A little over a year ago I wrote a popular item on the dilemma of New Englanders who depend on oil for home heating. The pellet stove insert I’d installed in the living room fireplace a few years before was helping, but there was no way to distribute that heat. As oil shot past $100/barrel on the way to $140 it was clear I needed to find another way to fuel our hydronic central heating system.

My research led me to a couple of options. First, a pellet boiler. Second, a wood gasifier. I chose the gasifier mainly to diversify my sources. Although I expect that wood pellets will remain available and attractively priced relative to oil, I didn’t want to make another bet on a commodity whose price I can’t control. I don’t produce the firewood that my gasifier burns, but if I had to, I could. A couple of crazy winters riding the oil-heat rollercoaster left me craving that assurance.

After further research and consultation, I settled on the EKO wood-fired boiler. It’s made in Poland by Eko-Vimar Orlanski, imported into the U.S. by New Horizon, and sold locally here in southern New Hampshire by Mechanical Innovations.

In May 2008 I bought an EKO-40 boiler. It arrived on a pallet a few weeks later, and was unloaded into my garage while I finalized my installation plan. Had I known that process would drag on for six months, I might have reconsidered my decision to inform the City of Keene about my plans, and apply for a permit.

But despite the incredible hassle I described here, I’m glad I did. From the start, I had two goals in mind. One was to make the house affordably warm for the first time in three winters. The other was to be able to write this essay.

Wood gasifiers aren’t new technology. Northern Europeans have used them for many years. But they’re new to the U.S. Most of our city housing officials and our insurance agents don’t know about them. Now mine do, and I hope what I’ve learned will help validate this solution elsewhere.

From the city’s perspective, the issue was code. The main objection was that the code requires U.S. certification (UL, ASME), but the EKO is European-certified (TUV, CE). When I dug further, though, I found that the UL 391 sticker — which the city initially said was needed — doesn’t apply to solid-fuel-fired boilers. What does? UL 2523, a standard that’s currently in development and to which no products are yet certified.

Eventually I engaged an engineer, Mark Vincello, to look at the boiler, confer with my dealer/installer, Bob Jennings, and write the city a letter saying that the boiler was well-made, had been pressure-tested, and would be safely installed.

In October, I finally got my permit. For the record, I want to thank the city’s chief building officer and assistant director, Medard Kopczynski. Like many code-enforcement departments, ours is widely criticized for, among other things, resisting innovation. But although Med had never seen or heard of a residential wood-fired boiler, he was intrigued by the solution, and worked with me to find a way to approve it.

With permit in hand, I contracted Bob Fairbanks to line the chimney I’d be using. He installed an insulation-wrapped flexible liner. The boiler requires an 8″ liner and the chimney is 8″ x 12″, so it was a tight fit, but Bob “ovalized” (squashed) the liner and got it in.

By now it was November and the boiler was still sitting in the garage. The next hurdle, which gave me a few sleepless nights, was moving this 1500-pound beast into the basement, through a narrow entrance under the barn and then across the barn’s muddy floor onto the basement’s cement pad.

1: four eras of heating

It was kinda crazy. In the end it took four of us, a tractor, a pallet jack, a bunch of thick planks, and a bottle of dish soap. The tractor inserted the boiler into the barn. We slid it on soapy planks across the dirt floor, wrangled it onto the pallet jack, and then wheeled it across the cement floor to its current home.

Finally, in early December, Bob did the hookup and we fired it up. It’s been running continuously ever since.

In photo 1 you can see glimpses of all four heating-system eras my 1870 home has known.

The chimney, one of three, originally vented several fireplaces.

The brown box sandwiched between the green-and-white EKO boiler and the woodpile is a coal burner which must have supplemented wood heat at one point.

Then came oil. You can see one of two 250-gallon tanks in the corner behind the woodpile.

And now the EKO boiler, a modern, electronically-controlled device that brings us full circle back to wood.

2: hydronic hookup detail

3: hydronic hookup

Photos 2 and 3 show how the EKO ties into the pre-existing hydronic system. In photo 2 you’re looking at five circuits. Right to left, corresponding to four circulator pumps, are three house zones and a water heater circuit. The leftmost fifth circuit runs through the EKO.

Backing away in photo 3, you can see the EKO on the left, and all five inputs to, and outputs from, the oil burner at bottom right. The EKO is hooked up in series. This costs me some efficiency because, although the oil burner rarely runs, its water jacket soaks up heat. But that may be healthy for it, and though mostly sidelined it’s still a crucial piece of the puzzle.

If the EKO’s water jacket drops below a set temperature — currently 140F — the fossil fuel furnace kicks in automatically. Among other things, that means we can go on vacation without worrying about frozen pipes.

Photo 4 shows parts of the control and safety systems. The green tag is hanging next to a pressure relief valve. If the boiler were to overheat, that valve would open and dump water out onto the floor.

4: relief valve, circulator pump, pump switch

The red circulator pump appears near the center of the photo. The green box at top left activates the circulator when the boiler’s water jacket reaches a threshold currently set at 160F, and then keeps it on until the water temp drops below 140F, at which point the oil burner kicks back on. With the EKO running continuously, the EKO’s circulator can, and does, run for days, idling the oil burner completely.

5: sensor and high-temp cutoff

Photo 5 shows a sensor that’s been placed directly on the boiler’s water jacket through a hole drilled into the top cover. Its signal travels to the digital controller shown in photo 7, which actuates the pump switch in photo 4. It also controls a safety cutoff, shown at the bottom of photo 5, that would shut down the boiler (electrically) if its temperature went above 210F.

