Need help on designing wood boiler system for new home with EKO 40.

[Mattes10]

This is my first post, but I've been reading the forums here as a great resource for the past several weeks. I would like to get opinions on what would be the best setup for a wood boiler system in a new home I will be building next spring.

First a few details. The location in southern MN. The house will be ranch style, 2000 sq. ft. basement and 2000 sq. ft. upstairs, heating 4000 sq. ft. total. R20 walls and R50 ceiling insulation. I am purchasing a modular home. The home will have ductwork already in place for upstairs.

Here is what I know I want..........
1.) A EKO 40 or Biomass 40
2.) Around 1000 gallons of storage
3.) The wood boiler located in shed outside of house.

Now here is what I was originally thinking. Put in a propane gas furnace for the ducts that are already in place. Build a shed to store the boiler and some firewood. Run insulated lines to the house (trench,plastic, sprayed closed cell foam). Connect to storage tank and run to a forced air heat exchanger. Also run a heat exchanger to our hot water heater.

A few questions...
1.) I've been told the water for the heat exchanger needs to be at least 140 degrees for the forced air exchanger. Will I have any problems with obtaining this amount of heat for long period with a EKO 40 and 1000 gallon tank. Do I need pressurized storage for a air exchanger?

2.) It's been suggested to me to put radiant heat in the house, as this runs with water down to 95 degrees.
Does anyone here use a wood boiler with storage with radiant heat. If so, does it work well and would they recommend. I'm very interested in this, but there is definitely added cost to putting in the radiant system and I want to make sure it is worth the money and effort. At minimum I was thinking I should put the pex tubing in the concrete when we pour, so at least we could use for the basement down the road.

3.) Can the storage tank be located in the shed, or should that be in the basement?


Lastly, and most importantly, just give me your two cents on what you would do if you were in my situation. I'm just planning now, so nothing is set in stone. What would you suggest for heating with a wood boiler if your new house already had the ductwork for upstairs in place?

Any guidance is greatly appreciated. Thanks!

Scott

 

[NE WOOD BURNER]

I am purchasing a modular home. The home will have ductwork already in place for upstairs.

I would suggest talking with the modular home company. The duct work could be eliminated and plumbing can be installed at factory or at least stubbed in during construction.
Since this is new construction you are in the driver's seat.
I would suggest a grade entrance basement. install boiler and storage inside. I would prefer an internal chimney(usually chase can be constructed at modular company). Otherwise you need external chimney or sacrifice 2 closets to go internal.
In floor in very well insulated foundation. you may need oxygen barrier pex (refer to hearth threads for further info.)
If you do keep the FHA ductwork, make sure its installed with the possibility of utilizing a wood FHA furnace based on codes for locality.
If you can get your cord wood prepared so its dry when your ready to heat.

 

[Mattes10]

One thing I should have also mentioned, I really would like to have central AC, Minnesota is very hot and humid in the summer. Unless there are good alternatives to central AC, I will likely need to stick with the duct work. I've been using window AC's the past 20 years and I'm ready to be done with those.

 

[maple1]

I would fully evaluate the cost difference between forced air, and radiant.

If I was building new, the only thing that would have me even thinking ducting, was if I needed central a/c. Then even if a/c was in the picture, that could likely be handled by a mini-split. Along with most of my heating. I think around here, mini-splits are now the standard heating choice in new modulars.

 

[maple1]

And to add, if doing hydronic I would definitely do radiant/in-floor.

And if I was putting a boiler in a shed the shed would be big enough for my entire winters wood also.

And my storage would be in the house.

 

[flyingcow]

I agree, low temp rads, or staple up systems.

And to add, if doing hydronic I would definitely do radiant/in-floor.

And if I was putting a boiler in a shed the shed would be big enough for my entire winters wood also.

And my storage would be in the house.

And have a frig and tv in the shed boiler room, maybe even a card table...........

 

[Fred61]

Boiler with storage and radiant are the perfect partnership. With the insulation you described, assuming it is installed correctly, you may be able to batch burn and enjoy the convenience of firing the boiler on your schedule. I would recommend putting the storage in the basement if at all possible and reap the benefits of the heat loss. If the house is insulated well you'll actually be able to see/feel the benefits of the heat loss from storage. Insulation doesn't stop heat loss fro the tank. It just slows it down.

Forget the ductwork, install mini splits and run your own pex in the floor.

 

[1MoCast]

This thread is of particular interest to me as we are in nearly the same situation, just a little further ahead. We have roughly the same square feet ranch style an I am also leaning toward the EKO 40 and 1000 gallons of storage in a detached garage. We just moved in to the new place and I am finishing the touch-ups at the old house so I can start on the garage and boiler system.

