No gas. We have a wood-burning stove in the lounge, as well as a fairly well-insulated house. We are in Cape Town, so don't have the extreme temps of the inland cities. No aircon. We have electric blankets in the beds, so don't use electric heaters. Yes, your comment re the costs of solar vs our usage is valid. We had recently put in a new copper-lined geyser (which we still have), so it was the costs of the panel plus some plumbing and fitting. I'd need to analyse what we would have got had we invested that money, relative to what we have saved. But we took the conscious decision to do it for ecological reasons, not primarily to save money.