A RUMFORD Fireplace.

Rumfords are a joke in green homes. The only thing good about them is that they are better than the worst and most poorly conceived masonry fireplaces. Every bit of combustion air is still drawn from within the home. Worse yet, every bit of air that is heated, expanded and escapes up the flue has to be followed by air infiltration somewhere else. They may have gotten a pass because they burn wood better than other homebuilt models, but that doesn't mean there is anything efficient or useful about them for tight homes.

Right, fireplaces are bad in general and Rumfords are lousy unsealed fireplaces. No one with a full deck would put a fireplace in an energy efficient building. Modern wood burning appliances are the way to go or consider a masonry heater, our personal favorite. Likely the only reason masonry heaters have not become more widely accepted is expense and the fact that the home has to designed around it, sort of like a passive solar home.

the issue I have with masonry heaters is simply that they continue to radiate heat after the fire goes out - that is their stated advantage. in a superinsulated house requiring very little added heat, this would likely lead to overheating with no way to stop the heat.

I agree with you on putting a fireplace in such a building, but if one does it, a chimney top damper combined with an insulated, gasketed removeable door covering the firebox does help keep air infiltration at a minimum. One also needs a direct air supply to the FP in order to use it.

the issue I have with masonry heaters is simply that they continue to radiate heat after the fire goes out

The best place for thermal mass is in a water tank. Then you can run the water over the roof for radiant cooling or through a wood boiler for heating with wood.

The fact that masonry heaters continue to slowly radiate heat after the fire goes out is precisely what we like about them for use in energy efficient homes. If you burn say 20 pounds of dry Douglas fir (@9250 BTU/Lb) in a 93% efficient masonry heater, it will evenly generate approximately 7,169 BTU/hour over an approximately 24 hour period. If you do this in a conventional woodstove of same efficiency, it will generate approximately 57,350 BTU/hour over an approximately 3 hour period. Here’s an excerpt from our masonry heater performance software instructions:

Energy efficient homes may only require 3,000 to 8,000 British Thermal Units (BTU) of heat gain per hour. For most conventional woodstoves, this is well below their critical burn rate for operating cleanly and they will start to smolder. If you operate most conventional woodstoves at or above their critical burn rate, you may easily overheat an energy efficient home. The only solution for this dilemma is to have many small firings, which is not very convenient. Therefore, wood burning and energy efficient homes are not normally compatible unless you have some way to burn the wood at or above the critical burn rate to allow operating cleanly and you have a way to store the excess heat that is created and release it as needed without having to accomplish frequent, inconvenient firings.

We prefer masonry heaters which provide the solution to this problem and have actually been the most efficient way to heat a home with wood for over a hundred years. Unlike fireplaces or woodstoves, there is very little heat loss because the exhaust gases are circulated through the masonry heater several times before going up the chimney. There is very little pollution because masonry heaters burn the wood very quickly and operate at about 1700 degrees so as to fully burn what even certified woodstoves cannot burn. Masonry heaters store and slowly release radiant heat over a 24 hour period accomplished by only one or two firings per day. Masonry heater surfaces never get extremely hot like stoves and do not overheat and excessively dehumidify your home which your sinuses will greatly appreciate. A masonry heater can also be located to absorb solar radiation and store this form of heat energy too. Therefore, masonry heaters are similar and compatible with hydronic radiant floor heating and passive solar heating. As a side benefit, you can have a nice masonry oven that is available for energy free baking duties perhaps 10 hours per day and you can also have heated benches for you, your guests, and your pets to enjoy all day. Constructing a masonry heater is a relatively simple DIY project and there are many good kits available in the marketplace to do this. Please be sure to fully research and comply with all your local building code requirements.

http://www.borstengineeringconstruc...lator.html

Posted By sailawayrb on 18 Jun 2014 11:10 AM
Right, fireplaces are bad in general and Rumfords are lousy fireplaces. No one with a full deck would put a fireplace in an energy efficient building. Modern wood burning appliances are the way to go or consider a masonry heater, our personal favorite. Likely the only reason masonry heaters have not become more widely accepted is expense and the fact that the home has to designed around it, sort of like a passive solar home.

