We have a gas furnace that needs replacing. I see incentives to replace gas heat with electric coming from small town governments in our area (Northwest Nebraska). Am I unwise to just replace our old gas heater with a new one?
It depends, you have about three or more options. First, you can replace your old gas furnace with a higher efficiency (90 - 95% AFUE)furnace and it will save you money this next winter. Second, you can replace your furnace while also installing a new heat pump. This option is called duel-fuel heating. Heat pumps requires some type of backup or emergency heating source. This backup heat can be either gas or electric resistance. This second option will provide you with the most efficient way to heat your home (but it will also be your largest investment cost).
Another thing to consider is the heating difference between gas furnaces and heat pumps. The output temperature of most new furnace is in the range of 110 - 120 degrees while a heat pump will only supply about 85 - 95 degree temperature. I know you might be thinking that this lower output temperature is a negative for heat pumps, but actually its a good thing. The closer the output temperature is to you thermostat set point, the more evenly your home will feel (i.e. it's a plus!). Think about it this way; do you know of anyone that wants the temperature inside their home to be more than 80 degrees? I don't know of anyone who does.
Originally posted by Midwest HVAC: It depends, you have about three or more options. First, you can replace your old gas furnace with a higher efficiency (90 - 95% AFUE)furnace and it will save you money this next winter. Second, you can replace your furnace while also installing a new heat pump. This option is called duel-fuel heating. Heat pumps requires some type of backup or emergency heating source. This backup heat can be either gas or electric resistance. This second option will provide you with the most efficient way to heat your home (but it will also be your largest investment cost).
Another thing to consider is the heating difference between gas furnaces and heat pumps. The output temperature of most new furnace is in the range of 110 - 120 degrees while a heat pump will only supply about 85 - 95 degree temperature. I know you might be thinking that this lower output temperature is a negative for heat pumps, but actually its a good thing. The closer the output temperature is to you thermostat set point, the more evenly your home will feel (i.e. it's a plus!). Think about it this way; do you know of anyone that wants the temperature inside their home to be more than 80 degrees? I don't know of anyone who does.
Hope this helps - GWC
As HVAC correctly points out a heat pump's supply temperature is lower than a furnace's. This means more air must be moved to put the same amount of heat into your home. More air may mean that the ducts for the original furnace are too small for the new heat pump. Or maybe they can handle the extra volume. But it needs to be checked out.
It wouldn't hurt to have the house load recalculated. Furnaces are often sized according the "bigger is better rule". You may have added insulation or new windows lowering the required load. The heat pump should not be matched to the size of the furnace, but sized to the actual home load. A oversize heat pump is less efficient, cycles more frequently leading to more maintenance and a shorter life. A good match to the load is important for optimum performance.
