New indoor boiler needed Gasification or non gasification?

[jsab9191]

I am building a new 2500Sq. ft. two story home in Maine. The new technology of gasifcation has some appeal,
but the simplicity of the older systems sappealing as well. The house will be very well insulated .
My goal is to have a system that is easy to run and not always in need of modifications. I'm a long time wood burner and have good supply of dry wood. the chimney will be designed for the system. What are the go to systems that I must check out? Yes, Price does matter, I have a hard time justifying $10,000. wood boilers.

 

[peakbagger]

A few things first, the concept of well insulated 2500 square foot home really doesn't say much. If you build to Passivhaus standards, you barely need a wood stove. If you build to Pretty Good House standard you also don't need a large heating system, if you aren't familiar with the Pretty Good house concept look at this link http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/pretty-good-house. If you are building with standard construction, possibly 6" walls, good windows and insulation on the basement walls, that's the standard these days and then you need a larger heating system. The best way to go is to have someone do a heat load calculation on your proposed design and then pick a system to match it or decide you want to go more radical with your construction techniques.

Another reminder many insurance companies and banks will not insure or make a loan on a house with a wood boiler as the only heating source, they generally require a conventional heating method, oil propane gas or electric. There are wood/oil combo units but you are better off installing two flues and find a deal on a used oil boiler (keep an eye on uncle henrys)

The next issue to consider is your pricing. If you go with gasifier or non gasifier, you really need storage and many gasifier companies will not warranty an installation without storage. Storage and the required piping that goes with it is going to raise the cost of your installation most likely above the $10,000 level. $15,000 for the boiler, storage tank, controls and specialized valving is probably more reasonable for a DIY install. If you have to go cheap spend the money on storage, with a house your size you probably want a minimum of 500 gallons and possibly 1000 gallons and its lot easier to integrate that into the house build than try to install later. I use non a non pressurized tank from AST in Searsport Maine, but if you want to go with a pressurized used propane tank, make sure the welder who modifies it is experienced. Once you have priced out the storage consider buying a used wood boiler from someone on Uncle Henrys, there are good boilers frequently listed with the statement, purchaser must remove, if you have the skills and equipment to remove a 1000 pound plus boiler you can frequently negotiate the price down quite a bit. If you go that route you need to be able to inspect the unit thoroughly and perform a pressure test but pressurizing it with a pressure gauge and then letting it set for awhile to see if the gauge drops down.

The efficiency gains for a gasifier are mostly at part load, if the boiler is properly designed and running full out, a conventional boiler can get close to a gasifier. On the other hand, run at part load and the conventional wood boiler is going to eat wood and need frequent cleaning. With storage you run the boiler flat out so the gasifer is not as important. I have 30 year old Burnham wood boiler, definitely non gasifier. I have cleaned my chimney once in 10 years of running the wood boiler as my primary heat source. I burn dry wood, have a center interior chimney and run it flat out to charge my storage. I inspect the chimney yearly and it generally doesn't need cleaning but I did it once out of general principle. On the other hand my neighbor with a non gasifer Tarm burned partially dried wood with no storage and had to clean his chimney every 6 weeks, had multiple chimney fire plus burned out two liners after his tile flue self destructed in chimney fire.

Brands to look at for non gasifiers are Buderus and Biasi , Gasifers are Froling.

Good luck

 

[jsab9191]

Thanks Peakbagger, I appreciate the thought you put into your reply. I didn't recognize the need for additional storage, but can see now that should be a important part of the plan. Also thanks for the great links . The new house will be traditional framing with very good insulation(not super insulated) .

 

[dogwood]

Jsab9191, I just finished my first year of heating with a gasifier. We have a Tarm Solo Innova with a thousand gallons pressurized storage. We live in a 3000 square foot, 1-1/2 story Cape Cod style home which I built in 1990-91. In hindsight here's some things I could have done better and would have been better decisions economically, or in reducing the labor involved heating with wood.

We have exterior 2x8 walls downstairs. I used some then current super-insulation techniques to frame the house. As I could install it myself, I used pink fiberglass throughout the house to save on initial cost. In retrospect this was a mistake. The additional expense of spraying foam insulation would have more than paid for itself by reducing air infiltration. Using the best available insulating techniques upfront will save you considerable heating cost down the road, and/or labor to provide wood to burn. Work any additional upfront cost into your house payment and then subtract out your monthly heating bill savings, or labor and time for you to provide wood to heat your home.

As it is with our boiler in operation, our heating bill has gone from last year's $300 a month to zero dollars a month. We were paying $500 a month when propane was at $5 a gallon. Once you pay off the boiler, as we did, that money stays in your pocket from then on. It's no worse than a car payment that goes away when the car paid off. Get a quality boiler that will last you a long time.

