Purchasing a Woodstove
With so many woodstoves on the market today, homeowners are faced
with a difficult decision in determining which unit will meet their needs. The
purchase and use of a woodstove requires a substantial financial investment.
One must also educate the occupants of the home of the potential safety
hazards the woodstove poses.
The first thing to consider when purchasing a woodstove is to determine the
heating needs to be fulfilled. The following questions should be kept in mind:
-
How much space will be heated?
-
How often will the woodstove be used?
-
What are the cost limits for the wood heat system?
-
Will very young children be present, or are there other significant
problems to consider?
-
What safety equipment will be needed and what is the cost?
-
Will a woodstove be economical when compared the present heating system?
- Should I buy a regular woodstove or pellet stove?
When determining the area to be heated by the stove,
consider that an undersized stove will not heat adequately. An oversized stove
may release too much heat, causing the operator to reduce the air supply into
the stove -- a practice that leads to safety and air pollution problems, as
well as to reduce efficiency and wasted dollars.
Determine what type of stove will be purchased and also its placement.
There are many woodstove types and hundreds of woodstove models from which a
stove buyer can choose. Even for a buyer who has systematically analyzed the
type of stove desired, the actual buying process can be frustrating. One
method of simplifying it is to select a knowledgeable and reliable woodstove
dealer. The following questions should be considered in selecting both the
right dealer and the right stove manufacturer:
-
Does the dealer carry the lines of several different manufactures so
that comparisons can be made?
-
Are the claims made by the stove dealer on a particular stove realistic?
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Can the dealer assist in locating and sizing the stove?
-
Can the dealer deliver and install the stove
-
Can the dealer repair each stove sold?
- Are replaceable parts, service manuals and warranties available?
A correctly located stove can circulate heated air into
the more heavily used areas of the house; however, the homeowner can
realistically estimate the extent of air circulation in the house.
A final consideration before purchase is whether or not the stove meets
local air quality regulations. As a rule of thumb, the more efficient the
stove, the less pollution it produces. Check with your local air pollution
control district to see if there are regulations covering how efficient your
stove must be.
According to the U.S. Environmental
Protection Agency (EPA), the use of wood as a residential heating fuel
contributes up to 50 percent of the polynuclear organic air pollutants, some
of which may be carcinogenic. During winter months, in areas where wood is the
principal heating fuel, woodstoves produce as much as 80 percent of these type
pollutants. Robert McCrillis of the EPA says, "...In the field, it's the
installation and how the stove is operated that has the largest effect on how
it performs. Public education on the correct use of a word-burning stove is
part of the current regulations." To meet federal clean air standards, some
areas are regulating the use of wood stoves and banning fireplaces in new
construction. In order to curb pollution, some communities allow only
installation of EPA-approved Phase II stoves, which combust the wood more
completely and are more efficient.
Once a woodstove is purchased and installed, notify your local building
department to conduct a final inspection to ensure that all safety
requirements are met prior to using the stove.
Fireplaces
Fireplaces are relatively inefficient devices for heating the
home. On the average, an operating open-masonry fireplace can have
efficiencies ranging up to 15 percent depending upon its type and operation.
However, if there is no fire and the damper is left open a fireplace can
actually have a "negative efficiency" as warm air from the house will escape
through the chimney. Some local air pollution control districts may not allow
new fireplace installations. Check with your district and/or local building
department before installing a new fireplace or upgrading a current one.
The following should be considered when seeking to improve fireplace
efficiency:
-
Dampers -- When the fireplace is not is use, the damper should be
in the closed position to prevent warm room air from being exhausted out
through the chimney.
-
Glass or Metal Doors or Heat Shields -- A glass or metal door, or
any noncombustible shield placed in front of the fireplace, will limit the
amount of warm room air leaving the house when the fireplace is not is use.
This is especially advantageous when allowing the fire to burn down for the
night, but the damper has to remain open to allow for venting of the smoke.
While the fireplace is in operation, the glass doors should remain open
since most of the heat produced by a fireplace is in the form of radian
heat. If they are closed, the glass will deflect radiant heat back into the
fireplace and reduce the heat output into the room. Closeable doors are nor
required for any new installation in California.
