Here’s How You Know You’re Buying an Energy-Efficient House

This story is part of Home Tips, CNET’s collection of practical advice for getting the most out of your home, inside and out.

Buying a house is never a minor decision, and it’s even more complicated now by increasing interest rates and inflation. So while prospective homeowners weigh factors like cost, square footage and proximity to parks and schools, they should also consider how a house can save them money after the purchase.

The average monthly utility bill in the US was about $117 in 2020. It’s likely more expensive now. Putting just $10 in electricity savings toward your mortgage every month could save you thousands over the lifetime of your loan. While there are plenty of ways to save energy in any home, like unplugging appliances, turning off lights and weather stripping windows and doors, buying an energy-efficient home in the first place makes all of that much easier.

But it’s not always easy to learn if a house is energy efficient before actually moving in. Since you can’t do a trial run before purchasing a house, you can get an idea of its energy efficiency beforehand with a few of the tips listed below. (And if you’re looking for ways to make your house more energy efficient, check out CNET’s advice on saving money and energy with smart devices, appliances and air conditioning to help lower your utility bills.) 

Read more: Best Smart Thermostats for 2022 

Find a Green Realtor

Before you start looking for homes, find someone who’s trained to find you an energy-efficient one, and make it an explicit part of your search. A few different organizations offer green certifications for real estate agents who are trained in energy efficiency. They also understand other environmental concerns, such as mold, asbestos and lead. 

Before you start your search, consider the energy efficiency concerns of your future home’s location. Will you be able to easily walk or bike to parks, grocery stores or restaurants? Once you’ve squared away where you’re looking and who’s helping you look, turn your attention to the house itself.

Solar panels

One obvious way to find a new house that uses as little energy from the grid as possible is to find one that generates its own. If you’re looking to buy a house with solar panels, make sure you understand your net metering program and if the previous owner bought, leased or entered into a power purchase agreement. Assuming a lease or PPA can be tricky and you’ll save the most money if you own them outright. Be sure to negotiate that and be prepared to pay a premium. (According to Zillow, solar panels increased a home’s resale value by 4% in 2019.)

You should also understand how much electricity the solar panels typically produce and how long is left on their warranty. While solar panels can last beyond the warranty, they do produce less electricity with time.

Smart devices

Smart devices can save money by automating energy saving practices and giving you more control over your energy use. Connecting your home to smart devices can let you turn down the furnace or shut off the lights when you forget to before leaving home.

Smart thermostats, which allow you to set a heating or cooling schedule and remotely access them, can save up to 8% on energy bills each year, Energy Star estimates. 

There are plenty of smart thermostats to choose from, including a whole slate of budget options. 

Read more: Make the Most of Your Smart Thermostat to Save Money and Energy Now

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The Amazon Smart Thermostat is the least expensive smart thermostat we’ve tested — and it’s also our favorite. 


Chris Monroe/CNET

Energy efficient appliances

If you’re looking at a house that comes with appliances, check to see if they are Energy Star certified. Energy Star is a program run by the US Department of Energy, and identifies which appliances meet certain efficiency standards.

To achieve Energy Star certification, televisions need to use about 50% less energy than their non-certified counterparts when they’re turned off. Light bulbs need to use two thirds less. Refrigerators need to be 15% more efficient than the federal efficiency standard. Energy Star certifies dozens of product categories.

Beyond certification, energy efficient alternatives to common appliances can cut down energy usage. A heat pump is more efficient than an air conditioner and furnace. Tankless water heaters can be 24% to 34% more efficient, depending on your water usage, according to the Department of Energy.

Read more: Storage Tank Water Heaters vs. Tankless Water Heaters

Water harvesting systems

There are two types of water-harvesting systems that can green up a home: rain harvesting and gray-water harvesting.

Rainwater-harvesting systems can be as simple as plastic barrels attached to the gutter system, or as complex as underground storage tanks complete with filters to sanitize the water. The type of gathering system you want in your future home depends on your needs.

If you just want to capture rainwater for your garden during dry times, then a barrel system will do the trick. On the other hand, if you want to collect enough water to supply your entire household, multiple storage tanks and plumbing to the home would be a better choice.

Read more: How to install a rain barrel to save money and help the planet

Gray-water harvesting systems reuse water from sources such as the kitchen sink and the bathtub. Before buying a home with a gray-water system, be sure to ask exactly how the water is reused. Some systems will collect the water from sinks, showers and tubs and store it for use in toilets or sprinkler systems. More advanced systems will filter the water so that it can be reused for drinking, cooking and bathing.

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This house has slanted roofs, which direct water to a water filtering and storage system.


Screenshot by Martin LaMonica/CNET

While you’ll likely lower your water bill, you may not eliminate it. Some towns require residents to pay for city-supplied water, whether they use it or not.

Insulation, windows, shade and more

Ask your home inspector to check the house’s shell. Things like insulation and snug windows, while not as flashy as solar panels or new appliances, can save you a lot of money on heating and cooling in the long run. The Environmental Protection Agency estimates that insulating and sealing a house can save 11% to 15% of a family’s heating and cooling cost or more in certain parts of the country.

The EPA says heat gained or lost through windows accounts for 25% to 35% of residential heating or cooling costs. Properly installed, energy efficient windows can save you big, then. Look for windows certified by Energy Star and rated by the National Fenestration Rating Council.

Also, consider the house’s roof color. Lighter roofs, sometimes called cool roofs, reflect more heat, saving you money on cooling in the summer.

Landscaping can be an energy saving tool, too. Deciduous trees can block the hot afternoon sun when they’re full of leaves in the summer, helping out your air conditioner. Come winter, the leaves will drop and let the afternoon sun warm your house, taking some pressure off your heating.

Green building certification

While you should consider these individual factors, in some cases, houses carry an energy-efficiency certification that covers several of the previously mentioned elements.

Besides appliances and windows, Energy Star certifies whole homes as energy efficient. The U.S Green Building Council runs the Leadership in Energy and Environmental Design certification for residential buildings. Homes can also be certified by the National Green Building Standard for energy efficiency and other environmental concerns. Each of these programs have their own certification criteria and scoring system, so even certified buildings might be improved.

Certification can take into account many of the measures discussed above. It can also take into account homes built with reclaimed materials or landscaped in an environmentally friendly way.

Energy-efficient mortgages

If your home search doesn’t turn up the perfectly energy-efficient home, don’t worry. There are tools to bring your home up to your standards. Energy-efficient mortgages allow you to lump the cost of energy efficiency upgrades into a loan for a new home or a refinance. This can save money by eliminating the origination and processing fees for a second loan and securing a lower interest rate for the home improvement portion of the loan.

An energy-efficient mortgage can be put toward many of the energy saving practices named above: insulation, solar panels, new windows and doors, energy efficient appliances and more. If you’re buying an inefficient home, you can start improving it from the very beginning.

If you’ve already bought your house or rent an apartment, read about the steps you can take to improve efficiency right now. Here are seven steps you can take right now to save some energy and money.