In photo 6 you see the EKO’s control panel. The dial controls the setpoint, which is currently set to 165F. Because the current temp in this photo is below that, the EKO is running in gasification mode. Once it reaches the setpoint, it drops back to idle mode.

6: eko control panel

There are a bunch of menu options here, but so far I’ve only had to fiddle with the setpoint and the fan control. Gasification works by way of a downdraft that sucks wood gas from the firebox in the top chamber down into a bottom chamber where superheated combustion occurs. In idle mode the fan runs at 40% capacity. In gasification mode it can run from 50% to 100%. I’m currently running at 60% unless it’s really cold (10F or below), in which case I bump up to 70%.

This isn’t ideal. I throttle back to keep the boiler from running too hot. Even when idling, there’s a minimum amount of heat produced, and it has to go somewhere. In the ideal scenario, you run flat out in 100% gasification mode and charge up a big thermal battery — e.g., a 500-gallon insulated water tank — then draw on that stored heat. That would be the most efficient, cleanest-burning way to use the EKO.

But the current setup was already a financial and logistical challenge so, like a lot of folks, I’ve punted on the storage tank for now. Meanwhile, we’re thinking about extending a circuit to the attached barn where Luann has her studio, which is currently heated by propane. If we do that we’ll give the EKO more water to heat, it’ll work harder, and it’ll be happier.

7: digital controller

There’s one more safety feature related to overheating. In addition to the relief valve and the high-temp cutoff, the digital controller can activate one of the house zones (the biggest one) and dump excess heat there, even if the zone isn’t calling for it.

The controller appears in photo 7. It senses the EKO’s temperature, switches the EKO’s circulator pump, and controls its high-temp cutoff (see photos 4 and 5). It also controls the fossil fuel furnace, turning it on when the EKO’s water drops below 140F, and off when it rises above 160F.

8: heat-exchange cleaning lever,
damper open/close rod

Photo 8 shows the only two manual controls. The lever at top left cleans the heat exchanger. You just give it a stir whenever you load wood.

The rod with the ball handle opens and shuts the damper. Here it’s pulled out, the damper is closed, and the boiler is running. To load fuel you push in the rod to open the damper, power down the fan, and open the firebox door. When you’re done you shut the door, pull out the rod again to close the damper, and power up the fan.

9: upper firebox

10: lower gasification chamber

Photo 9 shows the firebox. It’s big, you can load four or even five good-size armloads of split wood. The slot in the bottom connects the top chamber, where the wood burns and emits gas, to the bottom chamber, where gasification occurs.

Photo 10 shows the gasification chamber. You can see the same connecting slot, here from the bottom. Remember, the wood fire burns in the top chamber. Some people like to say that wood gasifiers burn upside down. There isn’t a lot of heat in the top chamber, and the stack temperature runs below 300F. The real heat happens in the bottom chamber.

11: firebox in action

12: gasifier in action

Photos 11 and 12 show the two chambers in action. In photo 11, I’ve lit a wood fire in the cold, freshly-cleaned boiler. You just use newspaper, kindling, and a match, as with any wood fire.

In photo 12, a few minutes later, I’ve loaded more wood into the top chamber, shut the damper, and powered up the fan. What you see, and hear, is like the exhaust from a small rocket engine. At full blast, the temperature approaches 2000F.

A couple of minutes after photo 12, the readouts in photos 6 and 7 hit 160F, the oil burner clicked off, the EKO’s circulator pump clicked on, and my wood-fired central heater was back in action.

Today’s January 11, and it’s been running since Dec 4. There isn’t much maintenance. I should clean out the ash (and scrape out the creosote) weekly, but I’ve probably only done it three times since I started. Photo 13 shows the entire quantity of ash I’ve removed. As you can see, it isn’t much. The EKO has turned a lot of wood — I’m guessing close to two cords by now — into a very compact volume of powdery ash.

13: five weeks of ash

Two cords? I know. Although it does burn for a long time — a full load can go from eight to twelve hours, depending on the outside temperature — this thing eats wood for breakfast, lunch, and dinner. I bought six cords of semi-seasoned wood, it’s only January 11, I may need to supplement with some seasoned wood come March or April.

Still, I’m OK with that. It’s wonderful to sideline the oil furnace. I’m not saving as much as I would have at $140/barrel oil, but I’m still saving. And I feel like I’ve bought insurance against price volatility that was driving me nuts. Lots of friends pre-bought oil at four-fifty or even five bucks a gallon. That bet paid off every year except this one. I hated living with that craziness.

At May 2008 oil prices, I was looking at a three- or four-year payback for this solution. That doesn’t seem likely now, but I don’t regret the decision. The house is future-proofed with a flexible trio of heating systems. There’s the pellet stove which I still use in spring and fall, the wood boiler for winter, and the oil furnace for backup and for summertime water heat.

There’s been no help from the federal government, by the way. I did some research last fall to find out if my investment in this solution would qualify for a tax credit. According to energystar.gov, there is a tax credit for biomass stoves. But not for 2008. I’d have had to wait another month to earn 2009′s $300 credit. Oh well. EKO-Vimar probably doesn’t provide the manufacturer’s certification statement anyway.

To be honest, I’d rather be living in a smaller, newer house that doesn’t need a furnace. Maybe someday I’ll be able to gut and super-insulate this old house. But meanwhile, like nearly all New Englanders, I’ve got to burn something to survive winter. Most of us still burn oil. But some of us are going back to the future. It’s 1870 again with a twist. We’re burning renewable biomass in clean, efficient, smart appliances, and pumping dollars into the local economy. It’s a start.