Heat of the Moment

Time and technology are changing. What’s the best heat for your house?

Stack of firewood - wooden abstract background.

The numbers are dropping fast, but roughly seven in 10 Maine homes still rely on oil as the primary heating fuel. So the recent sharp drop in wholesale petroleum prices has many homeowners wondering whether it’s worthwhile to convert from heating oil or kerosene to other fuels.

There may be a sense of relief now, but savvy Mainers know that while oil is low today, the global market is very volatile. They’ve been stung before, when prices spiked with little warning.

But which option is best? And beyond price, which alternatives are better for the environment and for fighting climate change? Which can help Maine cut its reliance on imported energy?

It’s a complicated decision. And it’s not just a decision for today. A heating option that seems less expensive in the short run can turn out to be very costly over time, if the heating system is inefficient and/or the price of fuel rises more than expected. And conversely, a heating system with a higher up-front price tag can produce lower and more stable heating costs in the long term. When financed, some heating systems–such as solar paired with heat pumps–offer the ability for monthly payments to equal the cost savings that you would otherwise be paying for less efficient—and non-renewable—heating options. And of course, cost is not the only consideration. Some heating options have a greater impact on the environment and on climate change than others. For many people, those concerns are just as important as the monetary cost.

Complicating matters further is that every home is different, and so is every heating system. Steve Konstantino, owner of Performance Building Supply in Portland, has been working with high performance building products and systems for most of his career. He recommends that homeowners have an energy audit and “energy model” performed to get an accurate understanding of the heating needs of their particular house before installing a new heating system. A simple calculation based on square footage is not adequate and can be misleading. “Determining the heat needs of a house should take into consideration the thermal performance of the house, including the level of insulation and how tightly the house is air sealed,” said Konstantino. “A skilled energy auditor can develop an accurate ‘energy model’ to determine the peak BTU load, the highest heating capacity that your house will need on the coldest hour of the year. Once you know this, then you can choose a correctly- sized heating system.”

heating cost graph

Pat Coon of Spark Applied Efficiency concurs with Steve. A solar electrician by trade, Coon has co-founded several renewable energy companies in his career including ReVision Energy, ReVision Heat, Interphase Energy and now Spark. Coon believes that most Maine homes are outfitted with heating systems that are too big for their needs and result in wasted fuel. “Most boilers are sized 50% bigger than they need to be and it leads to inefficiency,” said Coon. “Oversized boilers ‘short cycle,’ meaning they run for short periods of time and shut off. And because boilers run most efficiently after five minutes, a boiler that turns on and off in less than five minutes is wasting energy.”

To help sort through these issues, we’ve put together a primer covering the top heating choices for Maine and comparing them in terms of costs and impacts. Use it as a general guide, a starting point to explore the details of each option.

Whatever you pick, remember that less is more. The less heat you need, the more money you save. That means reduce your heating load first. Seal cracks around foundations, windows and doors. Insulate basements and upgrade insulation in attics. Not sure where to start? Get an energy audit.

“Consumers need to consider measuring and lowering their energy load prior to making fuel and system upgrades,” says Konstantino. “The interesting thing is that it is almost never approached this way.”

Patrick Woodcock, Director of the Governor’s Energy Office, sees the current low oil prices as an opportunity for Mainers. “Heating oil prices this low are freeing up dollars that Maine households can use to invest in energy efficiency and heating system upgrades. When prices rise again, those investments will pay dividends. Now is the time to plan ahead.”

For advice on weatherization, heating system options, financing and rebates, check the Efficiency Maine website. Also available there are calculators to compare heating fuel costs and get a baseline of your home’s energy efficiency.


Heating oil is imported to Maine, a large share of it from overseas via Canada, where it’s refined at the Irving Oil refinery in Saint John, New Brunswick. Burning oil is a leading contributor to climate change, although new ultra-low sulfur blends are an improvement. While heating oil isn’t the biggest culprit in emitting the heat-trapping gas—burning coal in power plants is the worst offender—it continues to be a key contributor in Maine.

