What Is The Difference between Propane (LPG) And Natural Gas Hot Water Heaters

Using Propane and natural gas for hot water heaters will definitely save you money...

People are always asking me this fundamental question. "How much can I save by converting from a propane storage heater to a tankless hot water natural gas heater?". My answer is and will always remain "a great deal" as you will see in the next few paragraphs.

Propane also known as LPG and natural gas are the two gases that are mainly used in various types of hot water heaters. Propane is a lot more expensive than natural gas and both the gases can be used for domestic whole house water heating.

The cost of the energy source for hot water heaters is very important bearing in mind that electricity generally is more expensive but in this section we will consider gas fired hot water heaters only.

The Energy factor ...

Gas tankless (on demand hot water heaters) and gas storage heaters have very different energy factors. Some gas hot water heaters can burn either natural gas or propane but generally they are constructed to run one or the other gaseous fuel.

What Is The Energy Factor When Heating Water?

What Is The First Hour Rating For Tankless And Storage Hot Water Heaters?

The energy factor is crucial and can help us calculate the amount of energy wasted. Cost of gas used as $ per Therm (1 Therm is = 100,000 BTU) obviously is very important. Average US cost per Therm in Wisconsin in February 2004 was as follows (ref Jim O'Neale energy analyst contact tel (608) 266-8971 ....

Natural gas $0.922 per Therm (100,000 BTU)

Propane or LPG $1.366 per Therm

Heating Oil (for comparison) $0.972 per Therm

Be aware that these prices change monthly.

The range and average Energy Factors for Propane and Natural Gas hot water tankless heaters are

Now lets just use the following example ....

Person A buys the most efficient Natural Gas tankless hot water heater and person B buys the least efficient Propane gas hot water tankless heater and they both use 65 gallons per day of hot water (152 Therms of gas at 100% efficiency)

Person A actually has to buy 152/0.85 = 178.8 Therms of Natural gas per year and spends $164.87 per year to heat hot water and Person B actually has to buy 152/0.64 = 237.5 Therms of Propane gas per year and spends $324.42 per year to heat hot water

Person A saves $159.55 per year on hot water heating bill by making the right purchasing decision. Stated differently it can be generally said that purchasing a low efficiency tankless hot water heater using propane will cost you double when compared to using a high efficiency Natural gas hot water tankless water heater.

Now lets do a similar exercise to discover what could be saved by going from a low efficiency storage hot water heater using Propane in Wisconsin to a high efficiency tankless hot water heater using Natural Gas in Wisconsin .... Use the values in the table below and again assume 65 gallons of hot water per day from both types of hot water heater

Yearly propane costs to heat hot water in storage heater would be $451 (energy factor 0.46 meaning 330 Therms of propane gas is needed for heating water at $1.366 per Therm of propane gas)

Yearly Natural Gas cost for tankless hot water heater would be $164.87 (see above calculation)

Conclusion .... changing from propane gas hot water storage heater to natural gas tankless hot water heater would bring a saving of about $286 per annum in Wisconsin. This is a very important saving.

The table below shows Energy factor difference between best and worst units for different types of tankless and storage tank hot water heaters. The table shows that tankless hot water heaters are actually more efficient than storage hot water heaters...

You can read a wide range ofwater usage articles. They discuss the use of water in the house and home ... topics covered include filters, heaters, softeners and water in the garden.