Whether you’re building the home of your dreams or looking for an existing unit, there’s a lot of data involved in finding the right environmentally friendly dwelling. Here’s a breakdown of the different certification systems for energy-efficient homes.

RESNET
The Residential Energy Services Network is a not-for-profit corporation that develops industry-wide standards and rules for energy efficiency ratings and certification systems for buildings. In addition to overseeing the HERS index (see below), RESNET certifies contractors of all types, including builders, roofing and siding professionals, and remodeling contractors.

HERS index
The Home Energy Rating System is an index measuring a home’s energy efficiency. An average home built to current industry standards for energy efficiency will have an index of 100. A lower score indicates higher levels of efficiency (for example, a home with a score of 70 is using 30 percent less energy than the average home). The opposite is true with homes that score higher than 100. This index is overseen by RESNET.

LEED
The United States Green Building Council is the agency that bestows Leadership in Energy and Environmental Design certifications on environmentally friendly buildings and projects. The highest certification a building can earn is “LEED platinum.” Projects earn points based on numerous categories such as indoor air quality and water efficiency. More points add up to a higher certification level.

Energy Star
The Energy Star program is overseen by the U.S. Environmental Protection Agency. Products such as refrigerators, light bulbs, and furnaces can earn Energy Star certifications. Separately, homes can be Energy Star–certified through an independent inspection.

Indoor airPLUS:
This program is also administered by the EPA. Homes that go above and beyond the Energy Star requirements by incorporating additional features to combat moisture, mold, pests, and pollutants can earn this label.

National Green Building Certification
Overseen by the National Association of Home Builders, this program helps residential building professionals develop and build sustainable projects. Buildings can earn bronze, silver, gold, or emerald certifications. At the Emerald level — which is the highest certification a project can earn — a building “must incorporate energy savings of 60 percent or more.”

Radon
A colorless, odorless gas that can seep into your home from the ground, radon is often referred to as the second most common cause of lung cancer behind smoking.
What to look for: Basements or any area with protrusions into the ground offer entry points for radon. The Environmental Protection Agency publishes a map of high-prevalence areas. A radon test can determine if high levels are present.

Asbestos
A fibrous material once popular as fire-resistant insulation, asbestos was banned in 1985. However, it’s often found in the building materials, floor tiles, roof coverings, and siding of older. If disturbed or damaged, it can enter the air and cause severe illness.
What to look for: Homes built prior to 1985 are at risk of having asbestos in their construction materials. Home owners should be careful when remodeling because disturbing insulation and other materials may cause the asbestos to become airborne.

Lead
This toxic metal used in home products for decades can contribute to several health problems, especially among children. Exposure can occur from deteriorating lead-based paint, pipes, or lead-contaminated dust or soil.
What to look for: Homes built prior to 1978 may have lead present. Look for peeling paint and check old pipes. To get a HUD-insured loan, buyers must show a certificate that their older home is lead-safe.

Other hazardous products
Stockpiles of hazardous household items — such as paint solvents, pesticides, fertilizers, or motor oils — can create a dangerous situation if not properly stored. They can easily spark fires and can cause illness or even death if ingested, even in small amounts.
What to look for: Check all the corners, crawl spaces, garages, or garden sheds in the home. If these products are found, make sure you ask for their removal and get a disposal certificate prior to closing.

Groundwater contamination
When hazardous chemicals are disposed of improperly, they can seep through the soil and enter water supplies. A leaking underground oil tank or septic system can contribute to this.
What to look for: Homes near light industrial areas or facilities may be at risk, as are areas once used for industry that are now residential.

Some items should always be examined.

Structure
The home’s “skeleton” should be able to stand up to weather, gravity, and the earth that surrounds it. Structural components include items such as the foundation and the framing.

Exterior
The inspector should look at sidewalks, driveways, steps, windows, doors, siding, trim, and surface drainage. They should also examine any attached porches, decks, and balconies.