I put pex in the whole basement slab over 2" of high-density Styrofoam. BTW, I feel the underfloor foam is key to a comfortable lower level whether you have radiant heat or not. It provides a thermal break from the 50° earth. The kids and I installed the 2000' of pex in an afternoon/evening. I used HeatLink oxygen barrier pex and bought at a wholesale house in your town. It was half the materials only price the plumber quoted me for the Uponor. Figure about $1/sq ft for insulation and about $0.70/sq ft covered the pex, manifold, staples and fittings.
We also put in-floor in our sunroom. We were able catch it on time and get the floor trusses reduced 2" so the floors were level with no ramps. Most of the main floor hydronic floors we looked at had a 1.5" ramp going into the bathrooms. I used a Schluter product called Bekotec... kind of a foam egg carton looking sheet that you snap the pex into. It was pretty slick. Covered it with about 1/2" of tile crete to make the tile height match the hickory. We found out too late that we probably could have gotten the floor trusses made so the ceramic areas were reduced as well. I would check into this for your new construction. I ended up putting under floor (staple up) under the 3 bathrooms and the mudroom. It sounds like I should expect only comfort, not really heating from the under floor. I also had to get another manifold for the under floor as it will likely need a higher operating temperature.
We have an LP furnace/ central AC. Ours has a low speed blower setting for continuous run and I asked them to upsize the return air duct in the lower level kitchenette. Hopefully that will circulate some of the LL heat upstairs.
I couldn't sacrifice the space in the basement for the tank so I plan that going in the future garage. I am hoping the waste heat from the boiler and storage will heat a little shop space for me.
The other thing I wished I would have done was to start splitting last year... I processed a couple cords last winter while the framing was being done, but not enough. It will be a shame to have to buy wood when I have 2 big piles of logs from clearing the site.
Good Luck

 

[Woodfarmer1]

First off why aren't you buying a garn, there made right in your state. I just mailed the check for mine today.
I have pex on top 4" styrofoam ship lap, under my 1600sf slab, another 1600sf laid between my floor joist with pink underneath. I have half the house with 20' sidewalls and a 12/12 pitch with lots of windows. Subfloor and engineered hickory which had a very difficult time trying to heat last winter, just too much cubic space. Hopefully With the garn I'll be able to run twice as much btu's as the empire put out.
The designer first designed in ducts for the main floor, I wanted rads and we settled on in floor, I'll let you know in january if the system works any better.

 

[jebatty]

I've been told the water for the heat exchanger needs to be at least 140 degrees for the forced air exchanger. Will I have any problems with obtaining this amount of heat for long period with a EKO 40 and 1000 gallon tank. Do I need pressurized storage for a air exchanger?

As best I know, this would be true, and maybe even higher temp. This somewhat limits the practicality of any wood heating system with storage because you will need to keep storage water temp delivered to the heat exchanger at 140F and above, while water to the in-floor will be quite usable down to about 100F. The difference is "loss" of about 1/2 of your storage usability.

With your Mankato location, I seriously would consider mini-splits to minimize your need for that 140F water for heating: cooling but also relatively inexpensive heat during the shoulder seasons, especially if you get a kwh rate break for off-peak or similar. I have a 1956 rambler with 1500 sq ft + 1500 sq feet basement, similar to you, and you should be able to easily heat with a 140,000 btuh boiler/1000 gal storage setup.

 

[Millwork]

Matts,

I am running a eko 40 with storage and radiant heat and it's awesome. If the temperature is below 20 degrees I run my infloor water temp At 130 with a delta t of about 8 degrees .

 

[sweetheat]

pellet or stick gasifier and storage with infloor radiant in basement, radiators 1st floor, all the insulation you can afford, your wood inside close by. good luck

 

[pbvermont]

If building new, build the house tight enough and so well-insulated that you don't even need wood heat. Mini-splits should then do lion's-share of everything (heating and cooling). If you need more heat….smallish wood-stove.
Central wood-heat is for people with leaky, old houses or badly built modern ones, or people that just like to see where their heat actually comes from.

 

[Tennman]

Obviously both EKO and BioMass are very good boilers. My greatest fear 6 years ago being one of the early BioMass owners was whether the boiler pressure vessel would rust thru, all other components are either the same as the EKO or replaceable (lots of ugly boiler rotting out stories back then). I'm glad I went to New Horizon to look at both, I chose the BioMass, no regret. Today I just might come home with an Attack if I was driving to West Virginia.

The root cellar in our old home is where the propane furnace is located making for very long duct runs. Worst room is the kitchen which is diagonally across a long crawl space (maybe 60-70' long). Outside temp determines what is the minimum water temp to keep that room acceptable. I don't know the air temp drop for that long duct, but obviously centralizing the blower to keep duct runs shorter will allow you to run down to lower water temps if your home is tight. If it was practical I'd retrofit to radiant, but where we live, we use AC more than heat. I'm certain your home will be FAR tighter (and smaller) than what we heat.

