Home Energy Savings

Building Orientation for Optimum Energy

by Nick Gromicko

Building Orientation for Sun PathBuilding orientation is the practice of facing a building so as to maximize certain aspects of its surroundings, such as street appeal, to capture a scenic view, for drainage considerations, etc. With rising energy costs, it’s becoming increasingly important for builders to orient buildings to capitalize on the Sun’s free energy. For developers and builders, Graphic from EcoWho.comorienting a new home to take advantage of the warmth of the Sun will increase the home’s appeal and marketability. For homeowners, it will increase their indoor comfort and reduce their energy bills.

Thus, building orientation, along with daylighting and thermal mass, are crucial considerations of passive solar construction that can be incorporated into virtually any new home design. InterNACHI inspectors who consult with new homeowners can pass along this valuable information to help their clients reap long-term energy benefits and savings.

Facts and Figures

  • Many older homes’ designs were oriented through the use of a heliodon, which is a moveable light source used to mimic the Sun’s path that hovered over a small-scale model of a proposed building. Today, mathematical computer models calculate location-specific solar gain and seasonal thermal performance with precision, and have the added ability to rotate and animate a 3D color graphic model of a proposed building design in relation to the Sun’s path.
  • Homeowners may now tap into a specialty market of homes designed to spin on their axis in order to follow the hourly and seasonal path of the Sun. These UFO-shaped homes can spin a full 360 degrees in minutes and are built with unusually tall ceilings and windows for maximum efficiency in powering their solar energy system.
  • While some passive solar features are relatively recent innovations, the practice of orienting a home to the path of the Sun is as old as civilization itself. Examples are numerous, from south-facing doors on Neolithic and ancient Ming Dynasty houses, to the astonishing Pueblo ruins in southwestern Colorado.
    The Sun’s True PositionGraphic from EcoWho.com

The Sun’s True Position

Sun's True PositionSchoolchildren (and most homeowners) will tell you that the Sun rises in the east and sets in the west, and, if this were true, building orientation would be a fairly simple matter. In reality, the sun rises and sets in the east and west only on the autumnal and vernal equinoxes, and something very different happens during the remaining 363 days of the year. The Earth’s tilt causes the Sun to rise and set slightly south of east and west in the winter, and slightly north of east and west in the summer. This slight angle depends on the time of year and the observer’s distance from the equator.

As a result, the winter sun spends all of its time in the southern sky, and the summer sun spends much of its time in the northern sky (the sun crosses over into the southern sky during part of the day, depending on latitude). In the Southern Hemisphere, all of these directions are reversed, so the winter sun rises and sets in the northeast and northwest, respectively, and the summer sun rises and sets in the southeast and southwest, respectively.

How the Sun’s Variations in Position Can Affect Building Design

The relative position of the Sun is a major factor in heat gain in buildings, which makes accurate orientation of the building a fundamental consideration in passive solar construction.

Most importantly, a rectangular house’s ridgeline should run east-west to maximize the length of the southern side, which should also incorporate several windows in its design. For this reason, fewer windows should be located on the northern side of the house, where the summer sun can be intense. A deep roof overhang can shade the few windows in this area, as can different types of shade trees and bushes. Research supports an east-west ridgeline. Homes re-oriented toward the Sun without any additional solar features save between 10% and 20% and some can save up to 40% on home heating, according to the Bonneville Power Administration and the City of San Jose, California.

Builders should note that these directions are given in reference to the Sun and not magnetic north, which can vary significantly from the Sun’s actual position. Magnetic north, as read from a compass, can still be used as a reference if the builder adjusts the figure based on the location-specific magnetic variation, which can be found in publicly available maps.

Building Tips for New Construction

The following tips will also assist homeowners and builders in maximizing heat gain through building orientation:

