Will My Wood Gun Be Large Enough?

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gunderwood

New Member
Hearth Supporter
Jun 14, 2009
7
Franklin, Tennessee
I've sent a down payment to AHS to build an E140 Wood Gun. The simple BTU calculator at their site showed that the E140 would adequately heat my 3800 square foot house. After reading some of your responses to other questions I'm wondering if the unit is big enough. Maybe I should have sized up to the E-180. My house is 2 years old with R-19 insulation in the walls, totally bricked on the outside, 24 windows @ 12 to 16 square feet per unit, 9 wooden mahogany doors (280 square feet total), 10 foot ceilings downstairs @ 2500 square feet, 9 foot ceilings upstairs @ 1300 square feet, R-30 in the attic, crawlspace block insulated. I also want to heat my DHW. Our winters here in Franklin, Tennessee are fairly mild but I still spent $3400.00 on LP last winter and my wife felt cold all the time as we kept our thermostat at 65 to 66 degrees. We have lows in December/ January in the single digits but usually lows are in the upper teens to low twenties. I've got 12 chords of hickory ready for the upcoming winter. I just hope you guys/gals can help assure me that I'm making the right choice with the E-140 (140,000 BTU) or should I size up to the E-180 (180,000 BTU). AHS says it's not too late if I can let them know soon. Thank You
 
At about 100K BTU per gallon? At 90% efficiency that would put you at around 100 Million BTU per year. Probably around 700 K BTU per day, or 30K BTU per hour, double that to get your maximum BTU. 140K BTU looks to be plenty.

OTOH, are you planning on adding storage at some point? I am designing a system now based on a wood gun. I am planning on building a storage unit at some point.... If you have storage the bigger your burner the better- it just means you can blast the heat into storage that much quicker. Any outbuildings? Hot tub? Pool?

100 M BTU per year, with 8 cords of hickory..... hickory comes in at 27.7 million BTU per seasoned cord, the wood gun is ~85% efficient, so maybe 4-5 cords a year. Or course your wife will now turn the heat up, so plan on burning the whole pile this winter.

Welcome to the boiler room, BTW.

Andrew
 
Wow, Andrew, thanks for the stats on BTU's and the hickory conversion factors. I knew I was gonna like this site when I signed up.
No storage planned for now as I would like to see how everything performs this winter. Thanks again. I'm sure I'll have more questions when the boiler arrives. I'm working on the outdoor boiler room/shed with wood storage right now. A 14' x 24' building that will house the boiler. It's about 50 feet from the house and I should have it completed in about a month.
 
Based on the gallons of propane you used, and the climate in your location, I would say the 140 should be plenty big enough to handle your needs. You shouldn't have any problem at all keeping the thermostat where you want it.
 
If you put another r 20 cellulose insulation in your attic you are likely to get by with a Woodgun 100 instead of the 140. It won't be a hunge difference but enough to tip the scales. I live in S.E. Wisconsin and am going with a 100. I have a 2200 sq. ft. ranch 9' ceilings, 4 1/2" closed foamin the walls and at least r60 in the attic. I have plenty of windows but not as many as yours. My heat calcs are 64,000 btu per hr. @-10 f. The heat calcs were for 3" foam in the walls so I'm sure I'm good.
 
Yeah, That's a good idea about the added insulation overhead. When are you getting your 100?
 
I move ion Friday if it passes final inspection. After that I am going to get started in a month or so. I'm putting it outside though. I don't know exactly how but I think I'm going to make it look like an OWB. I don't know just how yet. I don't even know if I'm going to get carbon or stainless. I am going to e mail the dealer and hope the units went down some. A few month ago he said steel has come down so maybe better deals on the way. I hope so cause stainless was 8900 and carbon was 6700 dollars.
 
Prices may have come down a little. AHS discounted 10% during the month of May so my E140 Stainless was $8730.
 
After crunching the numbers, it looks to me like the E140 should be plenty. I think you'll find yourself wanting the storage (water) before the end of the season.
 
The WG 100 stainless was 9400 in February. If your 140 is 8700 dollars do you know what the 100 is going for now?
 
Based on your propane consumption, your heat loss is identical to mine. I use an EKO 25 (80,000 BTU/hr) with storage and it's fine. I wish I had a bit more storage and a larger firebox, but the heat output is plenty. You'll lose a bit being in an outbuilding, but you should be fine.
 
AHS offered a 10% discount in May so I got almost 1000.00 off. The E-100 lists for $8886.00. The E-140 $9698.00. I think they offer a 5% discount in June. Maybe they would honor the 10% discount (summer pricing?). I don't know. I'm not trying to price their product for them, just giving you the info that was given me.AHS's Tel # is 717.987.0099. They'll e-mail a price list and discount offers.
 
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