Residential Efficiency Measures

New Homes

New Homes

Read NCAT’s New Home Buyers Guide to Energy: Montana Residential Buyer’s Guide

Energy-Efficient New Homes
Are you an architect, builder, or Realtor looking for a way to make the houses you design, build, or sell more appealing to potential clients? Or perhaps a consumer planning to build a new home? One of the smartest decisions you can make is to incorporate both ENERGY STAR standards into the home’s design. ENERGY STAR labeled homes are independently verified to be typically 20 to 30 percent more efficient than standard homes. So before you begin your new construction project, check out the features and benefits of an ENERGY STAR qualified home!

(source: ENERGY STAR Program) A new home or apartment that has earned ENERGY STAR® has undergone a process of inspections, testing, and verification to meet strict requirements set by the US EPA. ENERGY STAR certified homes and apartments use significantly less energy than typical new homes and apartments while delivering better comfort, quality, and durability.

Better for your pocketbook
ENERGY STAR homes are at least 15% more efficient than code-built new homes, making them some of the most energy efficient homes on the market today. By using less energy, ENERGY STAR homes cost less to operate, which means more money in your wallet month after month. Combined with potential higher resale values, ENERGY STAR homes represent a smart investment.

Better heating and cooling
Enjoy a home with even temperatures throughout the year. Tightly-sealed ductwork, high-performance windows and properly installed insulation make your home more comfortable.

Better for the environment
The energy used by American homes accounts for 20% of total U.S. carbon dioxide (CO2) emissions. ENERGY STAR certified homes perform better than standard code-built homes and require less energy for heating, cooling and hot water. This amounts to reduced air pollution and a healthier environment for everyone.

Better for you
ENERGY STAR Homes have Healthier indoor air, as performance-tested ductwork keeps the air inside your home clean by reducing the possibility of drawing unwanted air from your home’s attic, basement, crawl spaces and garage.

To learn more about what makes a home an ENERGY STAR Home, visit our ENERGY STAR Home Features Overview section.

In order for a home to be certified as ENERGY STAR, it must be inspected by a trained Verifier. The Verifier will ensure that the home meets strict construction and performance requirements, providing peace of mind for home buyers. Without the inspection, the home cannot be labeled ENERGY STAR. Search for ENERGY STAR Verifiers.

Add Solar To Your ENERGY STAR Home
You can save even more money, and further reduce your impact on the environment, if you incorporate solar energy into your new ENERGY STAR home.


Lighting and Daylighting

Lighting adds to the aesthetics and usability of any home. It is also “power hungry,” accounting for nearly 15 percent of the average home’s electric bill. Fortunately, homeowners can take easy, relatively inexpensive steps to reduce the cost and energy consumed in lighting their home. Using energy-efficient lights, fixtures, and controls can have a significant and favorable impact on home lighting costs. New lighting technology can provide energy savings of 50 to 75 percent.

A variety of lighting product choices are available to the homeowner:

light bulb comparison chart

Solid State Lighting

The next frontier of lighting technology is solid state lighting (SSL) utilizing light-emitting diodes (LEDs) or organic light-emitting diodes (OLEDs).

  • LEDs have been around since the 1960s, but they are just now reaching the levels of luminous output and power that open the door to more applications. For example, today’s commercially available LEDs offer energy efficiency, maintenance savings, impact resistance, durability, and other benefits for traffic signals, exit signs, and other specialty applications. White LEDs are approaching performance levels that make them attractive for use in automobiles, aircraft, and elevators. For most general illumination applications, however, current LEDs cannot yet compete with traditional sources in performance or cost.
  • OLEDs are based on organic (carbon based) materials. In contrast to LEDs, which are small point sources, OLEDs are made in sheets which provide a diffuse area light source. OLED technology is developing rapidly and is increasingly used in display applications such as cell phones and PDA screens. However, OLEDs are still some years away from becoming a practical general illumination source. Additional advancements are needed in light output, color, efficiency, cost, and lifetime.

More research is needed to increase the efficiency and decrease the cost of SSL technologies. Leading this research is a Solid State Lighting partnership between the U.S. Department of Energy (DOE) and the Next Generation Lighting Industry Alliance (NGLIA). The Department of Energy’s solid-state lighting R&D plan spans 2000 through 2020. It includes core technology research, product development, and commercialization efforts focused on SSL.

