RUF heat logs are made of 100% Birch Hardwood. They produce a nice burn of approx. 1 hour followed by up to 1.5 hours of hot "glow". The duration of burning will depend on the quantity loaded and burn intensity regulated by air inflow settings. Low moisture 7.1%, low ash 0.4%, and high heat value 4.7kWh/kg make these briquettes a great choice. Each briquette measures approximately 65mm x 90mm x 150mm (approx. 2.5 x 3.5 x 6 in.). Each 10kg pack contains 12 heat logs in a plastic bag. Recommended for smaller wood and multi-fuel stoves and log boilers. For larger appliances, we recommend our Nestro round wood briquettes due to the larger size of the individual briquette. More details about RUF heat logs can be found here. 

Ash kiln-dried logs are 25cm in length and Extra Dry - some logs 5% or less, all logs below 20%. Heating value is approx. 5.3kWh/kg. One of best woods for burning, it produces a steady flame and good heat output. Ash wood produces excellent heat, a nice flame and it lasts reasonably well. More details about Ash Kiln-Dried logs can be found here.