Over the past couple of decades, the home construction industry has been involved in research on how to make homes more energy-efficient. During this time, many new materials and designs have emerged that make it possible to build homes that are more energy-efficient than any other kind of housing built before. The first of these new homes, known as zero energy homes (ZEH), has come on the market, making it possible for homebuyers to purchase a home that is not only easy to live in and comfortable but also costs less to own over a period of time than the typical home today.
Use the Sun for Solar Tempering
The use of solar heat gain through south-facing windows in the winter is a well-established method to reduce energy needs for heating. On the other hand, by blocking the sunlight coming in through those same windows during summer months, cooling energy needs can also be reduced. Solar tempering aims to combine these two functions into a single system. Although slightly more expensive than offsetting HVAC based upon demand or zone-based technology, the cost savings over a 20-30 year period make it an attractive alternative.
Solar tempering provides a cost-effective alternative that involves taking advantage of solar heat gain without increasing window area or cost. It works best when the common living areas and most windows face south. Optimal shading lets in winter warmth and excludes summer heat. Solar tempering provides added light and warmth to the living areas and may reduce heating costs by 10% to 20% without added expense and without risk of overheating in summer. The idea is simple — apply passive solar principles to tempering; that is, collect the sun’s heat during the winter for use in the summer. The process involves using thermal mass (usually stone or masonry) to store heat and release it slowly over a period of several days.
Optimize with Energy Modeling
It is important to consider building energy use early on in the design phase. To ensure that net-zero energy can be achieved, it is recommended to use energy modeling software to determine the performance of a proposed building while keeping costs down. Based on the results, design choices can be made or modified to balance the performance and construction cost of a building, thus optimizing the success of a project.
Super-Seal the Building Envelope
Zero energy homes use special construction techniques and materials that make them extremely efficient at keeping the inside from getting too hot or cold. Super-sealing the building envelope is especially important for these homes because they rely on imports more than other homes do. S, super-sealing refers to air leaks found in the spaces around walls, floors, and ceilings.
To determine the appropriate airtightness target for a rigid or semi-rigid insulation retrofit, perform an energy modeling (ER) to find your current air leakage rate in air changes per hour under 50 Pascals of pressure (ACH50). You can then set a goal between 0.5 and 2.0 ACH50 using a blower door test.
Use Highly Insulated Windows and Doors
Windows and doors are like big holes in a well-insulated, airtight building envelope which are the third most cost-effective opportunity for making a home energy efficient along with sealing up other air leaks. Control window and door heat loss and gain by selecting an appropriate window and door products, carefully locating them, and optimizing their size and orientation. Select appropriate window and door products carefully locating them optimally for best energy performance and always specifying U/V protection.
Select an Energy-Efficient Heating and Cooling System
The heating and cooling system you choose is one of the most important factors for your energy-efficient home. Air source ductless heat pumps, or ‘mini-split heat pumps are currently one of the most energy-efficient on the market today and are without shortcomings of central or forced I have included some examples above that include both positive and negative tones throughout.
Heat Water Wisely
Water heating consumes a large share of a building’s energy budget. That is why it is important for designers and builders to select and locate efficient water heating technology, along with other measures, to minimize hot water use.
There are many factors to consider when it comes to evaluating the cost-effectiveness of a solar thermal system, but if your home provides hot water for more than 5 people and will continue to do so for the next 20 years or so, then it is a good idea to get an estimate on the costs involved. Homeowners who live in small homes will discover that the upfront cost to install an energy-efficient, electric heat pump water heater, along with enough solar power capacity to run it, will be much lower.
Install Energy Efficient Lighting
Energy-efficient homes use LED lighting to minimize energy while optimizing light for residents. LED lights typically cost less than halogen and compact fluorescent (CFL) bulbs and last much longer. LEDs also don’t contain mercury like CFLs, which makes them safer to use for those concerned about environmental health. Lighting is the most efficient way to naturally illuminate a room at a time of day when the sun isn’t always out. The wrong light can lead to an unpleasant experience, but the right light can accommodate a home’s style and purpose. Take advantage of the light to ensure your home strikes the right tone for any occasion. LEDs are one of the most energy-efficient options when it comes to residential lighting. Determining the optimal light fixtures, placement, and control of natural light can significantly lower energy expenses.
A skylight is a roof-like structure that can bring light deep into interior spaces. Skylights have strong pros and cons. On the positive side, they bring natural light deep into interior spaces that may be dark. This can greatly improve occupant comfort and reduce electric light use. However, skylights have strong negatives too. Skylights represent holes in the home’s exterior surface that have the highest insulation level. Skylights can be an attractive feature for a home. However, they can also be serious energy and indoor air quality issue. The primary drawback of skylights is that they require more expensive roofing materials and they require significant added framing to support them. Also, skylights always face up, which means the sides are open to air infiltration, and in the winter, they allow heat to escape through cold roofs. In the summer, skylights allow solar gain to pass through. You might be surprised to learn that skylights work best in moderate coastal climates where the building is surrounded by water. If you happen to live in a sunny, desert climate or in a place without a lot of cloudiness, you probably shouldn’t use skylights.
Use the Sun for Renewable Energy
Grid-tied solar PV panels currently provide the most cost-effective form of renewable energy for a zero energy home. They can power all the energy needs of a home including lighting, heating and cooling systems, appliances, and hot water. However, they are the most expensive component of a zero energy home and strategies for reducing or mitigating those costs are important to consider.
Ideally, you’d choose a site with uninterrupted sunlight during the hours of 9 am and 4 pm for your solar panels. The south or west roof should have enough square footage to hold the number of solar panels needed. Any obstructions on the home that will cast a shadow on the panels or interfere with their placement should be eliminated from the design. Due to the relative expense of solar electricity, it is important to ensure that your panels receive as much exposure to sunlight as possible. Locate your panels so any obstructions – including dormers, chimneys, plumbing vents, and utility masts – are not in their direct path and are 3 feet or more away from the edge of the solar panel.
Select Energy Efficient Appliances and Electronics
Since a zero energy home uses highly efficient building materials, high-efficiency heating and air conditioning equipment, and appliances, a new category, appliances, and electronics, becomes the most significant source of energy expenditure in zero energy homes. As a result, selecting high-efficiency appliances and electronics becomes the final step needed to minimize home energy use.
An induction cooktop heats 30% more efficiently than a gas range and about 12% more efficiently than an ordinary electric range. Induction cooktops also heat more quickly than either electric or gas ranges. Induction cooktops heat the molecules in the pan rather than heating the cooktop itself. When cooking is done, the surface cools and becomes safe for cleaning, so it’s easy to maintain this unique heating appliance. However, gas stoves produce emissions that may exceed EPA standards for indoor air quality, so it’s best to only install them in homes with appropriate ventilation.
Microwave ovens use significantly less energy than electric or gas ovens. Microwave ovens should be sized to accommodate cooking the majority of foods cooked in your kitchen. There are many recipes and techniques for cooking a wide variety of foods in a microwave.
Create an Energy-Efficient, Fresh Air Supply
Zero energy homes are considerably more airtight than standard homes. This tightness requires a continuous source of fresh, filtered air and moisture control. These energy recovery ventilation systems, which are among the most efficient of all HVAC system types, expel stale air while recovering its heat and returning that same heat to the home with the fresh air.