Learn More

The DOE Solid-State Lighting Portfolio contains information about the field of solid-state lighting along with currently available LED products.


The oldest and most common lighting product is the incandescent lamp or light bulb. It accounts for about 85 percent of indoor home lighting. Incandescent lamps emit light when electricity flows through and heats a metal tungsten filament. Incandescent lamps are popular due to their low cost, warm light, and excellent color rendition. They light up instantly and can be used with a dimmer switch. However, when compared to other lighting sources, they have a short life, generate more heat, and produce less light per watt of energy.


Fluorescent lamps produce light when an electric current passes through mercury and inert gasses. They require a ballast to regulate the current and provide the high voltage pulse needed for start-up. The use of electronic ballasts to replace standard and electromagnetic ballasts has increased the energy efficiency and eliminated the flicker and noise of this type of lighting. Fluorescent lamps use only 25 to 30 percent of the energy consumed by incandescent lamps to provide the same amount of illumination. Fluorescent lamps also last about 10 times longer than incandescent lamps. These benefits and improvements in the color rendition and temperature of fluorescent lamps have expanded the applications for this type of lighting.

Compact Fluorescent Lamps (CFLs)

Compact fluorescent lamps combine the energy efficiency of fluorescent lamps with the convenience and popularity of incandescent lamps. CFLs can replace incandescent lamps with three to four times the wattage, saving 75 percent of lighting energy. While CFLs can cost 3 to 10 times more than incandescent lamps, they last 6 to 15 times longer. This longer life combined with significantly lower energy use more than offsets the higher initial price of CFLs. These lamps work much like a standard fluorescent and contain a ballast and gas filled tube. They are designed to screw into a lighting fixture just like standard incandescent lamps. Most CFLs are designed for indoor use, although several outside models can function in colder temperatures. CFLs are especially beneficial in areas where lights are left on for long periods of time. Because of their long operating life, CFLs are ideal for hard-to-reach areas. Learn more.


Daylighting is the use of windows and skylights to bring more natural light into a home. It is the perfect complement to energy-efficient home lighting. Daylighting reduces energy demand for interior lighting. Homes that actively incorporate daylighting will be less reliant on artificial indoor lighting during the day and will enjoy quality, natural light. Maximum benefits from daylighting are best obtained when it is integrated into the design and siting of a new home. It can also be used during the renovation of an existing home.

Learn More

Look for more information about new lighting technology, including the types of lighting available and energy saving lighting controls, in the Consumer’s Guide to Energy Efficiency and Renewable Energy.

An additional source of information on energy-efficient lighting products can be found at the ENERGY STAR® program. ENERGY STAR, a joint program of the U.S. Environmental Protection Agency and the U.S. Department of Energy, helps consumers save money and protect the environment through energy-efficient products and practices. The ENERGY STAR website includes useful information about lighting.

Heating and Cooling

Read NCAT’s Residential Mechanical Ventilation Handbook and Heating & Cooling Buyer’s Guide

Heat & Cool Efficiently

As much as half of the energy used in your home goes to heating and cooling. So making smart decisions about your home’s heating, ventilating, and air conditioning (HVAC) system can have a big effect on your utility bills — and your comfort. Take these steps to increase the efficiency of your heating and cooling system. For more information, see our Guide to Energy Efficient Heating & Cooling (708KB).

Change your air filter regularly

Check your filter every month, especially during heavy use months (winter and summer). If the filter looks dirty after a month, change it. At a minimum, change the filter every 3 months. A dirty filter will slow down air flow and make the system work harder to keep you warm or cool — wasting energy. A clean filter will also prevent dust and dirt from building up in the system — leading to expensive maintenance and/or early system failure.

Tune up your HVAC equipment yearly

Just as a tune-up for your car can improve your gas mileage, a yearly tune-up of your heating and cooling system can improve efficiency and comfort. Learn more:

Install a programmable thermostat

A programmable thermostat is ideal for people who are away from home during set periods of time throughout the week. Through proper use of pre-programmed settings, a programmable thermostat can save you about $180 every year in energy costs.

Seal your heating and cooling ducts

Ducts that move air to-and-from a forced air furnace, central air conditioner, or heat pump are often big energy wasters. Sealing and insulating ducts can improve the efficiency of your heating and cooling system by as much as 20 percent — and sometimes much more.