The interesting thing I've found this first season running storage is significantly lower water temps are keeping our home acceptable. I think it's because before without storage there was very little thermal mass in the system and the water temp was low was because the fire went out (like 3-4AM) and rapidly dropped with the fan running. Now the fan can run for long periods on water down into the 120's or lower and keep the house at 67F (our winter setting). So 1000 gals of storage has gotten us closer the lower temps offered by radiant, but probably still not as comfortable as if we had radiant. Basically I'm feeling heat pump like temps coming out of the ducts on the vents at the far runs and it's acceptable because the fan can run long times at these temps. The other benefit of storage is far more uniform interior temps. Before we had extreme temp fluctuations when a fire went out and long recovery times. I think because of storage our home has become a significant thermal mass itself.

Only hot water enters our home which is the only acceptable option for our daughter's allergies. Placing storage in the structure was not possible. My biggest regrets are not appreciating how much a game changer storage is and not going and visiting an operating gasification boiler. Seeing and hearing the roar will give you a data point on what a properly running gasification boiler looks like. You have lots of guys there within an hour driving distance of you. That visit will be invaluable. Also, if you can't process most of your wood to get nearly free fuel (except for your sweat) a pellet boiler would be one of my considerations. Welcome and you've found the right group. Hope you enjoy the research as much as I did.

 

[rkusek]

Wow Matte10 that's a lot of different responses. I can tell you R20 walls and R50 ceiling work pretty well in my 2008 home. I have 2000' main floor and 2000' walkout basement ranch layout. Because of steep grade the basement is above ground (framed) on 2 sides rather than just 1 and one of these faces north. I put in a standard heat pump with electric backup to satisfy the bank since we didn't have natural gas, didn't want propane, and definitely needed A/C too. I can't do pump & dump geothermal in my area which would have cost about the same as my old school heat pump. The return wells or grid layouts would be over $25,000 and then you are still dependent on electricity which could get more pricey down the road when they start banning the coal power plants. While the mini-splits may be ideal in some situations, I would be skeptical that it would cost quite a bit to outfit all the rooms needing heating/cooling. My wife would definitely frown at all the indoor heads and I would wonder how long they would last and not yellow, etc. Forced air does create more dust however, and she doesn't like that. We also have the built in humdifier and also run the little ones in each bedroom. Heat pump heat is lukewarm much like 105-120 degree water in my plenum HX when my boiler fire is almost out. Given your insulation and as long as your windows & rest of building envelope is tight I think the forced air with lower temp water should give good results. I actually run water through my HX until it drops to 89 degrees, then when the house cools a couple of degrees the HP tstat will take over. My second tstat that runs just the water circulator and blower is set 2 degrees higher using a resistance heat setting so it keeps it right at setting (no hysterisis). The bottom line the home always stays at 68 degrees until boiler water drops below 89. Our last home had a high efficiency gas furnace in a new 2 story and this HOT-COLD-HOT-COLD cylcle is why people complain about forced air. Whether it be lukewarm HP heat or 120 boiler water heat, I'm convinced this much more desirable than the HOLD-COLD-HOT-COLD performance of a typical FA setup. One caveat is good insulation, windows, and tight building envelope. I like your idea of having the boiler in a shed. I have too many toys in my barn now and wish I had gone that route plus no insurance/fire concerns. I would put the boiler, tanks(spray foam insulated), and room for at least a couple cords in the shed. Position the shed so you can stack wood next to it on the southern side for excellent drying during the summer. The HP actually heated our home exclusively during the '09/'10 winter and my highest bill was $257 if I remember correctly. The wood boiler actually doesn't make financial sense in my situation but I like the warm barn in the winter and have a little security should electric rates explode some day. Right now I am finishing the basement and contemplating whether the pex with plates on the main floor & radiant in some of the basement walls is worth it (~$3000). Your are probably looking at about 3 grand for materials to put pex in slab but I think it would be worthwhile long term.

 

[mr.fixit]

Not sure if you guys realize this but the original poster hasn't been seen since September.

 

[Tennman]

Obviously NOT Fixit! LOL.... Maybe I'll just recycle my post later. Funny... Oh well... writing in the morning is cathartic for me.... so not a total waste just talking to yourself.

 

[Woodfarmer1]

First off why aren't you buying a garn, there made right in your state. I just mailed the check for mine today.
I have pex on top 4" styrofoam ship lap, under my 1600sf slab, another 1600sf laid between my floor joist with pink underneath. I have half the house with 20' sidewalls and a 12/12 pitch with lots of windows. Subfloor and engineered hickory which had a very difficult time trying to heat last winter, just too much cubic space. Hopefully With the garn I'll be able to run twice as much btu's as the empire put out.
The designer first designed in ducts for the main floor, I wanted rads and we settled on in floor, I'll let you know in january if the system works any better.

Well I have tons of hot water and 8-12 hours burns.....but the in floor in my particular application can't do the job. This summer I'll have to install a couple low temp rads and then I should have heat, finally.