Custom builders generally provide extensive flexibility when it comes to selecting a furnace or air conditioner. An especially popular trend is hybrid heat technology that allows the system to automatically choose the most efficient fuel source given certain conditions and alternate between fuel sources as conditions change. The Hybrid Heat Dual Fuel system by Carrier is so energy-efficient that the cost to heat is less than with any gas furnace.
For existing homes, don’t rely on the home inspection to audit a home’s HVAC system. A qualified contractor can inspect the home and identify areas that might not be energy-efficient. He or she also will be able to provide insight into the system’s efficiency and whether you may want to consider negotiating a system upgrade in your purchase offer. For example, beginning in 2010, manufacturers will no longer be permitted to produce units that use R-22 (Freon) refrigerant; so, you should ask whether a system is Puron-refrigerant compatible.