Wrong! There is an ORTON  version creating bad rumors (some sales idiot back in 69 who tried to improve on the RUMFORD by squaring up some of the round features that RUMFORD designed as a convergent duct venturi at the base of the box). RUMFORD took the side walls and converged them back at smaller right angles to reduce pressure, increase velocity, reduce turbulence, from the conventional square box popular design back in the 1700’s, brilliant for this time frame. It takes that velocity and boost it again like a turbo charger at the base of the flue. The high velocity, couple with an insulated fast reacting mass warmed the place up fast with low CO. The taller flame as a result of faster moving less turbulent laminar flow produced higher temps in the flue and a better burn. ORTON screwed that up with a slant forward back design thinking that would push more hot air to the interior, which it did, and more turbulence and smoke. The principles here are radiant heat and fluid dynamics. Where ORTON went wrong is creating a square edge “smoke shelf” smoke return back up from down drafts in a venturi that calls for smooth boundary layer flow out of the vacuum the venturi causes. We understand the same ‘streamlining’ today with boundary layer friction (turbulent flow) and heat, especially in pneumatics which this is too. So this whole idea of air moving in two directions, up and down, and designing to it vs high velocity escape gas is where ORTON followers went wrong. And from what I understand the guy was not an Engineer, he was a grocery store sales guy. Reminds me of some out here.

The engineering behind the Rumford makes perfect sense, to decrease the pressures and turbulences at the base of firebox and close the right angles to create a ‘convergent’ duct, then do it again at the base of the flu to increase velocity which moves CO out of the box faster than a conventional one, mass heater included. Now the concept has been 'modern' ized as Sali puts it but, does not understand, nor how to use an insulated material in the firebox and double wall flu that produces higher temps with same emissions speed to create a cleaner burn than a mass heater which has a higher potential for bad design smoke back.

 Yestermorrow School of Engineering hybrid design I posted that from two brilliant instructors that also wrote Natural Builders Companion you’ll find MANY tight not “green” homes if you will, but "natural" toxin free homes. The design I posted by them is a mass heater via all the earth, stone, and concrete, and RUMFORD hybrid but, without the toxins that are of a MUCH larger concern than ‘modern’ Rumfords in “green homes’ or the one they have installed in many of the tight certified homes throughout the northwest. That design is a natural ERV that replaces conditioned air with exhaust air.

Just goes to show, be careful of what you read on the internet, it may not the latest technology or best understanding or advice. Many just post bad info with no facts to prove bad designs by better builds of their own, or post their bad design or "opinions" as a standard, vs products and designs with proven data. Same thing that happen to RUMFORD back in the day.

Got to run, have to read the rest of the post tommorrow  

Irrelevant and more rubbish.

Wrong! There is an ORTON version creating bad rumors

You've completely sidestepped the real issues. We're not the EPA. I am not commenting on the burn "efficiency". Any unsealed fireplace represents a mighty large hole in a home's envelope and even worse when it is in operation. The burn may be "efficient" enough to get a pass from the EPA, but the actual efficiency and suitability for green building is bottom of the barrel.

Precisely and Yes, bottom of the barrel is a more accurate description of what we have here.

Posted By ICFHybrid on 18 Jun 2014 09:21 PM

Wrong! There is an ORTON version creating bad rumors

You've completely sidestepped the real issues. We're not the EPA. I am not commenting on the burn "efficiency". Any unsealed fireplace represents a mighty large hole in a home's envelope and even worse when it is in operation. The burn may be "efficient" enough to get a pass from the EPA, but the actual efficiency and suitability for green building is bottom of the barrel.

Posted By TLP on 12 Jun 2014 05:12 PM
Here is what some natural builders have done in Vermont and NE cold climate, little sun days, that build tight envelopes and toxin free, A RUMFORD Fireplace. BLOCKQUOTE>

I side stepped issues? What issues? I said the RUMFORD was installed in a " TIGHT ENVELOPE TOXIN FREE" above. You made some bad assumptions and created a false "issue" that does not exist. This RUMFORD I quoted is installed in a Newberry, VT home with a 4" pipe envelope penetration intake pipe and flue that blower door tested @ 3.43 ACH50? So tell me, what is the issue? I assume by your post you have an issue with 3.43? Are you claiming you were there and the builder is lieing? Or do you have build that is tighter with the same RUMFORD they used? The blower door test was done by third party Energystar rater, I guess you are challaging the builders rating and envelope? HRV-ERV have two envelope penertrations plus that required for the fireplace so what issue? This is one of 8 builds in 2011 with instumented test data in thier book appendicies, and there are many more with various forms of heating, cooling, and ventilation in green home "tight" proven builds ranging from 2.5-5 ACH 50.

