500 Year Vision

Take pleasure from walking lightly on this Earth

Heat from wood versus heat from a heatpump


If our heating need is on average 30 – 35 kw, what quantities of wood would we need to burn to achieve the same temperatures.

Now, this means delving into the territory of BTU’s and cords of wood… a little research is necessary: First off, BTU is the amount of energy needed to heat 1 pound of water by 1 degree farenheit. Being EU, it’s all rather un-metric for me. But, 1 kWh of electricity = 3,413 BTU.

Quantities. 1 cubic metre of wood (a stere) is equal to 0.276 cords.

1.0 gigajoule (GJ) = 109 joules = 0.948 million Btu = 239 million calories = 278 kWh

If we have 10 square metres of wood, this will provide 81.65 gj of heat (if pine and 20% moisture), which is 22698.7 kWh. If we were heating at 30 kWh, the wood would last for 30 days.

Electricity from Eon is provided us at 4.36kc per kWh (cheeky seeing as suppliers sell it for less than 1kc per kwh!). If we have a heat pump we qualify for a special electricity rate, yet to be determined.

To be continued…

posted under 2007, August, Elements, Heat, Summer

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