Hot water is a basic requirement for any home, and choosing the right water heater can be a daunting task with the range of tank-based and tankless systems available in the market. However, tankless models such as propane tankless water heaters offer a number of advantages such as lower installation costs, high energy efficiency and the ability to be installed in places where a tank based water heater is not practical. These features not only save you money upfront but also in the long run.
Propane tankless water heaters provide hot water “on demand,” ensuring that there is no danger of running out of hot water and no energy wasted keeping water warm all day and night. This guide will help you understand what to look for when shopping for the best propane tankless water heater and why the models discussed here are considered among the best in the market.
How propane tankless water heaters work
A propane tankless water heater, also known as a demand-type or instantaneous water heater, is a type of water heating system that heats water as it flows through the unit, rather than storing it in a tank. It is powered by propane, which is a clean-burning and efficient fuel source that is readily available in many areas.
The way a propane tankless water heater works is by using a heat exchanger, which is a device that transfers heat from one fluid to another. When a hot water tap is turned on, cold water enters the unit and passes through the heat exchanger where it is heated by the burning propane. This allows for a constant supply of hot water without the need to wait for a storage tank to fill up. The heated water is then delivered to the tap at the desired temperature.
What are the advantages of propane tankless water heaters
One of the main advantages of a propane tankless water heater is its high energy efficiency. Because it only heats water as it is needed, there is no energy wasted keeping a tank of water warm. In addition, the heat exchanger is able to extract more heat from the propane than a traditional tank-based water heater, resulting in a higher efficiency rating. Here are some more benefits of propane tankless water heater over traditional water heater.
- Energy savings: They are an affordable option for energy savings as they do not constantly use energy to heat and reheat water, reducing standby heat loss and waste.
- Endless hot water supply: Tankless water heaters deliver a virtually endless supply of hot water, you don’t have to pay for heating and keeping stored water warm.
- Space-saving: The compact size of tankless water heaters saves roughly 12 square feet of floor space.
- On-demand heating: They heat water only when it’s needed, eliminating standby losses that occur in systems with hot water storage tanks.
- Cost-effective: On average, they save about £120 per year in energy costs compared with typical electric storage water heaters.
- Low CO2 emissions: They generate 50-60% lower CO2 emissions compared with electric water storage tank systems.
- Rebates: Propane tankless systems qualify for rebates, which can make them even more cost-effective.
- No leakage risk: Unlike with storage tank water heaters, you won’t have to worry about gallons of water spilling into your home if a leak occurs.
- Safety: Because the air supply and exhaust vents of a tankless water heater are sealed, carbon monoxide gas can’t leak into your home because of a back-drafting issue.
How Much Propane Does a Tankless Water Heater Use?
The amount of propane and corresponding cost for a propane tankless water heater depends on 3 key factors: the size of the tankless propane tank, the hot water generation, and the energy efficiency. The size of the unit, measured in gallons per minute (GPM) and British thermal units (BTU), will affect the propane consumption.
A larger unit with a higher GPM and BTU will use more propane than a smaller unit. The hot water generation, measured in how long the unit runs per day, will also affect the propane consumption. A unit that runs for longer periods of time will use more propane than a unit that runs for shorter periods. Finally, the energy efficiency, measured by the energy factor (EF) will affect the propane consumption, with more efficient units using less propane.
Generally, a typical propane tankless water heater producing 40,000 BTU per hour will consume about 1.5 gallons of propane per day. This calculation is based on the fact that one gallon of propane contains 91,452 Btus. However, the actual propane usage of your own appliances, including your tankless water heater, will depend on factors such as the size and efficiency of the appliance, how well it is matched to your space, the quality of the installation and the frequency of maintenance.
Based on these factors, the propane consumption and corresponding cost can vary widely. With prices ranging from around £150 for smaller units to over £2,000 for high-output models capable of supplying hot water to multiple fixtures at the same time. On average, the cost is around £800 per unit. However, it’s worth noting that propane gas-burning tankless water heaters have a lifespan of 20 years or more, which is longer than most storage tank water heaters and electric tankless water heaters. If you experience an average energy savings of £120 per year, the cost of the unit will pay for itself in about six or seven years, after which you can continue to save money on your hot water expenses.
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Factors to consider before buying a propane tankless water heater
When considering a propane tankless water heater, one important factor to consider is the size of the unit. A properly sized water heater will meet your household’s hot water needs while operating more efficiently. To determine the correct size, you need to consider the flow rate and temperature rise required for your specific needs.
To determine the flow rate, add up the flow rates of all the hot water fixtures you expect to use at the same time. For example, if you expect to run a hot water faucet with a flow rate of 0.75 gallons per minute and a shower head with a flow rate of 2.5 gallons per minute, you would need a demand water heater with a flow rate of at least 3.25 gallons per minute.
To determine the temperature rise, subtract the incoming water temperature from the desired output temperature. For most uses, a temperature rise of 70 degrees Fahrenheit is desired, but for some applications like dishwashers without internal heaters, a temperature rise of 90 degrees Fahrenheit may be needed.
Most propane tankless water heaters are rated for a variety of inlet temperatures and flow rates, and some models even have thermostatic controls that can adjust the output temperature based on the water flow rate and inlet temperature. It’s important to note that a water temperature of 140 degrees Fahrenheit can increase the risk of scalding.
When evaluating the energy efficiency of a propane tankless water heater, one important factor to consider is the energy factor (EF). The EF is a measure of the overall energy efficiency of the unit, based on the amount of hot water produced per unit of fuel consumed over a typical day. This includes factors such as recovery efficiency, standby losses, and cycling losses.
Note that a higher EF value does not always guarantee lower annual operating costs, especially when considering different fuel sources. Therefore, when selecting a water heater, it’s important to consider the energy factor in conjunction with other factors such as size, first hour rating, fuel type, and overall cost.
Cost is an important factor to consider when purchasing a propane tankless water heater. The cost of the unit can vary depending on factors such as size, energy efficiency, and features. When considering the cost of a propane tankless water heater, it is important to evaluate not just the upfront cost of the unit, but also the long-term cost savings and benefits that it can provide.