Warming Trends

Warming Trends

Do your utility bills leave you feeling burned? Learn what’s new (and not) on Maine’s heating landscape and which technologies deliver the most BTUs for your buck.

dog sleeping by fireplace

From our Winter 2018 issue

Any old Maine house worth its salt will contain a minimum of two heating systems, because no self-respecting Yankee would discard a perfectly good, broken furnace. In special cases, a house will contain the full suite of perfectly good obsolete technologies, from the original fireplace, to a century-old coal furnace, a mid-century oil boiler, an airtight woodstove from the 1970s, and some electric baseboards or a hospital-beige kerosene heater from the 1980s. It’s good to have options.

So where are we headed now? What’s the next latest, greatest thing?

“Well, that’s complex,” says Dylan Voorhees, climate and clean energy project director at the Natural Resources Council of Maine, sounding a little baffled himself. “The big trend is ductless heat pumps. But a lot of people are looking to propane — and I don’t really know why.”

Propane gas may be riding the coattails of natural gas, which has recently become popular in more populous areas of the state. New natural gas boilers can be small, quiet, and dazzlingly efficient. Although propane boilers can be too, that fuel has to be hand-delivered to your house. Additionally, a winter’s worth of propane costs even more than old-fashioned oil.

Not that oil is old fashioned in Maine. While the rest of the nation has largely abandoned oil heat in the past 50 years, two-thirds of Maine homes still rely on it, consuming an average of 900 gallons per house, per year.

“The transportation network that delivers oil to the farthest-flung addresses makes it an easy solution, if not a cheap or green one,” Voorhees says. “It’s been so entrenched here for so long that breaking into that market can be hard.”

And, frankly, the same can be said of wood. Maine is second only to Vermont in its reliance on ye olde woodstove. In short, the state’s heating landscape is eerily unchanged since the mid-century.

But electric-powered heat pumps may break the spell. Efficiency Maine — the state’s administrator for energy efficiency programs — tracks the popularity of heating systems by the rebates people apply for: Heat pumps are beating forced–hot-water boilers six-to-one.

Electric heat earned a ghastly reputation in the 1980s after electric rates drove heating bills through the roof. But the real “fuel” for a heat pump is outdoor air. Even the coldest of January air contains heat, and heat pumps concentrate that warmth and transport it indoors.

Although heat pumps (like most systems) may struggle to keep a leaky old house at 70 degrees on a particularly frigid night, the technology continues to improve. And anyway, that’s why you keep an old woodstove in the basement. It’s almost perfectly good, and it’s nice to have options.

So how does your fuel stack up in terms of cost, efficiency, and environmental impact? Consult our primer to determine where you stand and if it might be time to make a switch.



heating your home with oilNationwide, oil displaced coal and wood in the early 1900s. Unlike coal, which homeowners had to shovel into the boiler at regular intervals, oil could feed itself into the boiler for weeks, supervised only by a thermostat.

While natural gas has conquered much of the country, Maine’s rural character has helped to keep oil in command. (Running gas pipelines to remote areas doesn’t make logistical or financial sense.) As a result, the distribution system is excellent, the boilers are cheap, and when something breaks, there’s someone nearby who can fix it.

Pros: Low cost to install. Supported by plentiful oil dealers and technicians.

Cons: Price fluctuates. Fossil fuel. Big carbon footprint.

Annual Heating Cost: $2,000–$2,500

Ways to Save: $500 rebate, and financing, through Efficiency Maine. Also, plan to fill your tank in the summer when oil prices are lower.


When natural gas heat gained traction in the mid-1900s, installing the buried pipelines paid off quickest in densely populated urban areas. Natural gas heats about half the homes in the nation now. But it fuels only 5 percent of Maine residences.

heating your home with gasWhere natural gas is available, super-efficient gas boilers have become very popular. These direct-vent boxes the size of a large suitcase can silently handle heat and hot water, and burn at efficiency rates in the high 90s. Note that propane (a.k.a. bottled gas) is a completely different product, and is much more expensive.

Pros: Low cost to install and feed.

Cons: Substantial carbon emissions. Natural gas is often mined with “fracking,” a practice that requires vast amounts of water, often transported to remote locations. There are also concerns that the potentially carcinogenic chemicals used in the extraction process may contaminate groundwater.

Annual Heating Cost: $1,600–$2,200

Ways to Save: $500–$1,000 rebate, and financing, through Efficiency Maine.


heating your home with firewoodWe humans have been warming ourselves with wood for eons. Only in recent centuries did coal gain significant market share; in the mid-1900s, oil and gas pushed aside both wood and coal. But wood remains the primary heat source for more than 10 percent of Maine homes.

