that produces all the energy they use and stores energy for use during low energy producing times. Usually connected to the grid for backup power and or for sale of excess produced energy to the utility.*

HERS rating: Home energy rating service assessment of home energy performance providing third party certification. Resnet HERS index - and listing in the HERS registry

Load: The energy required to power a device. Electrical loads are expressed in watts or kilowatts, heating loads are expressed in BTUs per hour.

Microgrid: A mid sized energy supply and distribution network suitable for a large business a campus a town or a city. A microgrid is isolated from the utility and is insulated from the problems of the utility grid. It can operate independently or in conjunction with the utility grid and is secure against catastrophic power outages, brownouts, surges, rate fluctuations and rate increases. Often a microgrid includes diverse power sources and energy storage.

Nanogrid: A small energy supply and distribution system suitable for a small business or a residence. A nanogrid is isolated from the utility and is insulated from the problems  of the utility grid. It can operate independently or in conjunction with the utility grid and is secure against catastrophic power outages, surges, and rate increases. Often a nanogrid includes diverse power sources and energy storage.

Negative embodied carbon: materials with more carbon sequestered within than embodied carbon required to produce them.

Net metering: A electrical metering modality whereby the electrical meter is capable of metering electrical flow in two directions allowing power to be purchased from a supplier (utility) and to be sold back to that supplier in times when the consumer/producer has produced excess power crediting them for power produced on site and thereby reducing or eliminating that consumer/producers bill.

Off-grid: a home that produces all the energy they use and stores energy for use during low energy producing times. Not usually connected to the grid.*

Ozone depletion potential: (ODP) The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause.

Passive house: a home built to the highest standard of energy efficient enclosure. Several organizations certify Passive Houses. We follow the Passive House Institute US standards and use WUFI Passive energy modeling software and protocols.

Peak load: the electrical current total required by combined loads running simultaneously at that point in time when maximum energy is needed.

Peak Sun Hours: The equivalent number of hours per day when solar irradiance is 1000 w/m2 (watts per meter square). For example, four peak sun hours per day means that the total energy received during daylight hours equals the energy energy that would have received if the irradiance had been 1000 w/m2 for four hours.

PV (photovoltaics): Solar electrical production based on the conversion of photons from solar radiation into electron flow. Harvesting free energy from the sun to power your loads.

R value: The resistance of a material to thermal conductivity

Sacrificial layer: is a layer in a building that is meant to be removed and replaced periodically. House interiors age and many components become unserviceable. Plumbing fixtures, electrical services, windows, and even walls become damaged and in need of replacement. The period between renovations is often 50 to 100 years.  

Sustainability: As defined by the Bruntdland Commission in its report “Our Common Future” sustainability is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Sustainability is a holistic approach that considers ecological, social and economic dimensions, recognizing that all must be considered together to find lasting prosperity.

Thermal bridging: A thermal bridge, also called a cold bridge, heat bridge, or thermal bypass, is an area or component of an object which has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer.

Triple bottom Line: The US Green Building Council speaks to the triple bottom line a term coined by John Elkington in his 1998 book Cannibals with Forks, a concept incorporating a long term assessment of potential effects and best practices for three kinds of resources: People, Planet, and Profit. 

U factor: The thermal conductivity of a material

Zero carbon: a home that sequesters as much carbon as is expended in manufacture and operation.*

*All these descriptions define different levels of sustainability and energy independence. 

*Most situations require some compromise and/or combinations of methods, standards and systems to meet client requirements.