Roofing
A good inspector will provide very important information about your roof, including its age, roof draining systems, buckled shingles, and loose gutters and downspouts. They should also inform you of the condition of any skylights and chimneys as well as the potential for pooling water.

Plumbing
They should thoroughly examine the water supply and drainage systems, water heating equipment, and fuel storage systems. Drainage pumps and sump pumps also fall under this category. Poor water pressure, banging pipes, rust spots, or corrosion can indicate larger problems.

Electrical
You should be informed of the condition of service entrance wires, service panels, breakers and fuses, and disconnects. Also take note of the number of outlets in each room.

Heating and air conditioning
The home’s vents, flues, and chimneys should be inspected. The inspector should be able to tell you the water heater’s age, its energy rating, and whether the size is adequate for the house. They should also describe and inspect all the central air and through-wall cooling equipment.

Interiors
Your inspector should take a close look at walls, ceilings and floors; steps, stairways, and railings; countertops and cabinets; and garage systems. These areas can reveal leaks, insect damage, rot, construction defects, and more.

Ventilation/insulation
Inspectors should check for adequate insulation and ventilation in the attic and in unfinished areas such as crawl spaces. Insulation should be appropriate for the climate. Without proper ventilation, excess moisture can lead to mold and water damage.

Fireplaces
They’re charming, but fireplaces can be dangerous if they’re not properly installed. Inspectors should examine the vent and flue, and describe solid fuel-burning appliances.

Do you belong to a professional association?
There are many associations for home inspectors, but some groups confer questionable credentials or certifications in return for nothing more than a fee. Make sure the association your home inspector names is a reputable, nonprofit trade organization.

Will your report meet all state requirements?
Also, make sure the organization complies with a well-recognized standard of practice and code of ethics, such as those adopted by the American Society of Home Inspectors or the National Association of Home Inspectors.

How experienced are you?
Ask inspectors how long they’ve been working in the field and how many inspections they’ve completed. Also ask for customer referrals. New inspectors may be highly qualified, but they should describe their training and indicate whether they work with a more experienced partner.

How do you keep your expertise up to date?
Inspectors’ commitment to continuing training is a good measure of their professionalism and service. Advanced knowledge is especially important with older homes or those with unique elements requiring additional or updated training.

Do you focus on residential inspection?
Home inspection is very different from inspecting commercial buildings or a construction site. Ask whether the inspector has experience with your type of property or feature. The inspector should be able to provide sample inspection reports for a similar property. If they recommend further evaluation from outside contractors on multiple issues, it may indicate they’re not comfortable with their own knowledge level.

Do you offer to do repairs or improvements?
Some state laws and trade associations allow the inspector to provide repair work on problems uncovered during the inspection. However, other states and associations forbid it as a conflict of interest.

How long will the inspection take?
On average, an inspector working alone inspects a typical single-family house in two to three hours; anything less may not be thorough.

How much?
Costs range from $300 to $500 but can vary dramatically depending on your region, the size and age of the house, and the scope of services. Be wary of deals that seem too good to be true.

Will I be able to attend the inspection?
The answer should be yes. A home inspection is a valuable educational opportunity for the buyer and a refusal should raise a red flag.

Before you purchase a condo, you should have an attorney review property documents for you. However, you should contact the board yourself ahead of time. You’ll learn how responsive and organized its members are and be alerted to potential problems.

How many units are owner-occupied?
Generally, the higher the percentage of owner-occupied units, the easier the condo will be to resell.

What covenants, bylaws, and restrictions govern the property?
Carefully read the bylaws to determine if you can abide by them. Also, find out if there are grandfather provisions that allow current owners more rights than you would have as a new owner, such as the ability to rent out your unit.

How much does the association keep in reserve?
Ask how the money is being invested.

Are association assessments keeping pace with the annual rate of inflation?
Smart boards raise assessments a reasonable percentage each year to build reserves for funding future repairs.

What does the assessment cover?
Ask specifically about common-area maintenance, recreational facilities, trash collection, and snow removal (if applicable).