Focus first on sealing ducts that run through the attic, crawlspace, unheated basement, or garage. Use duct sealant (mastic) or metal-backed (foil) tape to seal the seams and connections of ducts. After sealing the ducts in those spaces, wrap them in insulation to keep them from getting hot in the summer or cold in the winter. Next, look to seal any other ducts that you can access in the heated or cooled part of the house. See our See our Duct Sealing brochure (1.13MB) for more information. for more information.

Consider installing ENERGY STAR qualified heating and cooling equipment

If your HVAC equipment is more than 10 years old or not keeping your house comfortable, have it evaluated by a professional HVAC contractor. If it is not performing efficiently or needs upgrading, consider replacing it with a unit that has earned the ENERGY STAR. Depending on where you live, replacing your old heating and cooling equipment with ENERGY STAR qualified equipment can cut your annual energy bill by more than $115. But before you invest in a new HVAC system, make sure that you have addressed the big air leaks in your house and the duct system. Sometimes, these are the real sources of problems rather than your HVAC equipment.

Ask about Proper Installation of your new equipment

Replacing your old heating and cooling equipment with new, energy-efficient models is a great start. But to make sure that you get the best performance, the new equipment must be properly installed. In fact, improper installation can reduce system efficiency by up to 30 percent – costing you more on your utility bills and possibly shortening the equipment’s life. Learn more.

Building Envelope

(source: Center for Climate and Energy Solutions)
Quick Facts

  • Residential and commercial buildings account for almost 39 percent of total U.S. energy consumption and 38 percent of U.S. carbon dioxide (CO2) emissions.[1]
  • Space heating, cooling, and ventilation account for the largest amount of end-use energy consumption in both commercial and residential buildings. In the commercial sector they are responsible for 34 percent for energy used on site and 31 percent of primary energy use[2]. In the residential sector, space heating and cooling are responsible for 52 percent of energy used on site, and 39 percent of primary energy use.[3]
  • The building envelope – the interface between the interior of the building and the outdoor environment, including the walls, roof, and foundation – serves as a thermal barrier and plays an important role in determining the amount of energy necessary to maintain a comfortable indoor environment relative to the outside environment.


Nearly all of greenhouse gas (GHG) emissions from the residential and commercial sectors can be attributed to energy use in buildings (see Climate TechBook: Residential and Commercial Sectors Overview). Even so, existing technology and practices can be used to construct “net-zero energy” buildings ­ buildings that use design and efficiency measures to reduce energy needs dramatically and rely on renewable energy sources to meet remaining energy demand. The Energy Independence and Security Act of 2007 (EISA 2007) calls for all new commercial buildings to be net-zero energy by 2030. An integrated approach provides the best opportunity to achieve significant GHG reductions from the buildings sector, because many different building elements interact with one another to influence overall energy consumption (see Climate TechBook: Buildings Overview). However, certain key building elements can play a significant role in determining a building’s energy use and associated GHG emissions and merit a more in-depth consideration.

The building envelope is the interface between the interior of the building and the outdoor environment, including the walls, roof, and foundation. By acting as a thermal barrier, the building envelope plays an important role in regulating interior temperatures and helps determine the amount of energy required to maintain thermal comfort. Minimizing heat transfer through the building envelope is crucial for reducing the need for space heating and cooling. In cold climates, the building envelope can reduce the amount of energy required for heating; in hot climates, the building envelope can reduce the amount of energy required for cooling. A substantial part of “weatherization” includes improvements to the building envelope, and government weatherization programs often cite energy and energy bill savings as a primary rationale for these initiatives.


The building envelope can affect energy use and, consequently, GHG emissions in a variety of ways:

  • Design of the building envelope

The overall design can help determine the amount of lighting, heating, and cooling a building will require. Architects and engineers have developed innovative new ways to improve overall building design in order to maximize light and heat efficiency, for example through passive solar heating, which uses the sun’s heat to warm the building when it is cold without relying on any mechanical or electrical equipment.[4] Local climate is an important determinant for identifying the design features that will result in the greatest reductions of energy needs. These may include such things as south-facing windows in cool climates and shading to avoid summer sun in hot climates.[5]

  • Building envelope materials and product selection
  • Embodied energy

Embodied energy refers to the energy required to extract, manufacture, transport, install, and dispose of building materials, including those used in the building envelope. Efforts to reduce this energy use and associated emissions, for example through the substitution of bio-based products, can be made as part of a larger effort to reduce emissions from buildings.

