Complex sentence: The rocket stove/Rocket mass heater can be used for cooking and for space heating and uses less wood than a traditional open fire, can burn small diameter material and produces less pollution which can be easily constructed from low-cost materials.
Split into simpler sentences: The rocket stove/Rocket mass heater can be used for cooking and for space heating. It uses less wood than a traditional open fire, can burn smaller diameter material, produces less pollution which can be easily constructed from low-cost materials.