Do you remember how glowingly I spoke of rocket mass heaters? How excited I was to have one as the primary heating system in our home? And it wasn’t just me- Shane was equally enthusiastic about the technology, possibly even more so. The potential to build our own heating system, for relatively little money, the possibility of storing heat in mass- that would in turn provide a cozy sitting area, the efficiency of the burn, our very positive experiences with rocket stoves– all of these qualities made rocket mass heaters extremely attractive to us. Add to that the fanfare, oh the fanfare…
Well I can’t stand rocket mass heaters. I would never build another one, unless I had an immense amount of time on my hands with absolutely nothing better to do and wanted an outdoor bench as a novelty item to be used periodically in the cooler fall months. And I’ll tell you why…
They are extremely finicky. It can be exciting during the build: getting the measurements just right, reshaping the bell chamber, getting the length of run perfect for maximum efficiency. Sure, it wears on a person after a while, but there is immense satisfaction in finally getting the bloody thing just right. That rocket sound when everything is working perfectly- WOW! But don’t get too excited- just because it’s perfect, doesn’t mean that it will work all the time.
If there is a strong wind, or say very cold temperatures (hello Canadian prairie!) all bets are off. Now you’ll have to fight a down-draft, or a nice column of very heavy cold air. Good luck getting that thing started. Oh sure, you can open a window to rebalance the air pressure, install a fan in the pipe to try and combat the problem- and if you’re persistent (like Shane) you may even get it started. This time. But try again the next morning when your wife has already moved out in frustration and you’re feeling blue- and very cold.
And then there’s the fact that you must not have any other occupation. This is perhaps appealing to some- say monks, or hobbits- who might have all day to contemplate life and feed the fire. But the average person cannot sit by the feed tube all day long, feeding the endlessly hungry beast little pieces of wood lovingly chopped down to (again) just the right size. I can only imagine what was going through Shane’s head (because again- I wasn’t here) but I’m betting it wasn’t, “man am I glad to have all of this time away from all of the other tasks on my list. I hope that I can do this every day.”
And then there are the marvellous fumes. You can’t actually close the top of the stove, for very long anyway, because you need to keep feeding it (remember?) and it needs a bit of air. This is no sealed unit you’re dealing with. So if you have breathing problems to start with, or allergies, you’ll enjoy hours of feeling like someone has your lungs in an iron grip and is slowly squeezing the air out.
There are positives. The mass does actually retain the heat for a good while. And since you can’t leave the heater during your waking hours you will get to enjoy that cozy warmth under your bum, periodically, when you’re not up and feeding the thing more sticks. But that mass does relatively little to add heat to a cold room. And it is indeed efficient- there is hardly any ash left over after burning piles and piles of expertly chopped sticks. And you can shape it to look like a dinosaur, or a mermaid, if that’s your thing.
Unfortunately the negatives far outweighed the positives for me. We tore the f*cking thing out and replaced it with a Blaze King Princess (thank you Analogman, for the very helpful advice and support). Guess what? The house is perfectly comfortable now, and it’s only been in two days. Last night, in fact, I was broiling while we watched movies in our new home and had to strip off the layers of clothing I was convinced would become my new second skin. The fire was still going this morning and kept the temperature of the house comfortable enough that I don’t even require layers. Shane didn’t even need to add wood right away- he just increased the temperature and the fire burst back into life. Yes Virginia, there is a Santa Claus.
There’s been no fumes, no leaks, no fighting down-drafts, no fighting air pressure, no swearing and threatening to leave the country for warmer climes (though I could use a vacation after all of our troubles)… Imagine that. Just warmth and comfort.
And before any rocket mass heater fans (I know you’re out there- and fanatical) write me about how we should have stuck it out, or tried a few more things- save it. The reason we embarked on this experiment was because- between a technologist and scientist- we’re game to try out just about any neat sounding idea. And we understand that no experiment goes right the first time, or the second time, and sometimes not the twelfth, or the twentieth time. We’re perfectly comfortable with reworking a project dozens of times to get the predicted results. We’re very accustomed to making adjustments, and careful measurements counting. The build was perfect but this idea does not deliver. Not in our climate and not, in my opinion, as a safe and effective indoor option. And no- I wouldn’t use it in a greenhouse either (as we at one time planned on doing) because I don’t expect to want to sit in a greenhouse long enough to get the mass up to the right temperature to be helpful.
I have a lot of cleaning to do now. Taking out a huge section of the mass heater made quite the mess and there’s dust everywhere. But I can comfortably do that now- in my underwear if I so choose.🙂
*I’d be remiss if I didn’t say a special thanks to Chad at Fireplace Stove World, in Edmonton, who was immensely helpful and patient with me, even though the road conditions (and lack of heat in days, feelings of total hopelessness, etc) had me in a terrible state by the time I got there. Thank you.