  • Orient the floor plan – not merely the building’s profile – toward the Sun. Design the home so that frequently used rooms, such as the kitchen and living room, are on the southern side. Occupants will appreciate the sunrays in the winter and relief from the sun in the summer. Patios and decks should be built on the south side of the house, where direct sunlight will permit their use for more hours during the day and more days during the year. Likewise, the garage, laundry room and other areas that are less frequently used should be situated at the northern part of the house, where they will act as buffers against cold winter winds.
    orientation-floor-plan
  • Beware of mountains. The north/south sun differential is exaggerated in hilly and mountainous regions, where significant climatic differences can be seen over comparatively small areas. A passive solar house should be constructed on the south-facing slope of a mountain to avoid the extreme shading created where the low-angled sun is blocked by the mountain on the north side. Halfway up the slope is ideal, as the mountain’s peak is exposed to strong winds, while cold night-time air flows into the underlying valley, which is also a natural drainage point.
  • Plan for tree shade. Trees are an important factor in passive solar design because they can both provide needed shade on a balmy summer day and starve the house of natural light when it is needed most. Deciduous trees planted on the south side will lose their leaves in the winter and allow natural light to enter the house, while evergreen trees planted on the north side will provide shade from the summer sun. Builders should carefully consider the age, species, growth rate and mature canopy cover of existing trees before deciding where to orient a structure on a building lot.
  • Install as many windows as possible, but not too many! The exact number of windows required is different for each house because it’s based on – among other considerations – the local climate. A “sun-tempered” house should include enough glazing to equal 5% of the conditioned square footage of the house. Remember, though, that windows allow heat transfer more easily than walls, so too many windows can actually drain heat from the house during the cold winter months.
  • Stray from the rule on east-west orientation, if needed. The east-west orientation of the ridgeline may be adjusted to accommodate other factors by up to 20 degrees with only a minimal impact on heat gain.
  • Driveways can get hot! Driveways and parking lots are made using gravel and asphalt – materials that heat up faster and reach higher temperatures than the rest of the yard. Excessive heat there can spill over to the adjacent house, which is why placement of the driveway or parking lot to the south or east of the building can reduce summer heat buildup in southern climates. During the cold winter months in northern climates, a south- or west-oriented driveway will melt snow faster and provide the home with greater warmth.
  • Glass need not be vertical. Custom glass is available that may be tilted to match the angle of the sun and minimize reflection. Angling glass away from the vertical makes it less insulative, however, so builders should balance potential gains in sun exposure with loss of heat to the outdoors.
  • Another environmental factor that should be considered in the equation of building orientation and positioning is prevailing winds, which are the winds that blow predominantly from a single, general direction over a particular point. Data for these winds can be used to design a building that can take advantage of summer breezes for passive cooling, as well as shield against adverse winds that can further chill the interior on an already cold winter day, or even prevent snow from piling up against windows and doors. Detailed information about prevailing winds for specific locations are plotted in a graphic tool called a wind rose, which is usually available from airports, larger libraries, Internet sources, and county agricultural extension offices. As a general rule of thumb, cold winter winds generally come from the north and west, which can be limited by using insulating glazing on these sides of the house. Also, remember that coastal areas typically experience breezes from an onshore direction, while cool breezes flow down valleys from mountain slopes.

Ultimately, factors such as street appeal and the property’s lot dimensions may restrict a builder’s ability to orient a building in strict accordance with passive solar techniques. Even while working under these constraints, however, a builder can still create an energy-efficient home through the implementation of energy-saving features, such as low-E windows, adequate insulation, air sealing, and cool roofs.

In summary, homes oriented to the path of the Sun with require less energy for heating and cooling, resulting in lower energy bills and increased indoor comfort. Homeowners who are considering new builds should consult an InterNACHI inspector who can meet with them and their builder to discuss ways to maximize low-cost and no-cost energy strategies.

10 Easy Ways to Save Money & Energy in Your Home

home-energy-savingsMost people don’t know how easy it is to make their homes run on less energy. Drastic reductions in heating, cooling and electricity costs can be accomplished through very simple changes, most of which homeowners can do themselves. Of course, for homeowners who want to take advantage of the most up-to-date knowledge and systems in home energy efficiency, we can perform in-depth testing to find the best energy solutions for your particular home.

Why make your home more energy efficient? Here are a few good reasons:

    • Federal, state, utility and local jurisdictions’ financial incentives, such as tax breaks, are very advantageous for homeowners in most parts of the U.S.
    • It saves money. It costs less to power a home that has been converted to be more energy-efficient.
    • It increases the comfort level indoors.
    • It reduces our impact on climate change. Many scientists now believe that excessive energy consumption contributes significantly to global warming.
    • It reduces pollution. Conventional power production introduces pollutants that find their way into the air, soil and water supplies.

