Kitchen Gas Appliances - gas vs electric HW heater

My 15 yr old propane hw heater is working fine but I know it is on borrowed time. From an energy efficiency perspective, should I consider electric? Electricity is more expensive than propane (at least in my area) per unit of heat, but with electricity, all the heat goes into heating the water whereas with propane, significant heat goes up the flue. Does anyone know how much of the propane combustion heat is typically lost in the flue gas?

I'm not worried about heat losses through the tank itself because I assume they will be the same for electric and propane and/or can be kept to a minimum with additional insulation.

Hello artbuc. Welcome into my Gas Appliances topic.

If the existing unit is gas, it is less expensive to operate it than electric, the gas is already there, energy efficiency on new units is very high. Not much heat loss in the venting.

Electric heaters require 240 volts, hard wiring, etc. The gas set up is already there. Less money for operational costs, quick easy replacement, etc. Most houses with electric units convert from electric to gas.

Difficult to offer professional advice but easy to offer opinions. Everyone will offer theirs. The choice of course is yours.

Thanks Sharp Advice. You say energy efficiency of new gas heaters is high. Can you give me a typical number? When I did a search, someone said efficiencies could be as high as 97%. I think the only way you can get this high is on a condensing unit. I don't believe they make hot water heaters with heat exchangers to condense water in the flue gas. So, I'm guessing efficiency would be more like 75-80%.

Running a 240 volt supply would only cost me about $15 in for wire.

Sharp Advice, I found the efficiency data I was looking for. It is on www.gamanet.org. "EnergyFactors" are listed for virtually all brands of hot water heaters, gas and electric. The Energy Factor is a total number incorporating all three types of heat loss: heating water ( this is where flue losses come in), stand-by losses and cycling losses. Gas typically runs .5 to .6 and electric runs .7 to .95. If you assume .58 for gas and .9 for electric, you will be burning one gal of propane for every 17.4 kw-hr of electricity. From there you must apply your local costs for elec and propane to determine which unit will cost less for fuel.

If running electricity isn't a problem, a heat-pump water heater might be worth looking at. They use significantly less electricity than the resistance type and supposedly cost less to operate than gas. They pump cool air to the surrounding area which may or may not be a problem. In warm climate areas they may provide additional cooling benefit. Their initial cost is somewhat higher. I would guess their lifespan is similar to a gas heater and less than a resistance electric heater. An additional consideration is that they may make some noise unlike a resistance electric heater which is nearly silent and a gas heater which only has the small noise of the burner.

Doug M.