This small heater warms an 11 x 11 (120 sf) guest cottage in Portland, OR. It was built over a concrete slab floor, and the walls are straw-clay with earthen plaster. The heater itself takes up about 1/3 of the room, with a 4' by 11' footprint, including a 4 foot by 7 foot bed (twin size).
Because the heater is not used full time (it's a guest room), we do not have accurate figures for annual wood consumption. Even with long term guests, the owners generally only fire the heater every other day, and the building and bed store the heat for two days' comfort.
Standard features on these as-built drawings include scale drawings; top, side, and front views; course-by-course layouts for the brick firebox and plinth; ducting layouts; and general information about thickness of masonry and so on. Some familiarity with earthen masonry (or any heat-tolerant masonry) is assumed; resources are suggested if you need further info on earthen masonry techniques.
We also include a generic cutaway drawing and some notes for discussion with housmates or building professionals. Please note that we are not licensed architects or engineers; no guarantee or warranty is implied, and these plans may not meet local jurisdictions' requirements for permitted installation. In particular, this heater was installed before Portland, Oregon developed a standard for rocket mass heaters, and might require greater clearances if built today in a room with combustible walls.
Builders' notes detail the basic construction process, and note special differences from standard construction, including the fabrication of a bypass connection.
A bypass from manifold to chimney allows priming the heater more easily for cold starts. (This is useful for an occasional-use space such as a guest room, or anywhere that the heating season is variable enough that you might burn less than once per week.) While the bypass does also allow for short-term firing without heating the main mass, these are primarily a heating stove and probably not suitable for summer cooking.
This PDF file prints 6 ledger pages (11 " x 17"), with full color illustrations including photos and vector-line diagrams. Most local print shops can print this (double or single sided) for under $7.
How to purchase:
Choose your payment option. Once payment is made, a link will magically appear in a purple box at the bottom of this post.
Click the 'Click here to download' link, and SHAZAM! Your file is downloaded.
Hey I bought it and it looks great! Love what you and your husband are doing. Hope to see you guys again at the mother earth fair in PA this year
www.dennisalan.com just starting my homestead and i want to build around a rock mass heater!!
City Boy Homesteader
Yay! It's working!
Thanks, Tracy, for posting these on our behalf.
Ann and Dennis - Thanks for being our first customers on the new Permies premium content!
This thread would be a great place to mention any questions about the plans, especially if something is unclear.
It would be OK with me as the author if you want to take a screenshot to ask me about a particular detail. Please don't show the whole page of the plans, just the portion of the diagram that was unclear to you. (Believe me, I will recognize it!)
As a Permies staff/moderator, we might use our special powers to edit or remove the screenshot after we've resolved your question.
If you're new to reading building diagrams in general, you may also want to check out the notes on "Architectural Drafting" that I added in our Everything Combo thread.
Click Here for the Everything Combo thread.
In our limited free time these days, we still participate on these forums and give free advice to rocket project folks and others. I will make these premium threads a priority.
Please post a link here if you have a project thread about a mass heater you've built, or are building, with our Daybed 6" plans. It's a great way to ask for help and advice, and share your progress with interested Permies fans.
I will check out those links as my time allows, too. (Feel free to send me a PM, with a link, if you want my attention sooner on a particular project or thread.)
And please reply to this thread with "baby pictures" of your finished projects, warm pets melting onto the bench, happy mammas and babies, and all that good stuff!