Many people ask me about the difference in the cost of heating and cooling their homes with gas heating and electric cooling as opposed to heating and cooling with a heat pump. The following are some thoughts to help you make such a decision.
If you are contemplating switching to a heat pump, be aware that it will always be cheaper to heat your home with gas. Currently in this country we have at least a one-hundred-year supply of natural gas, so we’re not likely to run out any time soon.
Cooling is another matter. It cost about the same to cool with a heat pump as with a standard electric cooling unit, if the SEER rating (Seasonal Energy Efficiency Ratio) is the same. Note that the higher the SEER rating, the more efficient the device.
Furnaces are rated differently than air conditioning unit or heat pumps. Modern furnaces have a low-end rating of 80% and can have a high-end rating of 98%. This rating reflects the percentage of inputted fuel that is directly converted to useable heat. As with SEER, the higher the number, the more efficient the device.
Additional Pros and Cons of Heat Pump vs. Gas:
There are, of course, pros and cons associated with both types of systems. Heat pumps use electricity all the time. They, therefore, do not emit fumes that are harmful to the environment like a gas furnace. Heat pumps do, however, operate year-round. In other words, the outside unit (the heat pump) cools and heats the home. This creates much more ware on the heat pump than you would have on a standard air conditioning unit that only operates during the cooling season.
Heat pump air handlers (that portion of the system that is inside the home) require a 240-volt service directly from the electrical panel with minimum amperage draw of 40 amps for the smallest of these devices. Furnaces only require 120 volts and draw far less amperage, usually 5 amps, or so. This means that consideration must be given to the size of the electrical service coming into your home before you decide to install a heat pump. The cost to upgrade your electrical service may be a deterrent.
There are many applications where a heat pump is advantageous. For instance, if gas service is not available or installing gas service is especially costly. Some discerning home owners may also object esthetically to gas lines being obtrusive. I.E. up the outside of a home to supply and attic system. Flue penetrations through the roof may also be a consideration. Be aware, too, that second floor heating is handled a great deal from the main floor system due to heat rising. So, the heat pump may not operate as much as it would without that effect.
Just as with heat pumps, there are many considerations for gas furnaces. You might question how flue gases will be exhausted from the home. When side-wall venting is done for special furnaces that use PVC flues, ask how they should be located with relation to windows, doors, patios, or gathering areas. Also be aware that all chimneys cannot handle venting from the modern furnace that produces acidic flue gases, as all modern furnaces do. These gases will erode mortar in a brick chimney and require either a metal flue or a terracotta lined chimney.
There are, of course, many other considerations. Check with a heating and air conditioning professional for more input and feel free to post your questions for us to answer personally.