How to Cut, Stack and Store Firewood

Experienced wood-burners have a few tried and tested methods for storing firewood that can prevent wood from rotting and dry it out efficiently. Choosing the right wood, and cutting, and splitting properly are also factors to take into consideration to prepare for the next season.

Firewood cut, split, and stacked to allow air circulation

When cutting wood in the forest look for dead trees first before cutting down and good healthy tree.
Make sure the tree has not rotted out, then cut into lengths appropriate for the fireplace or wood stove. 

Next, split larger logs in to pieces so that the interior wood is exposed to the air. Wood that has not been split will not dry out. Spitting wood is good exercise, but there are hand mechanical, electric, and gas-powered wood splitters available from $150 to $1,000 to make the job much easier!

The next step is to prepare a location for the stacked wood that is away from the house and open on both sides to allow for wind to blow through and dry the wood out. Place 2 x 4's or blocks on the ground lengthwise, then stack the wood loosely in rows. Avoid the temptation to tightly pack wood so it takes up less space. By not placing wood directly on the ground it won’t rot out.

Place rebar in the ground vertically or other support at each end of the stack to hold the wood in place. Cover with a tarp or lean-to to keep weather off of the top of the wood while allowing air to circulate through the ends.  If you use a lot of wood you may want to build a permanent structure with a roof. Let wood dry for at least 6 -12 months before burning. Be sure to purchase or cut wood at least six months before needed for the season to make certain it is dried out. If purchasing wood from a firewood vendor, order very early in the spring or even place your spring order in the fall of the previous year it will be needed.

Wet wood at more than 20% moisture content uses a lot of energy and time to dry the wood out before it will burn. For this reason, an inexpensive moisture meter is a good investment. Bring pieces of wood indoors several days before burning and place then a couple of feet away from the side of the masonry heater to dry it out if necessary. The optimal moisture content is 15 - 20%. 

The Top-Down Burn Method: To start a fire, place two to three large logs on the bottom, then two to three medium sized logs on top of that, then very small pieces of wood, and finally kindling. Add a couple of pieces of Fatwood to the top and light the fatwood with a match. ( Dry Fatwood is the center part of the pine tree with high resin content and lights very easily). This is the top-down burn method which has been proven to be cleaner burning, emits less CO, and is longer lasting. 

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Marge Padgitt is the publisher of Wood-Fired Magazine and president of HearthMasters, Inc, in Kansas City, Missouri
woodfiredmag.com http:www.woodfiredmag.com

How Large An Area Will A Masonry Heater Heat?

By Doug Hargrave

At first glance this seems to be a simple question which should have an easy answer. In actuality the answer to this question is much more complicated. There are two factors that must be quantified in order to determine if a particular masonry heater design will heat a defined square foot area.  One factor, which is relatively easy to determine, is the maximum heat output of the masonry heater. The other factor, determining the heat load (loss) of a defined square foot area under the coldest conditions, is more difficult.

While it is difficult to make an accurate claim as to the amount of space a particular masonry heater design will heat, it is possible based on the amount of wood burned, to accurately predict its BTU output and to define its heat storage capacity.  On the other hand, determining the heat load of a home requires a heat loss calculation of the floors, walls and ceiling based on their insulation properties, a determination of the homes efficiency in terms of outside air infiltration and inside leaks, and finally the heat load must be adjusted to the heating degree days for the geographic location of the home.

The following question and responses recently appeared on the members chat forum for the Masonry Heater Association of North America.

Question:

What can you expect out of a masonry heater with (the home) insulation being average to slightly above average? It would be nice to know how many Btu’s or how many square feet a typical heater will take care of.

 

Respondent A

That is a loaded question, and you can get into a lot of trouble promising a customer to heat xx square feet. We have one heater heating a 2800 sq. ft. super-insulated house in a cold climate. An identical one was built in a milder climate, and is incapable of heating a 1000 sq. ft. "poorly insulated" house. "Insulated" is a misnomer, since leakiness is often a bigger factor than insulation. "Efficiency" would be a better term, or "low energy" or even better "low heating load". 
 
You are better off to quote the heat output of the heater, and leave it be the client's responsibility to determine how much of his heating load it will cover. You can also quote some magic voodoo stuff about radiant heat. While real, it is much harder to quantify.  The generally accepted maximum output of a large heater is 20,000 BTU/hr, or 6 kW. One of those cube shaped 220V shop heaters is about 5 kW, so imagine one of those blowing continuously.  To get 20,000 BTU/hr, you need to burn about 100 lbs of 20% moisture wood at 70% efficiency. Typically, that will be two 50 lb fires per day. If you try to build a heater larger than that, you really need to know what you are doing, or be guaranteed durability problems.  Some companies up the rating of their heaters by specifying 3 fires per day. So you'd get 20,000 BTU/hr with a 33 lb capacity firebox.

Respondent B

(Respondent A) is correct: The only thing you can safely guarantee is output. If the heater is planned as the major heat source, I ask people to provide heat loss statement to compare with heater's output. I also can give them rough assessment of heater's capabilities bases on the max output for a reasonably largest possible heater at 25000 Btu/hr, extreme cases, 30000btu hr, and on rule of thumb for heat loss per sq ft related to the estimated R-value of their outside walls. The numbers for this rule of thumb were given at least a couple of times in this forum in the past. Super insulated home (R30 walls +) will have heat loss of 10Btu per sq ft or less, while a century home without any insulation may be in 40-50 Btu per sq ft.

Respondent A (additional comments)

Super insulated home (R30 walls +) will have heat loss of 10Btu per sq ft or less, while a century home without any insulation may be in 40-50 Btu per sq ft.

Using this rule of thumb, for a 20,000 BTU/hr heater:  Super insulated house: 2,000 sq. ft.  Un-insulated century house: 400 sq. ft.  You also have to factor in location.  Ottawa Canada has 8,100 heating degree-days.  Vancouver has 4,700.  A house in Ottawa with 2,000 sq. ft. is equivalent to 3,500 sq. ft. in Vancouver or 1,150 sq. ft. in Fairbanks AK in terms of heating load.

Respondent C

Generally speaking more mass means more heat capacity. Not all houses are constructed equally or in the same geographic location and not everyone burns their heater the same. Also not all heaters are placed in a central location, so the buyer must be informed that the rating may be reduced based on location.  I always tell potential buyers that no matter what, "they will always have a zone of comfortable heat output" if the power goes out. 

 

Respondent D

To be on the safe side, it is a good idea to ask the home owner to have an energy audit done on their house.   These audits are not expensive and will show where the cold spots are in the house. On the blower test, the inspector can determine the square footage of air leaving the house through leaks and can show where the leaks are. This is money well spent and will have a lifetime of positive effects.

Respondent A: +Norbert Senf – Masonry Stove Builders, Shawville, Quebec

Respondent B: +Alex Chernov – Stovemaster, Caledon, Ontario

Respondent C: +Doug Hren – Masonry Heater Design House, Hickory Corners, Michigan

 

Respondent D: +Gary Hart – Aaron’s Ltd. Alternative Energy, High Ridge, Missouri