June 15, 2013
Have you heard of net-zero? It’s a term that’s being used in architecture, construction and more recently, real estate circles. This month, GreenBridge Architects is gearing up for the design of a new home for future neighbors here in Amesbury, MA, and our clients want to ‘get close’ to net-zero. So we’re booting up our spreadsheets, consultants and specification data to help them get there.
But first, since I’m writing this at the cusp of summer on my sun-filled patio, let’s discuss the perfect margarita. This was passed on to me by my friend and architect Kate Hauserman, who always knows what to drink for the occasion and when to take note of a perfect day.
The Perfect Margarita
1-1/2 oz tequila (Patron is worth it)
1 oz Cointreau
½ oz lemon juice (freshly squeezed – one lemon)
½ cup shaved (or crushed) ice
1) Salt rim of glass: To salt rim, place a thin layer of salt in a small dish or bowl, take empty glass and moisten its rim with a lemon wedge and dip the rim in the salt
2)Place all ingredients in a shaker and shake
3)Strain or serve with ice
Ok, got that out of the way. So with drink in hand….
Net -zero Homes
The Bosch Net Zero Home in Serenbe, Georgia. For more information on this house, see the article at The Great Energy Challenge.
First -What is net-zero? A net-zero home is one that produces as much energy on site as the energy used over the course of a year. Typically energy demand is greatly reduced by construction methods and efficient equipment and energy production is achieved using photo-voltaic systems (PV or solar panels).
Why Does It Matter
Buildings worldwide account for 40% of our primary energy use, and 24% of all greenhouse gas emissions. Achieving net-zero in our homes and buildings will have a major impact on our energy-security and the health of the planet.
How to Build a Net-Zero House
Achieving net-zero requires disciplined decision-making, a systems approach, and larger front-end construction costs. These costs may seem prohibitive for the typical family, but it’s important to remember they are fixed and one-time costs that can be included in your mortgage. In this way, you are paying for your energy costs as part of your mortgage and not in future unpredictable energy bills. The following is a general overview of the four steps involved.
1. Build Only What you Need
A careful design process that aims to keep the footprint small creates a home that has less space that needs to be heated, cooled and lighted (and cleaned!) Multi-use spaces, adaptable spaces planned for changes in the family, and modest, well-proportioned room sizes help to create an efficient home. Sarah Suzanka in her Not So Big House Series offers a wealth of insights and solutions toward building small.
2. Build a Highly Efficient Envelope
Your ‘building envelope’ is everything that separates the inside from the outside: the walls, roof, floor slab, windows and doors. Your mechanical system’s job is to make the interior of your house comfortable by moderating the interior air. An efficient, highly insulated envelope is a separation that allows minimal heat or cooling to move between the inside and the outside, requiring less work (energy) of the mechanical equipment. Less work means smaller equipment and less energy.
3. Reduce energy demand.
-The careful design of your home will include using these same efficient windows that are integral to your building envelope to assist with the reduction of energy demands. Well-placed windows and the architecture and landscape designed around them will at the right times of the year allow the sun to heat and light the room, bring in a cool breeze through heavily shaded trees, or lead hot air up and out of the house.
-Use the highest-efficiency mechanical system and water heating equipment you can purchase. The reduction in demand from steps taken above will help keep the systems smaller. The selection of your equipment should be done with care, with the entire construction and design team factoring all items specific to your home: the design, the site, your energy use, against the efficiencies and costs of available mechanical systems.
-Efficient appliances, water heating, lighting and other electrical equipment are the other big generators of energy demand in your home. Besides the energy used in their function, they create additional heat within the building envelope—heat that your mechanical system then has to use energy to remove in summer months. To reduce demand of these items, install only those appliances you really need and select the most efficient you can afford.
– Gaining control of the “ghost loads”, power used by all those computers, printers, and TV’s and appliances that have lights glowing around the clock, can make or break achieving net-zero. In most homes today, ghost loads can account for around 25% of all electrical power use. Informed appliance selection and the use of timers and power-off outlet strips can help with this feat, as will energy monitoring systems that can track your changes and these extra energy loads.
4. Add Solar
For a net-zero home, you need to now balance the energy ledger, and generate the amount of energy to equal the demand. Solar panels are the most common answer for electrical power, although small wind turbine technology is making wind power equally attractive in some areas. In addition to photovoltaics, solar power can heat not only the water in your hot water tank, but also your whole house, if you use a radiant hot water heating system. All net-zero houses must have some combination of these energy-harvesting systems.
As always, we’d love to hear your comments or questions. You can give us a call at 978-518-2811 or email us at firstname.lastname@example.org.
Thank you to the Green Architect’s Lounge with architects Phil Kaplan and Chris Briley for their seasoned information and inspiring mix of knowledge and drink recipes!
In our next post, we’ll be looking at the installation of a modular home designed by GreenBridge. Happy Summer!