But love it or hate it, heating oil will remain a central way for Mainers to warm their homes for the foreseeable future. With wholesale prices recently hovering at a six-year low of $42 per barrel and retail costs as low as $1.74 per gallon in Greater Portland during August, 2015, the incentive for many homeowners to switch is on the back burner.

That trend is being noticed by Dan Vaillancourt, the president of Daigle Oil in Fort Kent. Daigle is currently experiencing growth in residential oil boiler installations.

“The biggest factors are the current fuel costs and the fact that the relative installation cost is significantly lower than (an alternative) central heating system,” Vaillancourt says.

A modern oil boiler can save money and create less air pollution when compared to boilers of yesteryear. New Energy Star®-rated oil boilers are running above 87 percent efficiency, which is a great improvement over the 60-70 percent efficient dinosaurs many Maine homes have in the basement.

Not ready to buy a new boiler? Thomas Tutor, an energy adviser at ReVision Heat in Portland, says an easy way to reduce oil usage is to optimize the existing boiler. This includes regular cleanings, reducing the nozzle size, insulating pipes and modulating the aquastat, which controls water temperature.

If the boiler is functioning well, consider removing the domestic hot water system and opt for a heat pump water heater. This reduces the amount of oil burned in the warmer months. A heat pump hot water heater runs at a fraction of the cost of an electric domestic hot water system, and it currently qualifies for a $500 rebate from Efficiency Maine.



A biofuel delivery truck in Portland. Biofuels can be used interchangeably with standard oil and reduce air emissions significantly when compared to heating oil alone. They are made from a blend of petroleum and either vegetable oil or recycled cooking oil. PHOTO: COURTESY MAINE BIOFUELS

For oil heat customers who want or need to stick with petroleum, but would like to reduce the impact on air quality, bio-fuels are a growing option. Biofuels, sometimes referred to as biodiesel and as bioheat when used for warming homes, are a blend of petroleum and either virgin vegetable oil or recycled cooking oil. The most common virgin feedstock is soybean, grown in the Midwest. Even a small blend of bio can help lower air emissions and result in a cleaner-burning boiler or furnace.

Biofuels are blended at various ratios. The most common offered by Maine oil dealers is called B5 or Bio5, which is 5 percent biofuel and 95 percent petroleum. Blend ratios can go up to 20 percent—B20—without making major modifications to fuel lines and pumps in the boiler or furnace. Several oil dealers in Maine, including Maine Biofuel, Harvest Energy and M.W. Sewall, offer biofuels, typically made from virgin feedstock. Prices vary, but generally track with conventional oil.

At least one dealer has turned bioheat into an indigenous resource. Maine Biofuels, a renewable energy company in Portland, produces Bio20 made from recycled cooking oil gathered from around New England.

“Bio20 is a blend of petroleum heating oil and biodiesel, and it’s a drop-in replacement to heating oil, meaning you don’t have to do anything to your furnace,” said Alex Pine, director of Outreach and Technology at the company. “It’s a great fuel for heating, because at the 20 percent level, when blended with ultra-low sulfur heating oil, you can actually match or beat the emissions of natural gas, without having to invest in new heating equipment.”

That makes biofuels a good option for many oil heat customers who are not ready to make a heating system switch, according to Lee Landry, a managing partner at ReVision Heat. “Some of the people we work with can’t afford to replace their heating system and we recommend switching to Bio20 as a zero cost upgrade that reduces carbon and improves efficiency at the same fuel cost,” he says.



A propane tank at a home in Buxton. PHOTO: JUSTIN ROMEO

Primarily a byproduct of natural gas refining, propane is a very versatile fuel. In Maine propane is typically found in rural areas where it powers kitchen stoves, dryers, gas fireplaces and stand-by generators. Typically running at 10-15 percent higher combustion efficiencies than oil, propane boilers rarely need cleaning and don’t require a standard chimney.

