Why Should You Build a Net Zero Energy Home

What is a Zero Net Energy Home?

A zero net energy home uses no more energy on an annual basis than it produces. Zero net energy homes are healthy for the environment, healthy for the user, quiet, and comfortable to live in. They can save owners large amounts of money during the year compared to homes built using traditional construction techniques. Zero net energy homes can come in a variety of shapes, size or style and be located in virtually any area if designed properly.

Why Should You Consider a Zero Net Energy Home?

When buying a car, fuel efficiency typically plays a significant role in determining which model to purchase. If our homes require a much higher financial investment, why don’t we consider their fuel efficiency in our purchasing decision? Purchasing or building an inefficient home can result in month after month of high utility bills for the owner, yet we continue to purchase homes with minimal or no knowledge about the homes energy performance.

Buildings use about 39 percent of primary energy usage in our country. Buildings also account for roughly 39 percent of CO2 omissions. It has been shown that carbon emissions and energy use track each other very closely. For instance, if you can reduce energy usage by 10 percent, in theory you could reduce carbon emissions by the same amount.

This means that in order for us to reduce carbon dioxide emissions we must reduce our overall energy consumption. By choosing to design and build a zero net energy home, you will be doing your small part to help reduce our overall carbon footprint.

Going Electric

Direct energy from the sun is the purest form of renewable energy. Unlike natural gas or fossil fuels, the energy from the sun will never run out. This makes electricity generated from the sun a great way to power your house.

Natural gas or fossil fuels are a non-renewable resource. They are available in limited quantities. To use natural gas or fossil fuels typically requires some form of combustion which releases CO2 into the air which adds to our overall carbon footprint. Electricity does not release CO2 into the atmosphere in order to be used. Electricity can also be produced using a standard solar panel system. The electricity produced from your panels can be used to power your home, stored in a battery system, or sent back to the grid to offset your overall energy bill.

Ideally, your home would be powered completely by electricity. Electric appliance and equipment technology is steadily improving, however some feel that the technology is not as dependable/cost effective/or efficient compared to fossil fuel powered appliances and equipment. Also, many people have been using fossil fuel powered appliances and equipment their entire lives. This makes the transition to electric systems much more difficult. We have witnessed performance, efficiency and maintenance issues with electrical appliances however we are optimistic that this technology will advance and become the standard.

How to Design a Zero Net Energy Home

Zero net energy homes utilize passive energy systems and active energy systems.

The first step to designing a zero net energy home is to minimize building energy usage as much as possible. You want to begin this by implementing passive energy systems.

Passive energy systems require no mechanical or operation of components to aid in energy production or energy use reduction. Critical passive systems include a well-insulated and airtight building envelope, proper massing and orientation to take advantage of the summer and winter sun, and lightly colored exterior color/materials. To learn more about envelope construction, check out our article on concrete insulated form construction here. These passive techniques will help your building to use as little energy as possible.

After the passive systems are implemented, you can begin to add active systems. Active systems use ducts, pumps, fans, pipes, wiring, and other mechanical equipment help reduce the overall energy usage and/or provide the little energy that you need to power your home. Examples of active systems would include a solar panel array and/or operable windows. As mentioned above, it is ideal if your active systems all run on electric energy. If designed, calculated, and implemented properly the combination of the passive and active systems should get you close to achieve zero net energy.

Calculating your Total Building Energy Usage

How do you know if your home is zero net energy? To determine if your home is zero net energy, you must calculate your total energy usage and production. (To learn more about calculating energy production and sizing your solar panel system, check out our article here. )

Energy loads on a home can be broken down into component loads. These include heating, cooling, ventilation, lighting, hot water, plug and miscellaneous loads. Each of these component loads should be accounted for in the total home energy usage.

The simplest way to measure energy usage is by looking at the homes energy bills. This is often referred to as operational assessment. Alternatively, you can calculate your homes energy usage through computer modeling software. This will usually require the services of an energy consultant or Architect.

Calculating total energy usage is much easier for buildings that only use electricity. Calculating energy usage becomes more complex when other types of energy such as natural gas and fossil fuels in addition to electricity are used in the building.

To calculate energy usage for homes that use both electricity and fossil fuels, you must convert each energy into a common unit, either the British Thermal Unit (Btu), kilowatt hour (kWh), or kilojoules (kJ). Once each energy type is converted into a common unit, you can calculate the total building energy usage with simple addition.

If you would like more information on designing and building your zero net energy home, please reach out to us here.