The better your home is insulated and built, the lower your ongoing heating expense and/or wood usage is going to be. You only get one shot at building. It's very hard to go back and fix where you have skimped on insulation or super insulation building techniques, or invested in a cheaper boiler for that matter. If I could do it over, I'd use all the best current insulating techniques. I'd also be looking at the smaller Garn boiler which has its own storage, burns larger splits and has a much simpler installation. Or I'd look at the Froling for build quality and its lambda component. If you will be using forced hot air heat look at the Kuuma wood boiler website. I'd also use panel radiators for a water based system if I was building new instead of the water to air heat exchanger we currently have installed in our forced hot air furnace plenum.

Safety and decreased maintenance are also important too. A gasifier burns clean with little creosote or smoke, and significantly reduces wood usage. Drive down to Tarm Biomass in New Hampshire and check out the Froling and Tarms they have. These things cost money, but are not the place to save money on your mortgage. If you are building a 2500 square foot house you should consider a comparably good wood based heating system that will end up saving you lots of money or labor once its paid off. There are few components of your home that can be said of. Our propane bill ranged from $60 a month in 1991 up to $500 a month three years ago. Spread that amount over twenty-five years and it puts the upfront cost in proper perspective.

If you have the time, read as much on this site as you can manage to build up your knowledge base. I knew nothing about wood boilers, gasifiers or otherwise, when I started, although I had heated a previous home with an Ashley woodstove years back.

Best of luck,

Mike

 

[jsab9191]

Dogwood , Thanks for you perspective on insulation and boilers. I've considered the Tarm products but the system with storage and backup would be north of $25,000 installed. I have a difficult time seeing the return on investment . I realize heating oil and LP gas will increase in price in the future. I still can't make the numbers work with that kind of investment in equipment. I will continue to consider options , any further input is greatly appreciated.

 

[Bad LP]

Dogwood , Thanks for you perspective on insulation and boilers. I've considered the Tarm products but the system with storage and backup would be north of $25,000 installed. I have a difficult time seeing the return on investment . I realize heating oil and LP gas will increase in price in the future. I still can't make the numbers work with that kind of investment in equipment. I will continue to consider options , any further input is greatly appreciated.

I don't think it's fair to add in the full cost of the required heating system in order to get to 25K.

In my own case I have a 2500 foot home built 10 years ago. 2X6 walls, FG insulation, 2X12 vented roof with FG and 1" rigid. House has almost 27% glass no skylights.
Heat is a System 2000, indirect domestic HW, RFH in 1.5" gypcrete except in the bedrooms where it's FHWBB. Basement zone is a hot water Modine. Installed duct work is purely for central AC. Total cost was 30K

Looking at adding a wood boiler and tying it into the current boiler. Estimated cost for a Tarm FHG-L boiler, water storage and piping is still 15K. Not an insignificant number by any means. I also expect the Varm to be in the same price range. However, I don't believe that this new boiler add on makes it a 45K system because the initial system, even coming in at a cost higher than something much more simple was already required.

We also have a Jotul Rockland insert in the LR that we love and an old school VC Vigilant (that just replaced an old steel stove) in the basement but I miss those warm floors and spent a ton of money to get them because that is what I wanted.

When LP was costing us 700/month winter for a house used on a few weekends a month (due to the high cost of LP) the added cost of a wood boiler was a lot easier to justify. This year with LP costs being low plus having a much warmer than normal winter It's a hard pill to swallow. No matter how how I slice it, listen and learn from those here and elsewhere that 15K buys an awful lot of LP.

 

[peakbagger]

I took a hydronic course last year from John Siegenthaler who is a recognized heating "guru". His designs are optimized towards maximum efficiency and individual room control. He argues legitimately that the first cost is minimal compared to long term operating cost. Unfortunately if you go with his approach the up front cost will be steep. I would expect that if he is hired to design a system it is for a high end home or commercial facility. As a percentage of the overall cost, the HVAC cost drops to a lower percentage as the house or commercial building rises in cost. On the other hand for standard house being built by typical wood burner, I would expect first cost is significant.

Based on what I learned in the course, I have several upgrades that I could do to substantially improve my system efficiency, the primary upgrade is replace all my baseboard with low temperature emitters preferably with each room set up with a home run back to a multizone manifold. This would almost double my effective storage capacity. The next upgrade would be variable speed circulators and a new outdoor reset controller tied to a variable speed injection pump to run my circulating water temps way down. As I already have sunk cost in my system, doing the upgrade to emitters would be around 5K in pieces and parts and I expect the zone and controls upgrade would be another 5 k in pieces and parts. Much as I love a project, I would be hard pressed to spend anything on my heating system when I burn 3 to 4 cords a year at most and do the rest of my heating with minisplit which runs "for free" with extra solar from my PV system. I expect that the cost of the existing baseboard might be $1,500K so I expect the do it right approach would add around $8,500 to a barebones system. To someone building a house this $8,500 is probably something they would like to spend elsewhere.

