Although you get nearly the same amount of heat out of a kilo of hardwood as you do a kilo of softwood, hardwood is denser so would need less logs than softwood, hence softwood is usually cheaper to buy.
Lots of people believe that you should not burn conifer as these contain sap/resins which tar up the chimney or flue. This is largely untrue. The more likely cause of a chimney or flue blockage is by burning unseasoned wood as the high water content combines with other gases and particles and as the fire isn't burning hot because of the inefficiencies of burning wet logs, the condensation forms a creosote substance which hardens as it cools to form a tar lining. The other problem is that the condensation is acidic and will corode the inner liner of a flue. It is important for anyone burning logs to have their chimneys/flues swept regularly by a suitably qualified person to ensure it maintains safe and unrestricted.
So, the importance is not really the species - more the quality! Softwood is great for getting a fire going so it has its place when buring logs. The exception is for those people burning on an open fire, as that some species of wood tend to spit making species choice as important as the quality. This happens not just with conifer but also some hardwoods - notably horse chestnut, sweet chestnut and willow.
Other factors to carefully consider when purchasing your logs, is to clarify exactly what volume of logs you are buying. Our loads are always measured to ensure you get 1m3 of loose logs. I am amazed when new clients phone up and ask for a price for a 'load' - can you compare a shallow covering of logs in a large tipper van to a deep trailer load or a back of a pick up? We have experimented by putting the same amount of logs in different delivery vehicles/bags and you would be surprised how easy it is to give the impression that you are giving more logs, just by the type of vehicle or bag it is delivered in. Beware of buying logs in builders dumpy/1 ton bags as you appear to be getting a good amount but they only hold around 0.6-0.75 m3 and they do not allow moisture out so the logs can't dry out. Also remember that if you buy large logs (diameter more than length), you will get more air space in your load so maybe it might be worth buying smaller logs although you have to put more logs on the fire. It all depends on what is important to each client. At AG Tree Services we try to use as much of the tree as possible so you tend to get a good mixture of sizes from narrow branch wood to large split lots.
At AG Tree Services we strongly recommend you buy your logs well in advance of when they will be required (even the year before if possible) and store them in a log store or garage so that you can drive that moisture content right down giving you the most efficient burn and subsequently the best value for money.
Please feel free to call us on 01305 246573 or 07403 944331 if you would like to discuss any firewood or to place an order. All our logs are locally sourced from sustainable woodland work or tree surgery arisings, keeping the carbon footprint low and we tailer the size and species to the needs of each individual client.