Propane is also a cleaner-burning fuel than conventional oil, emitting less carbon dioxide into the atmosphere. Many of the optimization strategies for oil boilers are also available to propane users. Propane can also fire direct-vent wall heaters, such as those made by Rinnai, which can be an afford- able alternative to a central heating system for some homes.

But propane has several downsides. The price is often volatile and expensive and in recent years Maine experienced a shortage of the fuel. Next to electric resistance heat, it’s typically the most costly heating fuel in Maine. And the market for propane is less transparent and less competitive than heating oil. Dealers will only fill their own tanks, so once a homeowner hooks up with a propane supplier, it’s not practical to shop around for a better deal.

And propane’s certainly not a local fuel. Most propane comes into Maine by rail from Canada and the western United States. Some arrives by truck after being offloaded in Newington, N.H.


More than half the homes in America are heated with natural gas. It’s a relatively clean-burning fuel and plentiful now in the Northeast, thanks to shale gas deposits in New York and Pennsylvania. But the network of pipelines that supplies it has been slow to branch out in Maine. That’s changing now, as competition heats up between natural gas and oil heat.

For example, Summit Natural Gas has been expanding rapidly in the suburbs north of Portland and the Kennebec Valley, although low oil prices and fewer-than-expected customers recently forced it to cut back plans. In Falmouth, Cumberland and Yarmouth, Summit has been offering a 15 percent below oil price guarantee, up to the first $750, for the first 1,000 customers who sign on. Propane customers are being offered a $375 coupon to switch. Along with the incentives already offered by Efficiency Maine and Summit, it could reduce transition costs by over $4,000.

In southern Maine, Unitil’s customer conversion rate is growing at a steady 3 percent a year, almost triple the national average, and 230 customers took a $1,000 rebate offered through Efficiency Maine over the last 12 months.

That said, thousands of homes in rural Maine are just too far from the backbone distribution lines to see natural gas in the near future. Piping gas there just isn’t economical.

And although it offers lower carbon dioxide emissions than conventional oil, natural gas is not a completely clean fuel. Production emits methane, a powerful greenhouse gas. And hydraulic fracturing, the process of injecting water and chemicals into shale deposits to gather gas, is being blamed for well pollution and earthquakes. At the same time, environmental groups worry that expanding natural supply gas pipelines in New England, a process under way to help serve power plants that use gas to make electricity, will stifle the development of wind, solar and other renewable generation sources.


Electric resistance heat, from baseboards and space heaters, is convenient and cheap to install. But it can also be the most expensive way to heat a home, so it’s a better choice for taking the chill off the TV room at night, rather than trying to warm an entire house.

Electric heat has also gotten greener in Maine. The de- regulation of Maine’s electricity markets in 2000, coupled with the shale gas boom, resulted in a transition from coal and nuclear-fired electricity plants to natural gas. Gas now generates roughly 50 percent of New England’s electricity.

At the same time, Maine has led the region in the use of renewables for electric generation.

According to the Maine Governor’s Energy Office, Maine has the highest per-capita generation of electricity from bio-mass in the United States. It produces more hydro power per capita than any other state east of the Mississippi River, and it’s also a regional leader in wind power. So heating with electricity in Maine has a lower carbon impact, compared to many other states.

Home customers who heat with electricity can lower their carbon footprint further by choosing a “green” power supply, such as Maine Green Power. Overseen by the Maine Public Utilities Commission, it purchases supply from renewable sources in Maine, currently from hydro, wind power and wood waste. When customers buy blocks of the supply (approximately $100/year for an average home), it has the effect of offsetting conventional power generation.


shutterstock_88135561The advantages of air-source heat pumps are clear for Mainers: now there’s a form of electric heat with a low cost similar to natural gas or wood, without the labor of hauling and stacking. Recent technology gains have heat pumps working down to minus 10 degrees, although at lower efficiencies. In the summer, heat pumps function as high-efficiency air conditioners.

