In past years, my good friend D. and I had similar heating systems: oil boilers and old-fashioned cast-iron steam radiators. As of last autumn, though, J. & I had just bought a new old house with no heating system at all, and D. had just ripped his heating system out– leaving us in the same boat of starting more or less from scratch, heating-wise. D. wound up installing a Viessmann condensing natural gas furnace driving a system of hydronic radiators. The Cold House wound up with a Jøtul wood stove. We’re both very happy.
These systems have something in common: arguably, they are both among the lowest-environmental-impact heating-retrofit options readily available (barring still-somewhat-extreme options such as geothermal and solar applications). As such they both qualified for federal tax credits. In every other way, though, they are just about polar opposite. Which is better depends entirely on your lifestyle, expectations, and personality. Here’s the main control area of D.’s system:
The burner (far right) actually condenses the water vapor in its own exhaust to reclaim that heat; in this way, it has around 90% efficiency (compared to the 80% or so of our old oil burners). Burning natural gas, it emits almost no particulate pollution– basically, just CO2 and liquid water. The burner heats water, and electric pumps circulate the water into the orange plastic tubing, which then delivers it to and from radiators throughout the house. An array of valves and electronic thermostats allows D. to fine-tune three (or maybe four?) “zones”– cellar, first floor, second floor– such that the temperature in different parts of the house can be adjusted independently. It’s a pretty cool system– efficient and flexible. It was very complex to install, but is very simple to operate. I think it cost somewhere in the range of $8-10,000, with some homeowner-labor involved.
Now, here’s our “system”:
Our wood stove has about 75% efficiency. It is considerably more efficient, and emits much less smoke, than wood stoves of 20 or 30 years ago– but still, it is less efficient and has higher emissions than D.’s gas burner. On the other hand, it burns a renewable fuel which is grown within 50 miles of the house, rather than a fossil fuel shipped from across the country. The stove has three moving parts: the door, and two manually-operated air vents. (Piper, shown, does not count as a “moving part”, because she rarely moves.) Compared to the dozens of electrical moving parts of D.’s system, I consider ours reassuringly simple, and it works even when the power’s out.
On the other hand, nothing happens automatically– adjustments require human attention, and are prone to human error. We occasionally over-estimate on the wood firing, and get the living room warmer than we intended– that’s wasteful, and wouldn’t happen with an electronically-operated hydronic system. Also, the stove obviously has but one “zone”– right where it is. We do have our own, neolithic system of “zone heat”, which involves blocking off the upstairs with a quilt in the doorway. But we don’t have the option of deciding that we like having the bedroom at 58º, and keeping it there every night. We get what we get, more or less. And to the extent that some people might be able to tolerate lower temperatures, if the temperature was at least steady and predictable, the more complex system might be better.
In terms of capital investment, the wood stove and chimney cost about $3,200. If we’d put in three stoves, to create a real “zone” system, the total might’ve been about the same as D.’s system.
Lastly, there’s the question of aesthetics. Here, truly, I am torn. The mystic in me adores the ever-changing sight of a fire, the glow of coals in the evening, the feel of each unique stick of wood, even the oaky aroma of our wood pile. But the geek in me is in awe of the systemic beauty and elaborate automated function of D.’s heating system. D’s two-year-old son seems to shares this appreciation; each time I visit, he says “Viessmann – downstairs – basement”, and we go down to admire it.