For an exact measure, a heating contractor can test your furnace's efficiency. Many utilities offer rebates to encourage consumers to buy higher-efficiency furnaces. This is the key to making an intelligent financial decision about whether or not to replace your existing furnace. You'll see how long it takes for the furnace to pay for itself. There is no magic formula for deciding what fuel is best except by determining what types of fuel are available locally and their current prices.
Electricity is the cleanest yet most expensive.
Local fuel prices can fluctuate from year to year. Your heating contractor or fuel supplier should tell you the average monthly operating cost of a proposed system. Warranties Warranties are worth considering as heating equipment becomes more computerized and complicated. Newer electronic components can be expensive to replace. In addition, limited access to the heating equipment can complicate routine maintenance and result in maintenance being deferred.