What special assessments have been mandated in the past five years, and how much of that was the responsibility of individual owners?
Some special assessments are unavoidable. But repeated, expensive assessments could be a red flag about building conditions or fiscal policy.

What’s the turnover rate?
This will tell you if residents are generally happy with the building.

Is the condo building in litigation?
Obviously, this is never a good sign. If the builders or owners are involved in a lawsuit, reserves can be depleted quickly to pay legal fees.

What other projects has the developer built?
Try to visit one, and ask residents about their perceptions. Also, request an engineer’s report if the building has been converted from another use.

Are multiple associations involved in the property?
In very large developments, umbrella associations also may require separate assessments.

Condominiums, townhomes, and properties located within a homeowner association offer certain perks, but it’s important to consider them in your decision process.

How much storage is available?
Some properties include storage lockers, but there may not be attics or basements to hold extra belongings.

How’s the outdoor space?
Your yard may be smaller than you’d find in a traditional single-family home, so if you like to garden or entertain outdoors, this may not be a good fit. But if you dread yard work, it may be the perfect option.

Are amenities important?
Many properties offer swimming pools, fitness centers, and other facilities that would cost much more in a single-family setting.

Who handles maintenance and security?
Property managers often hire professionals to care for common areas and perform in-unit repairs. Keyed entries and doormen may regulate access to your home when you’re not there (good news if you travel).

Are there required reserve funds and association fees? How much are they?
Although fees generally help pay for amenities and provide savings for future repairs, the HOA or condo board determines these fees, and you’ll have to pay them even if you’re not in favor of the improvements.

What are the association rules?
Although you have a vote on future changes, association rules can dictate how you use your property. Some condos prohibit home-based businesses; others prohibit pets or don’t allow owners to rent out their units. Read the covenants, restrictions, and bylaws carefully before you make an offer.

What’s the average vacancy rate?
It’s never too early to be thinking about resale. The ease of selling your unit may depend on what else is for sale in your building, since units are similar.

How many units are owned by investors?
Some lenders require a certain percentage of the building to be owner-occupied and may not be able to offer you financing if the ratio is too low.

Can I meet other residents before making an offer?
You will share space and decision-making duties with your neighbors when part of a homeowner association, so it’s important to make sure you can work together. If possible, try to meet your closest prospective neighbors before you decide on a place.

Where you live should reflect your lifestyle. These questions will help you find the best community for you.

Is it close to my favorite spots?
Make a list of activities you engage in and stores you visit frequently. See how far you would have to travel from each neighborhood you’re considering to engage in your most common activities.

Is it safe?
Contact the police department to obtain neighborhood crime statistics. Consider not only the number of crimes but also the type and trend. (Is crime going up or down?). Pay attention to see where in the neighborhood the crime is happening.

Is it economically stable?

Check with your local economic development office to see if household income and property values in the neighborhood are stable or rising. What is the ratio of owner-occupied homes to rentals? Apartments don’t necessarily diminish value, but they indicate a more transient population. Are there vacant businesses or homes that have been on the market for months? Check news sources to find out if new development is planned.

Is it a good investment?
Ask a local REALTOR® about price appreciation in the neighborhood. Although past performance is no guarantee of future results, this information may give you a sense of how a home’s value might grow. A REALTOR ® also may be able to tell you about planned developments or other changes coming to the neighborhood — such as a new school or highway — that might affect its value.

Do I like what I see?
Once you’ve narrowed your focus to two or three neighborhoods, go and get a feel for what it might be like to live there. Take notes: Are homes tidy and well maintained? Are streets bustling or quiet? How does it feel? Pick a pleasant day if you can, and chat with people working or playing outside.

What’s the school district like?
This is especially important if you have children, but it also can affect resale value. The local school district can probably provide information on test scores, class size, the percentage of students who attend college, and special enrichment programs. If you have school-age children, visit schools in neighborhoods you’re considering.