There are a variety of energy-efficient materials and building procedures that must be used from the start of the design process in order to achieve net-zero energy performance in high-performance homes. For the most part, builders end up paying more because designers and architects fail to define specific energy-related aspects or fail to make key judgments about energy performance techniques early in the design process. Architecture and design teams working on a zero-energy project must learn about the 12 Steps to a Cost-Effective Zero Energy Home Building and pay close attention to the following design methods, which should be detailed in construction plans as needed, in order to ensure success. By paying attention to these energy-efficiency measures throughout the design phase, building expenses can be kept to a minimum.
Choosing a Location
There should be no obstructions to the sun, flat topography, and limited exposure to the weather for a zero energy house. It would also be close to services, retail, and public transportation. Even if there aren’t many perfect locations, being picky about where you live will save you money and give you a higher quality of life. Access to solar power is very critical. It is possible to have a solar energy contractor conduct a site investigation to ensure that the wall or roof surfaces are receiving enough sunshine and to recommend the best orientation and size of the solar surfaces. A site’s solar access may be less than ideal, as is common. With or without solar access, all of the tactics outlined here can be used to get the house as near to net-zero as possible regardless of how much solar power you have available.
Building Orientation
Orient the building to take full use of seasonal sun angles for passive heating and cooling as well as maximum production of solar energy. Passive solar heat uptake can be maximized in cold climates, while natural shade can be used in warm climates. Direct southern roof orientation is best for solar panels. If a southern orientation cannot be achieved, talk to your solar installer about the best orientation for your region’s climate circumstances.
Climate
Take into account the impact of the climate on the final design. There is no such thing as a one-size-fits-all solution when it comes to climates. Many design features, such as insulation, airtightness, moisture control, and daylighting, must take climate zones and local variables into account. Warmer climates have unique design requirements that should be taken into consideration while creating products.
Design
Rather of many smaller shapes with a lot of architectural intricacies, try adopting fewer, simpler shapes throughout the Consider using fewer, simpler shapes during the conceptual design phase rather than many smaller ones with a great deal of architectural intricacy. The construction, air sealing, and insulation costs will be lower in the field if the building masses are simpler.
Size
Focus on functionality more than resale value when designing small spaces. In a well-designed 900-1,800-square-foot house with well-thought-out practicality, storage, and traffic flow, many smaller families can live very comfortably. Considering that a structure might cost hundreds of dollars per square foot to construct, cutting just a few square feet from the total can save you thousands. With some forethought, downsizing your home can save you money and pay for all of the energy-saving upgrades you’ll need to make it net-zero energy.
Thermal Boundary
Set a clear temperature boundary on your design drawings to avoid any surprises. In other words, you must decide what belongs within and what doesn’t belong there. These places are not part of the conditioned area, for example. If you choose a ducted heating and cooling system, you’ll want to make sure there’s enough room inside the conditioned envelope for all of the system’s components.
Ceilings
Choose between a flat or a cathedral ceiling for the entire house. When the height of a room’s ceiling changes, a wall normally separates it from an unheated area, such as an attic. When it comes to air sealing and insulating this “high wall,” it can be difficult. This wall should have the same level of insulation as other outside walls, and the insulation should be enclosed by hard material. If there is more than one ceiling height, be sure that air sealing, insulation, and stiff backing are all clearly defined.
Roof Overhangs
Create a solar shading system that allows the sun to heat the building when necessary while preventing overheating when it isn’t. One option is to design and construct fixed roof overhangs, especially on the south and west sides that get afternoon sun. The southern roof overhang should be calculated and specified to maximize winter solar exposure while minimizing summer heat. A balance must be made between identical sun angles in spring and fall when heating and cooling requirements differ greatly. As an alternative, consider a 12- to 18-inch fixed overhang and external shading, such as awnings, sun screens, or plants, for a shorter overhang. This will allow for greater spring heat gain and decreased fall heat gain.