 

[Bad LP]

Interesting Peakbagger,

I have 2 CI radiators that I would just love to use in one room or I will just bite the bullets and put panel radiators in there. I really like the look of these CI units. I also have plans to remove the BB heat in the 3 rooms that have them and would convert these to panel radiators.

All of this is tied into the fact that "if" I spend the money to utilize a wood boiler I want to be able to use the lower temp heat to it's maximum capacity. I say this knowing that the LP boiler would be moved down into a secondary source when the home is vacant.

 

[peakbagger]

Off topic somewhat but standard slant fin baseboards will work with lower temps but if sized for normal temps, you need a lot more length. Standard baseboards are convectors that heat the air and lower temps vastly reduces convective air flow. Panel radiators or good old Cast Iron radiators are radiant sources, they primarily heat the objects in the room, they can just be warm and still move the heat. John S also was a big advocate of wall or ceiling mount radiant panels behind the drywall but that is not something most folks would retrofit.

My storage can peak out at 185 degrees although I expect the tank stratifies so that the average is 175 deg F , my baseboards are basically undersized down around 135 deg F. With radiant panels I should be able to go down to 100 deg F roughly doubling my effective storage capacity. If I did do a retrofit I would size the new radiant panels for 120 deg F and use an outdoor reset control to adjust the loop temp to 120 deg F at the design low temp and then adjust the temp lower as it warms up. Of course my system is automatically set to switch over to oil at 140 deg F so the controls would be interesting.

 

[velvetfoot]

If you're building from scratch, how about forced air distribution with a high efficiency heat pump? You could have the benefit of air conditioning in the summer, which should add resale value. Maybe, if you could get enough rebates, use geothermal. Even if not, you would have enough electric load to put in solar, which still has pretty good rebates generally. Maybe add a wood furnace, gasifying or not, or just a wood stove. Lean towards open design on the house.

 

[TCaldwell]

Off topic somewhat but standard slant fin baseboards will work with lower temps but if sized for normal temps, you need a lot more length. Standard baseboards are convectors that heat the air and lower temps vastly reduces convective air flow. Panel radiators or good old Cast Iron radiators are radiant sources, they primarily heat the objects in the room, they can just be warm and still move the heat. John S also was a big advocate of wall or ceiling mount radiant panels behind the drywall but that is not something most folks would retrofit.

My storage can peak out at 185 degrees although I expect the tank stratifies so that the average is 175 deg F , my baseboards are basically undersized down around 135 deg F. With radiant panels I should be able to go down to 100 deg F roughly doubling my effective storage capacity. If I did do a retrofit I would size the new radiant panels for 120 deg F and use an outdoor reset control to adjust the loop temp to 120 deg F at the design low temp and then adjust the temp lower as it warms up. Of course my system is automatically set to switch over to oil at 140 deg F so the controls would be interesting.

Not to hijack this thread but Tekmar has odr Controlls that will stage 2 heat sources, handling the low temp switch over from wood to oil. It will do this as well for dwh, keeping track of run hrs for each stage. After approx 4 months of use I'm running the oil boiler about 3.5pct of the time for dwh, I was surprised how little the pct is. At first I was disappointed to hear the ob kick on but for the ability to manage both with a simple control approach I've accepted.

 

[woodsmaster]

If you're building from scratch, how about forced air distribution with a high efficiency heat pump? You could have the benefit of air conditioning in the summer, which should add resale value. Maybe, if you could get enough rebates, use geothermal. Even if not, you would have enough electric load to put in solar, which still has pretty good rebates generally. Maybe add a wood furnace, gasifying or not, or just a wood stove. Lean towards open design on the house.

Forced air ? Yuck

 

[mike van]

To get back to the original question - I had a non gasser add on boiler for 16 years, pretty sure I will always have the record here in town for non reported - not responded chimney fires - The constant cycling of the auto damper sending smoke up a cooling chimney is a recipe for disaster, burning into storage is the only way to go -

 

[maple1]

^^ That.

Storage can be a bigger gainer than going from non-gasser to gasser. Depending on the specific boiler. Anything with tubes for heat exchanging or multiple passes for heat exchanging or whatever else for good heat exchanging will see a world of difference with storage added. A boiler with poor heat exchanging (simple water jacket) - not quite as much.

 

[JohnDolz]

Off topic somewhat but standard slant fin baseboards will work with lower temps but if sized for normal temps, you need a lot more length. Standard baseboards are convectors that heat the air and lower temps vastly reduces convective air flow. Panel radiators or good old Cast Iron radiators are radiant sources, they primarily heat the objects in the room, they can just be warm and still move the heat. John S also was a big advocate of wall or ceiling mount radiant panels behind the drywall but that is not something most folks would retrofit.

