Fireplaces provide a cozy, romantic atmosphere and can save you money on your heating bill. Though, there are many kinds of wood to burn in your fireplace or wood stove, not all wood performs equally. Some types provide longer, cleaner burning than others—and are, therefore, a better option than other kinds of wood.
Well-seasoned (two to three years) hardwoods are the best for fireplaces. These include oak, cherry, maple, walnut and ash. Of these, seasoned oak is usually considered the best for burning in fireplaces & woodstoves.
Burning time frame:
Oak and other hardwoods burn for longer periods (several hours, usually) than softwoods (pine and other needle-bearing trees, for example).When you burn hardwoods in the evening, you may have a few embers left in the morning. If you burn softer woods, this is rarely the case.
Choose wood wisely:
Choose only hardwood that has been seasoned (aged) at least a year. Fresh wood has a lot of moisture content. Therefore, it will not burn as well and will create much more smoke. In addition to using hardwood, use only wood intended for use in a fireplace–never use treated wood (construction lumber, for example) in your fireplace. This wood may give off toxic fumes and burn too hot.
Creosote is a residue that, if built-up inside chimneys, can cause chimney fires. Too much moisture in the wood you burn, whether it is softwood or hardwood, can lead to a quick build-up of creosote in your chimney. This is another reason to only use aged, dry wood.
It is fine to start a fire with softwoods (using these as kindling) and then add hardwoods to the mix. It may be tempting to buy only softwoods as these are much cheaper than hardwood. If tempted, keep in mind that you'll go through a lot more softwoods than you would hardwoods (due to burning times). Don't take someone's word on the age of firewood. If it looks heavy, solid and green, it probably is. Aged wood feels a little lighter and sounds hollower because the moisture is gone.