“Maine is definitely setting the bar on the highest efficiency heat pump installs designed for cold climates,” according to Dana Fischer, residential program manager at Efficiency Maine. “Three hundred to 600 units are being installed every month from Kittery to Fort Kent. Because of the high volume and competition between installers, the cost of high quality installations on the best equipment is significantly lower than in other states.”


It’s possible to directly heat a house with active solar technology, from panels that circulate hot water through tubing or capture sun-warmed air to blow into a home. But the fastest growing trend today is to use solar-electric—or photovoltaic—panels to generate power to operate electric heating options such as heat pumps.

Used in conjunction with an air-source heat pump, solar-electric panels can supply power when the sun’s shining and bank credits with your utility for when it’s dark or too cloudy. As solar panel prices have come down and heat- pump performance has ramped up, this marriage of the two technologies has created a synergy that’s appealing to many Mainers, because it offers the promise of stable, long-term energy bills.

mike tabone solar panelsFor Sam Zuckerman, owner of Maine Solar Solutions, approximately two-thirds of his solar customers also choose to have air-source (mini-split) heat pumps installed in their homes. “This allows them to have a quicker ROI and reduce their onsite carbon footprint,” says Zuckerman.

Prices vary, but a typical home installation costs around $15,000. A 30% federal tax credit, which is set to expire at the end of 2016, reduces this by a third. Coupled with Efficiency Maine’s incentives for heat pumps, up-front costs can be significantly reduced for an entire system.

“If you factor in the 30% federal tax credit and assume a moderate annual increase in electricity cost, a well-designed

solar electric system will pay for itself in around nine years,” says Zuckerman, after which, the electricity generated to heat your house can be produced relatively free, reducing future heating costs considerably.


While geothermal heating systems are among the most expensive to install in Maine, they deliver great return on investment and the lowest heating cost of any of the options presented in the Efficiency Maine cost comparison for home- owners willing and able to make the up-front commitment.

Most common in new construction where the greatest efficiencies can be achieved, the up-front cost of installation in a 2,000 square-foot home is at least $28,000. But that cost can be offset by a $5,000 rebate from Efficiency Maine and a 30% federal tax credit, reducing the minimum bottom line cost to $16,100.

The high investment cost has been a barrier to geothermal in Maine. In the past two years, only 137 home systems applied for rebates, according to Efficiency Maine figures.

But Martin Orio, president of the New England Geothermal Professional Association and director of business development at Northeast Geo, says a few dozen HVAC companies in Maine now install the systems. He spends some of his time trying to educate people about the benefits of geothermal for both heating and cooling.

“People tend to get confused with geothermal heat pumps,” he says. “Think of geothermal as nothing more than a solar energy management device where the heat is taken from the earth rather than directly from the sun. And the only difference between an air-source and geo- thermal heat pump is that heat is extracted from the outside air rather than from underground.”


Photo: Smith & May

Photo: Smith & May

Wood pellets have become Maine’s pivot from the lumber industry. Four pellet mills process lumber-yard leftovers, in the form of saw- dust, chips and culled trees. In recent years, a distribution system for bulk delivery has grown up to truck pellets by the ton to customers statewide, making delivery as simple as it is for oil. Retailers, from big-box to hardware stores, also sell pellets in 40-pound bags, as well as the stoves in which many people burn their pellets.

Wood pellets seem to hit a sweet spot for home heating. They are a low-cost, renewable fuel with low air emission. And they are primarily a Maine-grown resource, although bagged pellets also come from Canada and at times from other U.S. states.

“Maine is the leader in automated pellet boilers, with more installations in the past two years than all the rest of New England and New York,” says Fischer at Efficiency Maine, which offers a $5,000 incentive for pellet boilers. These central heating systems are an alternative to oil or natural gas-fired boilers.

Those incentives have helped spur sales at Maine Energy Systems in Bethel, which assembles and sells an Austrian-made system, and Interphase Energy in Portland, dealers of the Kedel pellet boiler from Denmark.

