Windham resident Khanh Ngo, a self-described “numbers guy” and owner of the computer repair business Maine Computer MD in North Windham, is passionate about green energy.

Since he was a kid, Ngo dreamed of owning his own home by the age of 30. But this couldn’t be just any home, Ngo, now 33, told his wife Tho Ngo, “since I’m into technology, I wanted the home to be as high-tech as possible based on our budget,” he said.

Now, Ngo and his wife are “living proof,” he says, that an energy-efficient home can be attainable for anyone, even on a limited budget. With Earth Day being observed April 22, it’s a timely lesson.

In 2012, the Ngos broke ground on their 1,587-square-foot, Cape Cod-style home in Windham, which uses some of the latest green technology. The home features a geothermal heating and cooling system, 24 solar panels on the roof and top-notch insulation that keeps the house draft-free.

Ngo said he consulted with Rocky Ackroyd at GreenSun, a solar panel installation and energy consulting company based in Windham, for advice regarding energy efficiency.

Since April 2013, when the family moved into their home on Orion Road, off Albion Road, Ngo has tracked their monthly electric bill. Comparing their numbers with the state’s average for heating oil and electricity costs, he has found that while the systems cost more up front, they have significant savings over time.

One of the Ngo family’s biggest investments was the geothermal heating and cooling system, which runs on electricity. Rather than using outdoor air like an air conditioner, the geothermal system pulls water from underground – where temperatures are relatively stable, despite the weather – to heat or cool the home.

The geothermal system cost $21,500, according to Ngo, approximately $8,000 more than a standard hot-air system. However, it cost the family about $1,100 annually to run, as opposed to the average heating cost for oil in Maine, which is roughly $3,000.

After four years, the savings from the geothermal system will offset the additional upfront cost for the system, and the family will save approximately $2,000 annually.

In September 2013, the Ngo family installed solar panels on their roof. The electricity generated by the panels goes into a “kilowatt bank account” with Central Maine Power, which is used to offset the costs of their electricity bill.

During the summer months, roughly from May to September, the Ngos pay nothing to Central Maine Power, thanks to their solar panels. Ngo said they save about $650 annually in electrical costs.

While solar energy is expensive to install, the Ngos have arranged a power-purchase agreement with Green Sun. Ackroyd said the Ngos will rent the panels for six years, after which they have the option of purchasing the panels for less than 50 percent of the original cost.

Ackroyd said he can only arrange one or two power-purchasing agreements each year, but that other companies in the area can provide similar arrangements.

While the state offers interest-free loans for Mainers investing in green technology, Ngo said he opted to include the costs of the technology in his monthly mortgage plan.

Ngo said embracing the technology was about more than just the numbers, it’s about concern for the environment, too.

The family has adopted other eco-friendly practices, such as gardening, keeping their own chickens for eggs, and preserving fish they catch in the summer for consumption in the winter.

“Global warming is a big deal,” Ngo said, “and I’m a big believer that we are the cause. If we can be one less of a factor, that might make a big difference.”

Tho Ngo, who works as a program manager at MaineHealth, said when she and her husband started researching energy-efficient solutions, “we didn’t know about this technology, and we were skeptical” about the actual cost savings.

After investing in the technology and seeing the results, Tho Ngo said she hopes people “will be more open-minded for information and make their own decisions.”

For the Ngos, the savings are great, but the comfort of the geothermal system is of the utmost importance, too.

The family leaves the thermostat at 70 degrees year-round, without worrying about excessive spending.

Designing an efficient home

Justin McIver, owner of Maine Eco Homes in Bridgton, makes his business of constructing energy-efficient homes in the Lakes Region.

McIver designs and builds everything from million-dollar homes – one of which went viral on the company’s Facebook page last week – to affordable cottages for a 55-plus living community in Bridgton on South High Street. The cottage-style homes run from $129,000 to $250,000, McIver said.

He said there are five major considerations to make when constructing an eco-friendly home. One is to build space-efficient designs that are easier to heat.

“Build only the space you need,” he said.

Second and third is to create a “passive solar-design” by installing as many windows as possible on the south side of the house, and ensure an air-tight exterior to the building (also known as the envelope) by using the best possible installation.

Fourth, McIver said, is reducing your electrical load by using LED lighting and Energy Star-compliant appliances.

And finally, achieve “net-zero” energy use by introducing an alternative energy source, like solar panels or wind power.

Incentives offered for efficiency projects

One of the most cost-effective solutions for homeowners looking to reduce their energy bill, according to Michael Stoddard, executive director at Efficiency Maine, is to have their home professionally air-sealed. Anyone who has done home improvements by caulking around their windows will be “familiar with the basic concept,” he said.

Contractors will find cracks and holes “you don’t know are there,” Stoddard said, because they’re “buried under a bit of installation, or in a corner of the attic.”

Efficiency Maine offers incentive programs for homeowners who undertake efficiency projects, Stoddard said, including a $400 rebate for a basic air-sealing job.

“If you decide to go further” in weatherizing your home, Stoddard said, introducing new installation into the walls of your home “will make your home way more comfortable and reduce energy bills for decades.”

For more information on incentives, and to search for energy-efficient contractors in your region, visit the Efficiency Maine website: http://www.efficiencymaine.com/

Khanh and Tho Ngo hold their 2-year-old daughter, Elsa Ngo, outside their Windham home. The family built their home in 2012 using energy-efficient technologies, and are now reaping the benefits, they said.