1. Find better ways to heat and cool your house.
As much as half of the energy used in homes goes toward heating and cooling. The following are a few ways that energy bills can be reduced through adjustments to the heating and cooling systems:

  • Install a ceiling fan. Ceiling fans can be used in place of air conditioners, which require a large amount of energy.
  • Periodically replace air filters in air conditioners and heaters.
  • Set thermostats to an appropriate temperature. Specifically, they should be turned down at night and when no one is home. In most homes, about 2% of the heating bill will be saved for each degree that the thermostat is lowered for at least eight hours each day. Turning down the thermostat from 75° F to 70° F, for example, saves about 10% on heating costs.
  • Install a programmable thermostat. A programmable thermostat saves money by allowing heating and cooling appliances to be automatically turned down during times that no one is home and at night. Programmable thermostats contain no mercury and, in some climate zones, can save up to $150 per year in energy costs.
  • Install a wood stove or a pellet stove. These are more efficient sources of heat than furnaces.
  • At night, curtains drawn over windows will better insulate the room.

2. Install a tankless water heater.

Demand-type water heaters (tankless or instantaneous) provide hot water only as it is needed. They don’t produce the standby energy losses associated with traditional storage water heaters, which will save on energy costs. Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water travels through a pipe into the unit. A gas burner or an electric element heats the water. As a result, demand water heaters deliver a constant supply of hot water. You don’t need to wait for a storage tank to fill up with enough hot water.

3. Replace incandescent lights.

The average household dedicates 11% of its energy budget to lighting. Traditional incandescent lights convert approximately only 10% of the energy they consume into light, while the rest becomes heat. The use of new lighting technologies, such as light-emitting diodes (LEDs) and compact fluorescent lamps (CFLs), can reduce the energy use required by lighting by 50% to 75%. Advances in lighting controls offer further energy savings by reducing the amount of time that lights are on but not being used. Here are some facts about CFLs and LEDs:

  • CFLs use 75% less energy and last about 10 times longer than traditional incandescent bulbs.
  • LEDs last even longer than CFLs and consume less energy.
  • LEDs have no moving parts and, unlike CFLs, they contain no mercury.

4. Seal and insulate your home.

Sealing and insulating your home is one of the most cost-effective ways to make a home more comfortable and energy-efficient, and you can do it yourself. A tightly sealed home can improve comfort and indoor air quality while reducing utility bills. An InterNACHI energy auditor can assess leakage in the building envelope and recommend fixes that will dramatically increase comfort and energy savings.

The following are some common places where leakage may occur:

  • electrical receptacles/outlets;
  • mail slots;
  • around pipes and wires;
  • wall- or window-mounted air conditioners;
  • attic hatches;
  • fireplace dampers;
  • inadequate weatherstripping around doors;
  • baseboards;
  • window frames; and
  • switch plates.

Because hot air rises, air leaks are most likely to occur in the attic. Homeowners can perform a variety of repairs and maintenance to their attics that save them money on cooling and heating, such as:

  • Plug the large holes. Locations in the attic where leakage is most likely to be the greatest are where walls meet the attic floor, behind and under attic knee walls, and in dropped-ceiling areas.
  • Seal the small holes. You can easily do this by looking for areas where the insulation is darkened. Darkened insulation is a result of dusty interior air being filtered by insulation before leaking through small holes in the building envelope. In cold weather, you may see frosty areas in the insulation caused by warm, moist air condensing and then freezing as it hits the cold attic air. In warmer weather, you’ll find water staining in these same areas. Use expanding foam or caulk to seal the openings around plumbing vent pipes and electrical wires. Cover the areas with insulation after the caulk is dry.
  • Seal up the attic access panel with weatherstripping. You can cut a piece of fiberglass or rigid foamboard insulation in the same size as the attic hatch and glue it to the back of the attic access panel. If you have pull-down attic stairs or an attic door, these should be sealed in a similar manner.

5. Install efficient showerheads and toilets.

The following systems can be installed to conserve water usage in homes:

  • low-flow showerheads. They are available in different flow rates, and some have a pause button which shuts off the water while the bather lathers up;
  • low-flow toilets. Toilets consume 30% to 40% of the total water used in homes, making them the biggest water users. Replacing an older 3.5-gallon toilet with a modern, low-flow 1.6-gallon toilet can reduce usage an average of 2 gallons-per-flush (GPF), saving 12,000 gallons of water per year. Low-flow toilets usually have “1.6 GPF” marked on the bowl behind the seat or inside the tank;
  • vacuum-assist toilets. This type of toilet has a vacuum chamber that uses a siphon action to suck air from the trap beneath the bowl, allowing it to quickly fill with water to clear waste. Vacuum-assist toilets are relatively quiet; and
  • dual-flush toilets. Dual-flush toilets have been used in Europe and Australia for years and are now gaining in popularity in the U.S. Dual-flush toilets let you choose between a 1-gallon (or less) flush for liquid waste, and a 1.6-gallon flush for solid waste. Dual-flush 1.6-GPF toilets reduce water consumption by an additional 30%.