  • Insulation and air sealing

Heat naturally flows from a warmer to a cooler space; insulation provides resistance to heat flow, thereby reducing the amount of energy needed to keep a building warm in the winter and cool in the summer. Insulation is frequently discussed in terms of its ability to resist heat flow, or its R-value. A variety of insulation options exist, including blanket, concrete block, insulating concrete forms, spray foam, rigid foam, and natural fiber insulation.

Adding insulation strategically will improve the efficiency of the building; however, it is only effective if the building is properly sealed. Sealing cracks and leaks prevents air flow and is crucial for effective building envelope insulation. Leaks can generally be sealed with caulk, spray foam, or weather stripping.[6]

  • Roofs

Roof design and materials can reduce the amount of air conditioning required in hot climates by increasing the amount of solar heat that is reflected, rather than absorbed, by the roof. For example, roofs that qualify for ENERGY STAR®[7] are estimated to reduce the demand for peak cooling by 10 to 15 percent.[8] Proper insulation is also important in attics and building cavities adjacent to the roof.

In addition, roofs also offer several opportunities for installing on-site generation systems. Solar photovoltaic (PV) systems can either be installed as a rooftop array on top of the building or a building-integrated photovoltaic system can be integrated into the building as roofing tiles or shingles (see also Climate TechBook: Solar Power).

  • Walls

Like roofs, the amount of energy lost or retained through walls is influenced by both design and materials. Design considerations affect the placement of windows and doors, the size and location of which can be optimized to reduce energy losses. Decisions regarding the appropriate material can be more complicated because the energy properties of the entire wall are affected by the design. Importantly, material selection and wall insulation can both affect the building’s thermal properties.

A building’s thermal mass – i.e., its ability to store heat – is determined in part by the building materials used. Thermal mass buildings absorb energy more slowly and then hold it longer, effectively reducing indoor temperature fluctuations and reducing overall heating and cooling requirements. Thermal mass materials include traditional materials, such as stone and adobe, and cutting edge products, such as those that incorporate phase change materials (PCMs). PCMs are solid at room temperature and liquefy as they absorb heat; the absorption and release of energy through PCMs helps to moderate building temperature throughout the day.

  • Windows, doors, and skylights

Collectively known as fenestration, windows, exterior doors, and skylights influence both the lighting and the HVAC requirements of a building. In addition to design considerations (the placement of windows and skylights affects the amount of available natural light), materials and installation can affect the amount of energy transmitted through the window, door, or skylight, as well as the amount of air leakage around the window components. New materials, coatings, and designs all have contributed to the improved energy efficiency of high-performing windows, doors, and buildings. Some of the advances in windows include: multiple glazing, the use of two or more panes of glass or other films for insulation, which can be further improved by filling the space between the panes with a low-conductivity gas, such as argon, and low-emissivity (low-e) coatings, which reduce the flow of infrared energy from the building to the environment.

In residential buildings, using optimum window design and glazing specification is estimated to reduce energy consumption from 10 to 50 percent below accepted practice in most climates; in commercial buildings, an estimated 10 to 40 percent reduction in lighting and HVAC costs is attainable through improved fenestration.[9]

  • Interactions with other building elements

The building envelope can affect the lighting, heating, and cooling needs of the building. These interactions are important to consider when retrofitting or weatherizing buildings to reduce their energy use in the most cost-effective manner. For example, with a new building it may be more cost-effective to choose a design with a more costly, high-performance building envelope that significantly reduces the need for heating and cooling with a smaller, less-costly HVAC system. For existing buildings, it may be more cost-effective to add insulation to a building than to install a more efficient heating system.

Environmental Benefit / Emission Reduction Potential

Improvements to the building envelope have the potential to reduce GHG emissions from new and existing buildings in the residential, commercial, and industrial sectors. The building envelope can significantly affect the amount of required lighting and HVAC, the two largest end uses of energy in both the residential and commercial sectors. Local climate influences the appropriateness and cost-effectiveness of many decisions pertaining to building envelope design and product selection.

