What every best Furnaces has:
- The proper AFUE rating.
- Two stage valves.
- A programmable thermostat.
Although gas-fired furnaces and boilers are by far the most common type of home heating system, oil furnaces remain popular in areas with limited access to natural gas. As of May 1, 2013, the minimum annual fuel utilization efficiency (AFUE) for newly installed non-weatherized oil furnaces is 83 percent; weatherized furnace regulations took effect in January 2015 requiring a minimum AFUE of 78 percent.
Oil-fired furnaces have AFUE ratings than gas furnaces on average, although some models can achieve an AFUE of 95 percent. If you have an older oil furnace in your home, replacing it with a higher efficiency model will result in lower fuel costs and fewer carbon emissions than an older, less energy efficient oil furnace. It's estimated that upgrading an older 56 percent AFUE oil furnace to a 90 percent AFUE furnace will reduce CO2 emissions by 2.5 tons per year.
One big downside to oil-fired furnaces is the volatile price of oil versus natural gas, though a higher-efficiency furnace will at least use less oil, cushioning the shock when prices go up. Tax rebates or credits may be available from state governments or utility companies in some areas. For a complete, state-by-state list of credits and rebates, visit the Database of State Incentives for Renewables & Efficiency (DSIRE) website.