Introducing the Lighthouse Greenhouse Heaters  Designed to provide a stable environment to protect plants against sudden temperature and humidity fluctuations, the heaters are available in 45w, 80w and 135w variations. Running costs are a major benefit - these heaters use less than 50w per foot which is similar to the levels of an ordinary light bulb and 25% less than most tube heaters. The range is ideal for the greenhouse and also suitable for use in grow rooms and grow tents