Both cord wood and wood pellets, made from compacted sawdust, are “heat local” options that support the Maine economy. But only pellets give you the option to replace an old burner with a new one that can heat an entire house without regular attention.

Pros: Local. Renewable. Cozy.

Cons: Burning wood releases far more particulate pollution into the air than burning oil or natural gas. Pellet burners produce dusty ash and may need frequent cleaning.

Annual Heating Cost: $2,000–$2,500 for pellets

Ways to Save: Financing and reimbursement of one-third of the project cost (up to $3,000) through Efficiency Maine. Also, keep it dry! Moisture in your wood or pellets ruins its burning efficiency.

Heat Pump

A heat pump hanging on the wall may look like a misplaced breadbox, but it acts more like a brass lantern holding a magical genie who doles out wishes. It conjures heat from thin air. It can also conjure cold air from thin air, granting you air conditioning. For an encore, it can make your heating bill shrink.

getting a heat pumpEven in the draftiest old house, swapping out an aged fossil-fuel system for heat pumps will usually lower your heating cost. Furthermore, the electricity heat pumps need can come from many sources, including homegrown solar and wind.

Pros: Low operating cost. Room-by-room zoning. Can provide cooling. Adapts to various electricity sources. Low carbon footprint.

Cons: You may need a “head” in each room, which gets pricey. And you may need a backup plan on super-cold nights.

Annual Heating Cost: $1,300–$1,600

Ways to Save: $500–$750 rebate, and financing, through Efficiency Maine.


An Ounce of Prevention

Pop quiz! When it’s cold outside, the cheapest way to warm up is to:

A: burn more oil B: burn more gas C: burn more wood D: close the window

Answer: D. Congratulations! You just discovered the “negawatt,” the fuel you never use in the first place. It’s free, it’s clean, it’s renewable, and it can help lower your heating bills no matter what your fuel source. Here’s how to harvest negawatts in your home.

Plug holes. If you combined all the small holes in your house — a cracked basement window, a loose dryer vent, a crooked front door, a leaky fireplace damper — you might have a cavity large enough for a cat to saunter through. Hunt down the gaps and seal them with caulk, weatherstripping, or spray foam.

Insulate the attic. Heat wants to rise, up through the attic and out into space. An attic should have at least a foot of cellulose or fiberglass insulation in place, and ideally more.

Draw the drapes. Contrary to popular opinion, replacing single-pane windows with double-pane units can have a very slow payback period — think 20 to 30 years. Adding window dressing (shades, curtains, or both) is often cheaper. Close them at night to hold in heat. (Extra credit: Close them on summer days to keep heat out.)

Zone, zone, zone. Not every old house has been updated with zoned heat. But most of those houses have doors. Shut them strategically to prevent heat from rushing up the stairs or into a cold foyer.

Heat Pump Parlance 

AIR-SOURCE When you see a long, white box hanging high on a wall, it’s likely an “air-source” heat pump. It’s connected to an outdoor unit that works just like an air conditioner to harvest heat from the air.

DUCTLESS Means the system doesn’t require the big ducts that older heating and cooling systems use.

GROUND-SOURCE A heat pump with a condensing unit that squeezes heat from the (relatively) warm earth or water. Geothermal and pond systems are still in their infancy, and installing them can cost $35,000 to $60,000.

HEAD The indoor unit. Typically wall-mounted, a head may also be installed on the ceiling or as a floor console.

MINI-SPLIT Refers to the split between the indoor head and the outdoor unit.

MULTI-SPLIT A system where an outdoor unit serves multiple heads.

REVERSIBLE The system can be “reversed” with the touch of a button, to provide cooling instead of heating and vice versa.

REMOTE The head can be set and adjusted with a remote control.

SEER The efficiency of a heat pump is stated as its “seasonal energy efficiency ratio.” The EPA’s Energy Star program requires a SEER of at least 15. (Higher is better.)


Bill Bell, executive director of the Maine Pellet Fuels Association
Governor’s Energy Office

Naoto Inoue, president of Solar Market in Arundel
Scott Libby, owner of Royal River Heat Pumps in Freeport
Andy Meyer, residential program manager for Efficiency Maine
Bill Morgner, president and co-owner of Mid-Coast Energy Systems in Damariscotta
Paul Shepherd, co-owner of Penobscot Home Performance in Bucksport
Dylan Vorhees, climate and clean energy project director at the Natural Resources Council of Maine