6. Use appliances and electronics responsibly.

Appliances and electronics account for about 20% of household energy bills in a typical U.S. home. The following are tips that will reduce the required energy of electronics and appliances:

  • Refrigerators and freezers should not be located near the stove, dishwasher or heat vents, or exposed to direct sunlight. Exposure to warm areas will force them to use more energy to remain cool.
  • Computers should be shut off when not in use. If unattended computers must be left on, their monitors should be shut off. According to some studies, computers account for approximately 3% of all energy consumption in the United States.
  • Use efficient ENERGY STAR-rated appliances and electronics. These devices, approved by the U.S. Department of Energy and the Environmental Protection Agency’s ENERGY STAR Program, include TVs, home theater systems, DVD players, CD players, receivers, speakers, and more. According to the EPA, if just 10% of homes used energy-efficient appliances, it would reduce carbon emissions by the equivalent of 1.7 million acres of trees.
  • Chargers, such as those used for laptops and cell phones, consume energy when they are plugged in. When they are not connected to electronics, chargers should be unplugged.
  • Laptop computers consume considerably less electricity than desktop computers.

7. Install daylighting as an alternative to electrical lighting.

Daylighting is the practice of using natural light to illuminate the home’s interior. It can be achieved using the following approaches:

  • skylights. It’s important that they be double-pane or they may not be cost-effective. Flashing skylights correctly is key to avoiding leaks;
  • light shelves. Light shelves are passive devices designed to bounce light deep into a building. They may be interior or exterior. Light shelves can introduce light into a space up to 2½ times the distance from the floor to the top of the window, and advanced light shelves may introduce four times that amount;
  • clerestory windows. Clerestory windows are short, wide windows set high on the wall. Protected from the summer sun by the roof overhang, they allow winter sun to shine through for natural lighting and warmth; and
  • light tubes. Light tubes use a special lens designed to amplify low-level light and reduce light intensity from the midday sun. Sunlight is channeled through a tube coated with a highly reflective material, and then enters the living space through a diffuser designed to distribute light evenly.

8. Insulate windows and doors.

About one-third of the home’s total heat loss usually occurs through windows and doors. The following are ways to reduce energy lost through windows and doors:

  • Seal all window edges and cracks with rope caulk. This is the cheapest and simplest option.
  • Windows can be weatherstripped with a special lining that is inserted between the window and the frame. For doors, apply weatherstripping around the whole perimeter to ensure a tight seal when they’re closed. Install quality door sweeps on the bottom of the doors, if they aren’t already in place.
  • Install storm windows at windows with only single panes. A removable glass frame can be installed over an existing window.
  • If existing windows have rotted or damaged wood, cracked glass, missing putty, poorly fitting sashes, or locks that don’t work, they should be repaired or replaced.

9. Cook smart.

An enormous amount of energy is wasted while cooking. The following recommendations and statistics illustrate less wasteful ways of cooking:

  • Convection ovens are more efficient that conventional ovens. They use fans to force hot air to circulate more evenly, thereby allowing food to be cooked at a lower temperature. Convection ovens use approximately 20% less electricity than conventional ovens.
    Microwave ovens consume approximately 80% less energy than conventional ovens.
  • Pans should be placed on the matching size heating element or flame.
  • Using lids on pots and pans will heat food more quickly than cooking in uncovered pots and pans.
  • Pressure cookers reduce cooking time dramatically.
  • When using conventional ovens, food should be placed on the top rack. The top rack is hotter and will cook food faster.

10. Change the way you do laundry.

  • Do not use the medium setting on your washer. Wait until you have a full load of clothes, as the medium setting saves less than half of the water and energy used for a full load.
  • Avoid using high-temperature settings when clothes are not very soiled. Water that is 140° F uses far more energy than 103° F for the warm-water setting, but 140° F isn’t that much more effective for getting clothes clean.
  • Clean the lint trap every time before you use the dryer. Not only is excess lint a fire hazard, but it will prolong the amount of time required for your clothes to dry.
  • If possible, air-dry your clothes on lines and racks.
  • Spin-dry or wring clothes out before putting them into a dryer.

Homeowners who take the initiative to make these changes usually discover that the energy savings are more than worth the effort. InterNACHI home inspectors can make this process much easier because they can perform a more comprehensive assessment of energy-savings potential than the average homeowner can.