-
Replacing Fireplaces with Wood Stoves -- Another method of
increasing the efficiency of the fireplace is to install a woodstove in
front of it, and use the existing fireplace chimney as the exhaust for the
stove. Before such an installation, the fireplace and chimney should be
inspected, repaired and cleaned. Check with your local building department
and/or air pollution control district to see if a wood stove or insert is
allowed.
-
Installing a Fireplace Insert into a Fireplace -- Efficiency can
also be increased by installing a fireplace insert -- essentially a metal
woodstove that slides into the fireplace cavity. Again, the fireplace and
chimney should be inspected and cleaned prior to installation.
- Changes in Fireplace Design -- Circulation fireplaces have heat
circulation ducts built into the masonry fireplace and can circulate air
from the room around a metal firebox and out into the room. Some of these
units have fans to increase the flow of air and heat. These units are made
of metal and thus warm quickly and cool rapidly once the fire is
extinguished.
Remember -- to achieve the most energy efficiency from
fireplace and to ensure safety, it is important to have your fireplace and
chimney cleaned and inspected at least once a year.
Purchasing Firewood
Firewood can be purchased in several forms. Although there are a
variety of measuring units, firewood is normally sold by the cord, or a
fraction of a cord. The dimensions of a "standard cord" is a stack of wood
piled 8 feet long, 4 feet wide and 4 feet high. One will not get a full 128
cubic feet of firewood with a standard cord because of the airspace between
the pieces of the wood; the amount of wood in such a stack will depend upon
the size and straightness of the pieces, how they are split and how the wood
is stacked. Because of this, the total cubic feet in a cord can vary from 70
to 90 or more cubic feet.
The more services a wood dealer furnishes (such as splitting, delivering
and stacking) the more costly purchasing will be. The cost of firewood varies
with different geographical areas. Orders for the purchase and delivery of
firewood should be placed well in advance of the heating season. Wood
purchased during the peak periods is in more demand and becomes more
expensive. You will also want to purchase early to guarantee seasoning.
Seasoned wood has a higher heating value than green wood. In general, a
cord of green wood will weigh 70 to 100 percent more than seasoned wood.
Seasoning takes place until the moisture content in the wood reaches
equilibrium with the moisture in the surrounding air. Wood stacked outdoors
with good air circulation in a dry, sunny and open are for about six months
will be dry enough to support efficient combustion.
The time of year and the size of the wood all have a significant influence
on its drying rate. Complete drying is facilitated by the proper storing and
stacking of the firewood.
Cutting your own firewood is also an option; however, it requires an
initial investment of equipment and demands a working knowledge of cutting
wood. Permits may be obtained by contacting the United States Department of
Agriculture Forest Service or the California Department of Forestry and Fire
Protection (CDF).
The easiest and best fire, for either a stove or fireplace, is achieved by
using a mixture of both softwoods (pines, firs, etc.) and hardwoods, (oak,
eucalyptus, etc.) The softwoods facilitate starting the fire, and the
hardwoods provide for long burning and good "coaling" qualities. A bed of
ashes underneath the grate produces steady heat and aids in igniting new fuel
as it is added. The fire will continue burning if small amounts of wood are
added at regular intervals. In fact, more efficient combustion results from
burning small loads of wood with sufficient air than from burning large loads
with minimal air.
Firewood is best stored outside, under cover and close to the house for
easy access. It should be stacked on a supporting base (such as cement blocks,
pallets or wooden planks) to prevent drawing moisture from the ground, to
allow air to circulate, to reduce insect infestation and to reduce dirt
accumulation. End braces or stakes can be used to keep the wood pile from
collapsing; they can be built to measure accurately a standard cord.
Below is the average energy content of various species of wood.
