How Much Propane Does a Tankless Water Heater Use?

A tankless water heater is a type of water heater that doesn’t use one large storage tank but rather uses gas to heat the hot water as it runs through.

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As opposed to storage tanks, tankless water heaters are known for their improved efficiency in providing hot water where you need it when you need it.

While the efficiency and reliability of these units make them more attractive to consumers, many people are curious how much propane a tankless water heater uses.

Tankless water heaters use both natural gas and propane to power the unit.

Propane is preferred for its convenience, lower price point, and ease of use when you want to take it somewhere with you on vacation or camping trips.

In most cases, a tankless gas water heater that uses propane will also have a small electric heating element in case the location you’re in doesn’t have access to a supply of natural gas or propane.

Estimated Propane Usage Depending Upon the Models of Tankless Heater

Micro-Boilers – 100,000 BTU/hr output

This is one of the smallest models that use about 6.6 CFH (cubic feet per hour) each hour. It has an input rating of 18,000 BTU/hr. So in one hour, this model will use 13.2 cubic feet or 432 cubic inches of propane gas.

Large Capacity Tankless Water Heaters – 150,000 BTU/hr output

This model is a larger unit that produces about 150,000 BTU an hour. It has an input rating of 28,000 BTU/hr so it uses 16 cubic feet or 528 cubic inches of gas each hour. In one hour this tankless water heater will use 2 gallons and 112 cubic inches or 14.4 cubic feet of gas.

Multi-Head Instantaneous Units – 200,000 BTU output

Here’s a multi-head instantaneous model with a capacity of 199,900 BTU. It uses 23,500 BTU/hr at the highest output so it will use 30 cubic feet or 900 cubic inches of propane gas in an hour. This translates to 12 gallons of propane per hour.

Instant-Flow Tankless Water Heater – 275,000BTU output

Here’s another multi-head instantaneous model with a capacity of 275,000 BTU. It has an input rating of 37,800 BTU/hr so it uses 42.5 cubic feet or 1,291 cubic inches of gas each hour. This tankless water heater produces 635 gallons per hour which are out to 19.7 gallons per minute or 2.2 gallons per minute.

Tankless Hybrid Water Heaters – 375,000 BTU output

This tankless hybrid water heater produces about 375,000 BTU and has an input rating of 53,500 BTU/hr so it uses 26 cubic feet or 792 cubic inches of gas each hour. The total capacity is 726,000 BTUs so in one hour this unit will use 16 gallons and 512 cubic inches of propane gas which works out to 27.2 cubic feet or 1 gallon and 28.8 cubic inches of propane gas per hour.

Integral Tank Instantaneous Direct Vent Water Heater- 425,725 BTU output

Here’s another tankless hybrid unit with an input rating of 51,000 BTU so it will use 42.5 cubic feet or 1,291 cubic inches of gas each hour. This is an integral tank model so the propane storage is built-in inside the unit. The capacity is 630,000 BTUs and in one hour this unit will use 22 gallons and 672 cubic inches of propane gas which works out to 33.4 cubic feet per hour or just shy of 1 gallon per minute.

FAQs

How to Calculate the Propane Usage of Tankless Thermometer?

In order to determine the propane usage of a tankless water heater, you must know how much gas it will use per minute. This information is available from the manufacturer and will be listed on the unit’s specifications sheet.

Once you have this figure, simply divide it by 60 since there are 60 minutes in one hour. A larger output will use more propane in a smaller amount of time while a lower output appliance might not use nearly as much over an extended period.

Do Tankless Water Heaters Use More Gas Than Regular Gas Water Heaters?

The answer is no, but here are some numbers for reference. A standard 40-gallon gas storage water heater has an input rating of 67,000 BTU so it will use 11 cubic feet or 316 cubic inches of gas each hour. This translates to 10 gallons or 38.2 cubic feet per hour which is less than half the capacity of these large capacity tankless models.

How Much Does a Tankless Water Heater Cost?

The answer to this question will not only depend on the retail price of the unit but also installation costs. Prices range from $700 to $4000 depending on the sizing, output, and features. Installing a tankless water heater involves pipes modifications so there may be additional charges associated with this process.

Conclusion

If you plan on using a tankless water heater for an entire house, you should be aware of the potential propane usage. A small apartment unit may only use 1 to 3 gallons per hour so the cost will not be as much as larger units. Using eco-friendly heating systems can help avoid high energy bills and contribute to protecting our planet’s resources.

Some users of tankless water heaters complain that they run out of hot water faster than with a tank model because the storage capacity of the smaller unit is less. This can be resolved by turning on fewer water appliances or getting more efficient ones. You can also reduce the temperature on the hot water heater.

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Marry Nigah

Hi, I’m a clinical psychologist and inclined towards best buying practices for home and kitchen things. Critical towards choosing the best product and honest with my feedback. I’m a seasoned writer having more than 4 years of experience in multiple niches as well.

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