My storage can peak out at 185 degrees although I expect the tank stratifies so that the average is 175 deg F , my baseboards are basically undersized down around 135 deg F. With radiant panels I should be able to go down to 100 deg F roughly doubling my effective storage capacity. If I did do a retrofit I would size the new radiant panels for 120 deg F and use an outdoor reset control to adjust the loop temp to 120 deg F at the design low temp and then adjust the temp lower as it warms up. Of course my system is automatically set to switch over to oil at 140 deg F so the controls would be interesting.

I have no idea if my house is overbuilt with slant board but I can share that I have standard slant fin baseboard and heat with low temperature water all the time (if I had to guess I would say my design temp is 105 - 120F most of the winter) and my house stays at 72F. This is accomplished by the circulators running basically nonstop. The challenge is if you try to have the heat turn down at night, recovering with Design Temp that low is nearly impossible. Fortunately my boiler has a control that allow Indoor Temperature Sensor to override ODR when I recover from setback. Once the house is toasty ODR takes back over and I go back to very low flow temps.

 

[mpilihp]

So I am also looking for a new wood boiler and had similar requirements, simple to run and inexpensive, I'm also in Maine. I have a conventional unit now so no saving to be found as I already burn virtually no oil. I do not want to have storage so I was looking at the Wood Gun for a gasser and Thermo-Contron for conventional unit. I decided to stay conventional because of the simple principal. I will say if you go conventional plan on installing a mechanical chimney cleaner because they do generate a lot of creosote.

The Wood Gun claims to not need storage and many owners on here agree and love them but some do not. Biggest issue I hear about them is leaking of smoke and causing house to smell. They have a powered draft and it. Is pushed out from the boiler causing smoke to leak if your pipe to the chimney is not perfectly sealed.. They also appear to have a huffing issue when starved for air sounding like cause when using too small of splits, is too much burning surface area. Good luck.

Phil

 

[woodsmaster]

So I am also looking for a new wood boiler and had similar requirements, simple to run and inexpensive, I'm also in Maine. I have a conventional unit now so no saving to be found as I already burn virtually no oil. I do not want to have storage so I was looking at the Wood Gun for a gasser and Thermo-Contron for conventional unit. I decided to stay conventional because of the simple principal. I will say if you go conventional plan on installing a mechanical chimney cleaner because they do generate a lot of creosote.

The Wood Gun claims to not need storage and many owners on here agree and love them but some do not. Biggest issue I hear about them is leaking of smoke and causing house to smell. They have a powered draft and it. Is pushed out from the boiler causing smoke to leak if your pipe to the chimney is not perfectly sealed.. They also appear to have a huffing issue when starved for air sounding like cause when using too small of splits, is too much burning surface area. Good luck.

Phil

Why would you not want storage ?

 

[maple1]

So I am also looking for a new wood boiler and had similar requirements, simple to run and inexpensive, I'm also in Maine. I have a conventional unit now so no saving to be found as I already burn virtually no oil. I do not want to have storage so I was looking at the Wood Gun for a gasser and Thermo-Contron for conventional unit. I decided to stay conventional because of the simple principal. I will say if you go conventional plan on installing a mechanical chimney cleaner because they do generate a lot of creosote.

The Wood Gun claims to not need storage and many owners on here agree and love them but some do not. Biggest issue I hear about them is leaking of smoke and causing house to smell. They have a powered draft and it. Is pushed out from the boiler causing smoke to leak if your pipe to the chimney is not perfectly sealed.. They also appear to have a huffing issue when starved for air sounding like cause when using too small of splits, is too much burning surface area. Good luck.

Phil

What are the gains you are hoping to see in switching from the New Yorker to the Thermo Control? I'm not sure it would be any simpler to run - and certainly not less expensive than just keeping what you have.

 

[mpilihp]

I'm hoping for several things, first I don't expect it to be any more complicated than the NYer and certainly simplier than a gasser.

The NYer was well used when I got it and the draft control on it is problematic. Hoping the Thermo unit will be more reliable, easier to maintain, safer and provide better heating.

As I said the bi metal draft control is a problem on the NYer, I've replaced it several times already and when we loose power it does shut down quick enough and over temping has ruined the bi metal unit.

Also the NYER water jacket is much smaller and the zone our bedroom is on is large and the bedroom is at the end. It doesn't get heated very well and having that zone heat more evenly will make my wife happy.

Lastly if it generates less creosote that will be a bonus...

The unit isn't alot of money, it's used with a 1 year warranty from the maker...

Phil

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