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TAKAGI FLASH T-K1 versus Storage Tank Water Heater

The Flash water heater, model T-K1, is an on demand, tankless gas water heater. This space saving, highly energy efficient water heater can deliver over 200 gallons of hot water per hour.

The Flash utilizes the latest in technological controls for efficient water heating. These include computer modulated gas valves, electronic temperature sensor, electronic water flow sensor, electronic ignition (no pilot burner), computerized safety devices and even pipe heaters to protect the unit when the temperature is near freezing. Because of these advance controls the Flash is compact, about the size of a small Pullman suitcase, yet 5 times more powerful than the average storage tank water heater. The Flash has a self modulating input rating of 37,000 to 165,000 Btu.

Flash with its durable design and rust resistant powdered coating is made to be installed outdoors also.

TAKAGI FLASH T-K1 versus Storage Tank Water Heater


Takagi Flash T-K1

Storage Tank Water Heater

First hour rate

216 Gal/Hr

135 Gal/Hr


2.2 cubic feet

Avg. 24 cubic feet


24.5″ (H) × 16.5″ (W) × 8.3″ (D)

Avg. 26.5″ (D) × 69″ (H)

Shipping Weight

65 lbs.

325 lbs.

Energy Factor

Natural Gas: 0.81 Propane: 0.84


Thermal Efficiency

Natural Gas: 82.3% Propane: 84.7%


Standby Heat Loss


Avg. 20%


4″ Diameter Outdoor Powered Vent

Draft hood

Freeze Prevention Devices



Computer Modulated Gas Valves



Self Monitoring Computerized Safety Devices



Pilot Burner



Electronic Flow Sensor



Powered Combustion



With a storage tank, you store 40-75 gallons of hot 140°F water 24 hours a day, 7 days a week though you only use hot water a couple times a day. The tank type heaters constantly lose heat through the flue and tank walls trying to maintain 140°F. The heater cycles on and off to maintain this temperature. This causes cracking of the exterior walls and sediment build up which will eventually cause your storage tank to leak. The storage tank is designed to wear out and be replaced in time. Also, the storage tank water heaters only have a limited amount of hot water and after that is gone you have to wait for the tank to get heated again.

The Flash heats the water only when there is a demand for hot water. Opening a hot water faucet, ignites the powerful burners and the computer monitors the water temperature and adjusts the burners according to the need. High demand, high heat. Low demand, low heat. With no tank to run out you get an endless supply of hot water. No tank to heat means no standby heat loss. The Flash provides a continuous flow of hot water and will never run out, but the flow rate is limited to the temperature that you set. With a self modulating input rating of 37,000 to 165,000 Btu's this unit can handle a small application like a bathroom faucet and can take care of large demand application like a washing machine or dishwasher. This heater is designed to give you the maximum amount of hot water. With the 140°F temperature setting, you will need to mix it with cold water to get the water temperature you desire.

For residential customer who pays $50.00/ month on natural gas for Domestic water heating (DHW) ONLY, we project average savings of 30% based on same usage pattern. (Best way to find DHW energy cost, is to look at Natural gas bill during summer without heating.)

With usage pattern the same, savings will be average 30%. Single person 55%, two people using tank 40%, three people 35%, four people 30%, five people 25%.

Based on: $50.00/month DHW gas bill, average 30% savings, you would save $15.00 month or $180.00 per year. If tankless Takagi costs $1500.00 installed, alternative tank type water heater costs $600.00 installed, the differential of tankless is $900.00. Payback is 5 years. Return On Investment 20%.