Greater GHG emission reductions can be achieved through integrated approaches that consider the entire building as a whole. Significant improvements in energy efficiency are attainable and can reduce building-related emissions to very low levels or, when coupled with renewable energy sources, to zero.

In addition to the climate benefits, many building envelope improvements also result in a variety of benefits for consumers, including lower energy bills, as well as improved thermal comfort, moisture control, and noise control.


Improvements to the building envelope have the potential to be cost-effective for both new and existing buildings. From a climate perspective, improvements to the building envelope should be pursued because they reduce GHG emissions; from a consumer perspective, improvements to the building envelope should be pursued because they can result in both a more comfortable indoor environment and reduced energy costs. The ENERGY STAR® program provides estimates of cost savings associated with several building envelope elements, for example:

  • Windows

For a typical home, an ENERGY STAR® window will save $126 to $465 per year when replacing single-pane windows and $27 to $111 per year when replacing double-pane windows.[10]

  • Insulation and air sealing

By sealing air leaks and adding insulation from average values to recommended values, the average home in the northern United States can save 12 percent on its total utility bill (19 percent of heating and cooling costs) and the average home in the southern United States can save 11 percent on its total utility bill (20 percent of total costs).[11]

Energy audits can be conducted to identify the most cost-effective ways to improve energy efficiency in existing buildings. New buildings can be cost-effectively built to have lower energy needs, and the Commercial Building Initiative, a public-private collaboration, has a goal of having marketable net-zero commercial buildings beginning in 2025.[12] Importantly, these whole-building efforts include, but are not limited to, improvements to the building envelope.

Obstacles to Further Development or Deployment

In broad terms, the obstacles to improved building envelopes are the same as the obstacles faced by buildings broadly. These barriers include cost concerns, market barriers, public policy and planning barriers, and customer barriers. More narrowly, these obstacles pose different barriers to new and existing buildings, as well as to each of the different building envelope elements. The cost-effectiveness of certain building envelope improvements, such as improved insulation and sealing of air leaks, has not led to widespread implementation. Insulation retrofits, for example, would not only reduce GHG emissions, but they would also reduce energy consumption and consumer energy bills, improve air quality, and reap a variety of public health benefits.[13] These kinds of energy efficiency projects are part of the low-hanging fruit for reducing GHG emissions.

Policy Options to Help Promote Building Envelope Improvements

Like the obstacles to building envelope improvements, the available policy options fall into the same general categorization as buildings overall. Some policy and program interventions focus on improvements to a single building-envelope element, such as insulation. Tax incentives and other programs can change annually. A number of organizations track buildings-related policies; see below for a sample of useful references:

  • Standards and codes

Regulatory policies include mandatory and voluntary building codes passed by states and localities.

  • Financial incentives

Financial incentives include tax credits, rebates, low-interest loans, energy-efficient mortgages, and innovative financing, all of which address the barrier of first costs. Many utilities also offer individual incentive programs, because reducing demand, especially peak demand, can enhance the utility’s system-wide performance.

  • Weatherization Assistance Program – provides low-income families with weatherization services, including insulation, air sealing, and windows. Weatherization Assistance Program
  • Database of State Incentives for Renewables and Efficiency (DSIRE) – tracks federal and state incentives for renewable and energy efficiency programs, including summary maps and tables, as well as a searchable database.
  • Information and education

While many businesses and homeowners express interest in making energy-efficiency improvements for their own buildings and homes, they often do not know which products or services to ask for, who supplies them in their areas, or whether the actual energy savings will live up to claims. A variety of programs provide useful information on building envelope improvements and other energy efficiency measures.

  • ENERGY STAR® – a joint program of the U.S. Environmental Protection Agency (EPA) and DOE provides information on and standards for energy efficient products and practices.
  • Energy Savers – a government program that provides information on ways to save energy at home, while driving, and at work.
  • Lead-by-example programs

A variety of mechanisms are available to ensure that government agencies lead by example in the effort to build and manage more energy-efficient buildings and reduce GHG emissions.

  • Research and development (R&D)

R&D programs provide funding and support for advanced building materials and practices. Government funding is important because the fragmented and highly competitive market structure of the building sector and the small size of most building companies discourage private R&D, on both individual components and the interactive performance of components in whole buildings.

Tax Credits and Incentives

Residential Energy Tax Credits, Rebates, and Savings are searchable by state on The Department of Energy’s Savings Page.