YARMOUTH — Weeks ago, builder Josh Wojcik’s crew was tearing the roof off a 1973 ranch house that they’re converting into a high-efficiency home. A passing critic pulled his truck to the curb and leaned out the window.

“He said, ‘You’re doing too much!’” said Wojcik.

The perception of overkill is a common challenge for builders of high-efficiency houses that replace traditional heating systems with low-energy heating units. They say the extra upfront investment comes back in energy savings and a reduced carbon footprint.

Recently, Wojcik has placed a bet that those types of homes aren’t just for the high-minded and well-heeled anymore.

The latest projects from Wojcik’s Upright Properties, and other contractors focused on energy efficiency, are testing whether super-insulated, low-energy homes could be more than a niche business, competing for buyers against homes built to more traditional standards.

“This is the sort of new frontier for us is to see if there’s interest in actually just buying these houses flat-out,” said Wojcik. “We know the custom home [business] is there.”

With the remodeling still underway at the Yarmouth home, Wojcik said his company is in talks with an interested buyer — at an asking price of about $400,000, which he said is in line with homes in the area.

The median price for a Yarmouth home in 2012 was $298,500.

His hope is that high-efficiency homes like the Yarmouth structure — where the basement still smells of the oil furnace taken out earlier this year — will reach deep into the mid-range housing market.

Bangor-based building retrofitter House Revivers is doing the same. The company plans to complete the first of its six Bangor EcoHomes houses between Fern and Pearl streets by the end of the month, with an open house set for July 26.

“We wanted to build a model home to show some of the options that are available,” said David Kelly, Bangor EcoHomes’ project manager. “Once you have one house built to that [high-efficiency] standard, it sets a new precedent in that area.”

Kelly said the company hopes to sell the first home, built without a defined buyer, for about $255,000. The median value for a home in Bangor was $147,500 in 2012.

Construction on the project’s second house — custom built for a customer — will start in August.

Global conference

Part of the challenge in marketing low-energy homes is awareness among buyers and builders about the techniques and technology for high-efficiency building, which will get a boost in Maine this fall.

The North American Passive House Network, one of a few passive home building associations, recently announced it will host its second annual conference in Portland in September. The conference will bring international designers to speak over two days and will include visits to Maine projects.

While most high-efficiency builders said the requirements for full certification as a “passive house” heap additional costs onto a project, they anticipate the conference will boost the industry across the region.

“Even if we’re not building to that standard, we’ll benefit from it,” Wojcik said. “It will raise the dialogue [about high-efficiency homes] in the industry.”

Statewide numbers for high-efficiency homes aren’t readily available as the projects don’t require any special certification, but architecture firm Kaplan Thompson’s entry into that market through its BrightBuilt Homes provides additional metrics.

Parlin Meyer, BrightBuilt’s director, said since starting last June the company’s new division has completed 11 high-efficiency projects, six of them modular construction. It has another 17 under contract in various states.

Matt O’Malia, a partner and founder of the high-efficiency building firm G•O Logic, said the September conference will bring more attention to that growth in Maine and across the region.

“We’re really in a place where super-insulation is a benefit and I think the Northeast passive house is a hand-and-glove fit,” O’Malia said. “The kind of expertise that Maine has developed in passive house construction … is something we can export to the rest of the country.”

O’Malia said G•O Logic, which built the first passive certified house in Maine and Michigan and recently completed the Belfast Cohousing & Ecovillage, has 36 high-efficiency projects under its belt.

Most of those projects target what he said is a balance between cost and efficiency. At least five meet the passive standard, which needs to have specific design elements and can mean a reduction in energy use for heating of up to 90 percent.

And making the case to buyers has gotten easier in recent years, O’Malia said.

His company’s pitch states building a home to the passive standard uses 10 percent of the energy a typical home uses for heating and adds about 7 percent to the overall building cost, subtracting the cost of a traditional heating system.

For a 1,500-square-foot home built to code, G•O Logic estimates the savings at $1,400 per year.

The cost side of that equation is affected by better access to building supplies for high-efficiency units and declining costs of equipment that’s not needed for traditional homes, like energy recovery ventilators that heat or cool incoming fresh air next to the hotter or cooler air leaving the home.

“Since 2009, our ability to get materials and have a conversation about passive homes with the broader community has increased [significantly],” O’Malia said. “We’re seeing a huge change and it’s been a short period of time.”

But challenges remain, particularly in getting appraisals that factor in the value of a home’s energy savings.

“We had bank financing for the first house and it was tough to get that appraisal right so we could start building,” said David Kelly of Bangor EcoHomes.

Builders said part of the solution is getting homes sold to establish some precedent for high-efficiency home sales, but the issue is getting attention nationally as well.

Last year, the national Appraisal Institute issued a form outlining how appraisers should value certain efficiency characteristics of a home and a proposal to factor the value of a home’s energy efficiency into the mortgage value is part of a bill before Congress as part of the Energy Savings and Industrial Competitiveness Act of 2014.

Without those changes, high-efficiency builders said there are other trends in their favor, including rising energy costs, an improving housing market and costs for high-efficiency building becoming less expensive and more available, they think there’s room for that industry to grow.

“I think we have more certified passive houses and more near-passive houses in the state than most,” said Kelly. “It’s exciting to see that it’s blossoming in the state.”