The Renasissance Rumford installation has a 4" external penetration that has "ZERO" air infiltration as tested to R2000 industry standard "make-up air requirements". Buckly RUMFORD meets the same requirements. The 'positive' seal gasketed valve "air shutter" provides combustion outside air when the sealed box door is shut. Positive seal because when the valve is closed there is a positive vacuum on it due to the pressure difference between the valve and heated box. If you watched the video and read the manufactures specs you'd know that as they claimed, the RUMFORD if designed right is a great choice for "engergy efficent homes" . I guess if you disagree do call them, challange their data with your own ASTM 2558 lab and field test along with a 20+ year history installing them. Let us know what the outcome is of that conversation. Until then, until you post some data, and not narratives, please do not get offended if I find the builds and manufactures data more creditable and your opinion of these so called 'issues' in error.

Posted By sailawayrb: Irrelevant and more rubbish.

Nice technical educated response to the builders and manufactures data posted, I don't even think you took the time to read before the lame response. I have no idea how you get by the MODS continuing to promote your site and services by continuously bashing good builders, labs, manufactures, members that you claim "do not have the ability to understand", etc....The irony is you don't get it, you don't have the data from builds and/or labs to show. You DO have good writing skills and the ability to attempt to fool people with big words like BTU's, heat rates, etc, and a creative way to put values and generalities into word databased BS! I can only imagne your calculators that you can not show have been calibrated to any builds, manufacturing material data, national climates, or industry controlled test data. I enjoy reading your "bottom of the barrel rubbish"!! as I do a fiction novel. Here again, I'll take the noted blower door test and manufactures data over your rubbish any day of the week.

Until either of you post data to proove the RUMFORD manufactures and builder's blower door test and installation data inaccurate there is nothing more to discuss, a waste of time. Being right is not determined by a vote.

Posted By Bob I on 18 Jun 2014 01:13 PM
the issue I have with masonry heaters is simply that they continue to radiate heat after the fire goes out - that is their stated advantage. in a superinsulated house requiring very little added heat, this would likely lead to overheating with no way to stop the heat.

I agree with you on putting a fireplace in such a building, but if one does it, a chimney top damper combined with an insulated, gasketed removeable door covering the firebox does help keep air infiltration at a minimum. One also needs a direct air supply to the FP in order to use it.

Agree, it does not take a rocket mass scientist to figure out a mass heater in a high mass room in high desert heat will not work and is not a one size fits all application. For fast on and off heat the RUMFORD radiation heater low insulated mass storage heater makes PERFECT sense and has the sealing requirements you mentioned. Nice thing here is you see this without having to go through extensive math and theory or calculators just to come up with a mass heater solution. Kudos to you for your insight ;)

Posted By jonr on 18 Jun 2014 02:42 PM

the issue I have with masonry heaters is simply that they continue to radiate heat after the fire goes out

The best place for thermal mass is in a water tank. Then you can run the water over the roof for radiant cooling or through a wood boiler for heating with wood.

Agree and in combination with solid mass walls and floor. Wouldn't it make sense to run cooling lines through the ceiling too? You did some research on that didn't ya?

I think folks are tired of your ignorant and angry responses. I certainly am and two word responses is about all you will be getting from me from here on out. Post your website so folks can see how wonderful your company is and what your customers think about your services.

Posted By sailawayrb on 19 Jun 2014 08:46 AM
I think folks are tired of your ignorant and angry responses. I certainly am and two word responses is about all you will be getting from me from here on out. Post your website so folks can see how wonderful your company is and what your customers think it.

I created this thread as a white paper review to keep opinions out, since I read of many of yours especially that do not point to credible tested feild or lab data like the white paper. Since then JR and others have posted links of HRV_ERVs I have read and posted snap shots for comments. I posted links and test, build data. If you are going to participate read the data and comment on it or yes, I will get annoyed! To often members post good white papers and links that get ignored and tainted by personal opinions or hidden sales agenda's I was wanting to keep off this thread.