R-Values
Include R-values for wall, ceiling, and floor as well as window and door U-values in the plans. There are common R-values of R-30 to R-40 for walls in cold climes, along with ceilings of R-60 and flooring of R-38. It is common for walls to have an R-value of 19, ceilings to have an R-38, and floors to have an R-19 in warm areas. Energy modeling should be used to establish the best R- and U-values for your climate zone.
Convergence of Heat
Avoid thermal bridging by clearly specifying measures on the designs. It’s possible that these include advanced construction techniques including staggered-stud and double-stud framing as well as exterior foam sheathing for the wall, floor, and ceiling systems.
Insulating the envelope
Do not design walls in a way that makes it impossible to cover the insulation with stiff sheets of OSB, Thermoply, or similar materials, and always specify that wall insulation is entirely encased. Soffits, attics, bathtub surrounds, HVAC chases, and fireplace enclosures deserve special consideration. Be sure to add details for enclosing the framing cavity when drafting double-stud walls, such as a plywood cap across the parallel top plates and plywood bucks inside window and door apertures. The ENERGY STAR Raters Field Checklist is an excellent resource for learning about basic insulation and air sealing.
Air Sealing Target
Indicate on plans what level of airtightness you’re aiming for. The number of air changes every hour at 50 pascals (ACH50). Net-zero energy should be attained when you attain 2.0 ACH50 or less..
Systems for an Air Barrier
Decide on the type of air barrier system that will be employed and research it thoroughly. Can drywall be used, will a ZIP System SIGA membrane and adhesive or Aerobarrier be used? Design plans should include information about air sealing materials and procedures.
Directional Blower Door Air Sealing
To find and efficiently seal unexpected air leaks, specify that blower door directed air sealing be performed after ceiling drywall installation and before insulation installation. It’s a good idea to apply this method if you’re trying to reduce your air leakage. Blower door testing isn’t necessary until you’ve mastered the techniques and can consistently attain your goal.
Air Conditioning and Heating Units
Locate all of the HVAC equipment, including the piping, ductwork, and refrigerant lines that go with it. Look for a hot water system and note its efficiency level. Include these in the blueprints and indicate that any openings that might be penetrated must be sealed. Strive to bring the air handler and all ducts within the thermal boundary for ducted systems. Because they use so little energy, ductless mini-split heat pumps are a great option.
Ventilation
Design plans should include mechanical ventilation equipment and ductwork, and the equipment and ducts should be placed as close to the conditioned building envelope as possible. It’s important to keep in mind that heat recovery ventilators require a drain for the condensate that collects. The plans should provide information on equipment efficiency ratings. There are six steps for selecting and designing the correct heat recovery ventilation system, more on this later.
Water Heater
When it’s time to make decisions about the water heater. If your climate is one that relies heavily on heating, put the electric resistance water heater in the center of the conditioned space. If your climate relies heavily on cooling, put it outside. Heat pump water heaters should be placed outside the conditioned room in regions with a volume of about 1,000 cubic feet in climates where heating is predominant. Because they are not heated directly, garages and basements are ideal because they remain comfortably warm throughout the year. There are additional ducting alternatives for heat pump water heaters, so they can be installed within the house. If you use a gas water heater in an airtight house, be sure it has a sealed combustion chamber.
Solar Electricity
Calculate the ideal size of the photovoltaic system based on an accurate energy model to fulfill the home’s energy requirements. In order to attain the zero-energy threshold, make sure there is enough roof area with the right tilt and orientation. Ensure that any roof protrusions, such as chimneys, plumbing vents, or other solar panel obstructions, are placed outside of the roof space allocated for them.
Appliances
Select energy-efficient appliances and their ratings during the energy modeling process and list them on the plans. If you’re looking for energy-saving appliances, search out Energy Star Products. Also, due of their high level of energy efficiency, electric heat pump clothes dryers, and induction stovetops should be taken into consideration.