The expense here can be divided into two category. One, is the price of the heater itself and the other is the cost of running the heater. From both these aspect, I can confidently tell you that greenhouse heaters are quite inexpensive compared to gas heaters. As for the price of the unit, greenhouse heaters are used all over the world and it’s a common practice. So, they come in pretty cheap and no matter what they cost, they are usually worth investing into. Then comes the running cost, which is again fairly low because greenhouse heaters are usually that powerful compared to heaters used at home.