Post your website so folks can see how wonderful your company is and what your customers think about your services. Until then sir, I consider you a BS artist and a loser, just like I consider Jonr.

I want to thank Jonr for his post, the research and links he provided. As you can and will see I am not the only one that appreciates it.

Since the question of “what wonderful things” I and our company do is still standing I’ll answer it with a disclaimer, I’m not out here to promote our company. Excuse the website we are struggling to find the time to work on it, it does not provide us with much business. We have more work than we can handle by local word of mouth marketing. We have 6 employees and provide around another 6 sub jobs to our local economy to do our part in reducing unemployment. We are hiring and growing fast with great success based on quality workmanship and design (me). We opened our doors 1.5 years ago as a result of my son being a top salesman in the storm damage industry working for someone else. It didn’t take him long to figure he could do better on his own while attending college to obtain a BA in Entrepreneurship. He takes credit for developing the storm restoration business, I have supported. I am working on our first testing and new construction prototype of innovative methods based on my background, hoping to break ground in the coming months.

I started as a construction worker at the age of 11 in 1971 helping my dad lay concrete footings in So Ca where I grew up and went to school, also as an auto and general aviation mechanic. After high school I took more of an interest in general aviation and became a licensed “Airframe and Power mechanic”. Worked on turbine engines two years went back to college to get my degree in Aerospace at age 24. I found it more of a challenge and rewarding than civil and the pay was better. Today, I take credit for supplying our troops with some of the best weapons the world has to offer to keep our country America safe, starting with the design and build of the B2 stealth bomber in 1984, F-18, lately F-35 stealth fighter, in 2013 the HVAC system for the new “Scorpion Fighter”, new jets you all fly on like Boeing 787 Dreamliner I helped develop the grahite composite technology as a DE/ME. That is why I said in the OP my HVAC experience comes from another industry. I am well versed in three industries, I am trying to revive and update my memory of this one. I consulted The Scorpion as a sub-contractor short assignment for the first quarter of 2013 then took the rest of the year off working on our company. I accepted a contract assignment in 2014, MI four months ago in one of the biggest test facilities in the world to gain more insight with hot box testing, Wind and Hail damage, seismic shaker tables, fire, endurance and sustainability, fungi, to name a few. In many US states I designed and built for the world class manufacturing industry the past 30 years in the disciplines of structures, mechanical, and electrical systems.

I ended my contract at the lab as of this Friday. Next Monday I leave for Chicago to pick up at some bags of hemp. I am behind some legislation to legalize it as a building material for affordable housing. On my way home to KS I plan on stopping in NE home of the “Straw Bale Home” and “load Bearing wall” to Pilger, NE Twin Tornado's  EF4 that killed two, a 5 year old in a mobile home and critically injuring 16,  and to volunteer for disaster relieve efforts. I also plan to analyze the destruction, collect data for my design and development effort of “Affordable Tornado Proof Green Homes” that save lives. I believe hemp has just legalized in NE and the first harvest is soon. We seem to be seeing lives lost more and more in tornado alley as a result of two consecutive years in 2011/2013 massive EF 5 destruction in Moore, OK south of us, we got hit in 2012 EF4, Greenburg EF5, Joplin, Mo EF5…killing many!! My vision is to first and foremost save lives, and quickly respond to the homeless enabling and empowering them to build affordable homes.

If anyone is interested in meeting me in Pilger I will be there Tuesday July 2^nd or in becoming part of my Midwest disaster relieve network please PM me. Or continue to support the thread in developing low cost heating and cooling for the needy and poor.

Hope I answered your questions Sali if not PM me.  Let's keep the thread on topic now please.

Thanks, Terry

Hard to get your mind around when 5 year old kids die isn't it? Need your help God!

The mobile home factory built high carbon foot print profit industry needs to die instead of our children!....Paramount Construction, LLC mission statement even if we end up DIRT poor! We are founded in Christ whom made this country, He has our back, faith we have.

I know we can do better and yes I am angry! You people have designed structures that kills our kids and made your money... Now I will do something about that and make no profit for the sake of humanity.

My biggest hope and mission is to put all you out of business and design non-profit homes people can be safe in and afford! it will take less than 5 years.