Wood Heating and Weight Values
| Species |
Btu/Cord* |
Cord Weight (pounds) ** DRY |
Cord Weight (pounds) ** GREEN |
| Alder, Red |
18.4 - 19.5 |
2000 - 2600 |
3200 - 4100 |
| Ash |
24.5 - 26.0 |
2680 - 3450 |
4630 - 5460 |
| Aspen |
17.0 - 18.0 |
1860 - 2400 |
3020 - 3880 |
| Beech |
28.6 - 30.4 |
3100 - 4000 |
4890 - 6290 |
| Birch |
25.9 - 27.5 |
2840 - 3650 |
4630 - 5960 |
| Cedar, Incense |
17.8 - 20.1 |
1800 - 2350 |
3020 - 3880 |
| Cedar, Port Orford |
20.7 - 23.4 |
2100 - 2700 |
3400 - 4370 |
| Cherry |
22.3 - 23.7 |
2450 - 3150 |
4100 - 5275 |
| Chinquapin |
23.2 - 24.7 |
2580 - 3450 |
3670 - 4720 |
| Cottonwood |
15.8 - 16.8 |
1730 - 2225 |
2700 - 3475 |
| Dogwood |
28.6 - 30.4 |
3130 - 4025 |
5070 - 6520 |
| Douglas-Fir |
23.5 - 26.5 |
2400 - 3075 |
3930 - 5050 |
| Elm |
22.3 - 23.7 |
2450 - 3150 |
4070 - 5170 |
| Eucalyptus |
32.5 - 34.5 |
3550 - 4560 |
6470 - 7320 |
| Fir, Grand |
17.8 - 20.1 |
1800 - 2330 |
3020 - 3880 |
| Fir, Red |
18.3 - 20.6 |
1860 - 2400 |
3140 - 4040 |
| Fir, White |
18.8 - 21.1 |
1900 - 2450 |
3190 - 4100 |
| Hemlock, Western |
21.6 - 24.4 |
2200 - 2830 |
4460 - 5730 |
| Juniper, Western |
23.4 - 26.4 |
2400 - 3050 |
4225 - 5410 |
| Laurel, California |
24.6 - 26.1 |
2690 - 3450 |
4460 - 5730 |
| Locust, Black |
29.5 - 31.4 |
3230 - 4150 |
6030 - 7750 |
| Madrone |
29.1 - 30.9 |
3180 - 4086 |
5070 - 6520 |
| Magnolia |
22.3 - 23.7 |
2440 - 3140 |
4020 - 5170 |
| Maple, Big Leaf |
21.4 - 22.7 |
2350 - 3000 |
3840 - 4940 |
| Oak, Black |
25.8 - 27.4 |
2821 - 3625 |
4450 - 5725 |
| Oak, Live |
34.4 - 36.6 |
3766 - 4840 |
6120 - 7870 |
| Oak, White |
26.4 - 28.0 |
2880 - 3710 |
4890 - 6290 |
| Pine, Jeffery |
19.3 - 21.7 |
1960 - 2520 |
3320 - 4270 |
| Pine, Lodgepole |
19.7 - 22.3 |
2000 - 2580 |
3320 - 4270 |
| Pine, Ponderosa |
19.3 - 21.7 |
1960 - 2520 |
3370 - 4270 |
| Pine, Sugar |
17.3 - 19.6 |
1960 - 2270 |
2970 - 3820 |
| Redwood, Coast |
17.8 - 20.1 |
1810 - 2330 |
3140 - 4040 |
| Spruce, Sitka |
19.3 - 21.7 |
1960 - 2520 |
3190 - 4100 |
| Sweetgum (Liquidambar) |
20.6 - 21.9 |
2255 - 2900 |
4545 - 5840 |
| Sycamore |
21.9 - 23.3 |
2390 - 3080 |
4020 - 5170 |
| Tanoak |
25.9 - 27.5 |
2845 - 3650 |
4770 - 6070 |
| Walnut, Black |
24.5 - 26.0 |
2680 - 3450 |
4450 - 5725 |
| Western Red Cedar |
15.4 - 17.4 |
1570 - 2000 |
2700 - 3475 |
| Willow, Black |
17.5 - 18.6 |
1910 - 2450 |
3140 - 4040 |
|
| * British thermal unit (Btu) values based on specific
gravity of 80 cubic feet per cord. 8000 to 8500 Btu per pound for non
resinous woods. 8600 to 9700 Btu per pound for resinous woods.
** Weights:
Lower value of range assumes 70 cubic feet of wood per cord.
Higher value of range assumes 90 cubic feet of wood per cord.
Dry weight at 12 percent moisture content. Green weight at 40
to 60 percent moisture content. All moisture contents based on "wet" wood basis. |
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