“Oil prices are extraordinarily low today. But classic fossil fuel price patterns and environ- mental and regional economic opportunities still compel people to buy pellet boilers,” says Dutch Dresser, managing director at Maine Energy Systems. Another option, for those heating with cordwood stoves, is compressed wood blocks. Dominant brands such as Bio- Pellet, from Connecticut, and Canawick, from New Brunswick, Canada, compress sawdust and chips into various sized blocks. The wood is kiln-dried with a moisture content of roughly 5 percent, so they burn hot, produce little ash and give off few air emissions.

Wood blocks are sold in small packages, or can be delivered to your home on one-ton pallets. For homeowners who have historically heated with cord wood and are seeking a less labor-intensive option without any systems upgrades, wood blocks are worth considering.


Maine is more than 90 percent forest, and cordwood has been a low-cost, home-grown heating source here for generations. But to really get the most out of cordwood, it has to be split, seasoned, dried and burned in an efficient stove or boiler.

The moisture content in cordwood typically varies from 55-10 percent. The drier the wood, the better the burn and the higher the heat content. That’s obvious, but not widely appreciated.

“Cordwood with 10 percent moisture content releases around 7,500 BTUs, while wood with 55 percent moisture content has about half the BTU capacity,” says Adam Sherman of Biomass Energy Resource Center in Burlington, Vermont.

At the very least, wood should be split and left outside to dry for the summer, according to the Maine Forest Service. A year would be better. Then it should be put under cover and kept dry from rain and snow. If that’s not practical, consider buying kiln-dried wood. It’s more expensive, but will give off more heat and produce less creosote, which can cause a chimney fire.

“Where we’ve seen huge efficiency gains for consumers is kiln dried cord wood,” Sherman says.

Also, burn wood in stoves certified by the federal Environmental Protection Agency. These stoves limit the amount of particulate emissions heading up the flue and into the air. Old cordwood stoves can be a major source of air pollution. But new EPA standards introduced in 2015 will further reduce air pollution from wood smoke in future models.

All of Maine’s fuel options have benefits but the nuances of each, whether up-front capital, ease of use or ROI will determine the best fuel for your home. Lower the load, measure the BTU requirements and then upgrade to the fuel system that fits.

Colin Boyd, Tux Turkel, Steve Konstantino and Bill Bell contributed to this article. “Heat of the Moment” ran in the Fall 2015/Winter 2016 issue of Green & Healthy Homes magazine.

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5 Responses to “Heat of the Moment”

  1. Brandon Bernard January 3, 2016 at 1:39 pm #

    Great piece! You can’t beat the combination of a heat pump and wood stove for cost-effective, reliable, heating AND air conditioning. Pair the heat pump with a solar electricity system for clean power without worrying about CMP rates going up.

  2. Kody Loveless June 30, 2016 at 10:10 am #

    Thanks for the information. My wife and I are building a new home, and want to make it as energy efficient as possible. I really like the idea of solar heating. This seems like a great idea. Does this work well in the winter? Can you still get enough sun light even in snowy areas? I think I will have to look into this idea a little further.

  3. April Cook July 13, 2016 at 3:30 pm #

    It was interesting to see that petroleum can be blended with other oil without needing any modification to the fuel lines. If you want to go back to pure petroleum would you need to clean out the lines at all, or will they clear out on their own eventually? I also love that biofuel are a renewable resource. Thanks for sharing all this great information. http://www.middletonpetroleum.com

  4. Alan September 6, 2016 at 12:14 pm #

    Wood may be renewable in Maine but Britain seems to be the first country to find that it is only theoretically renewable as the Daily Mail headline asks, WHERE HAVE ALL THE TREES GONE ? Clearing trees in Alberta and British Columbia for firewood is troubling as the trees are already being cleared at an alarming rate for lumber and paper. The old CSA approved wood stoves were a failure in terms of reducing emissions so it is doubtful if the new models will be any better.

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