MRCOOL

MRCOOL is a gas tankless water heater from MRCOOL rated 5.7 GPM at a 0.95 UEF.

Efficiency
Uniform Energy Factor (UEF) 0.95
Annual gas use (natural gas) 175 therms/yr
Recovery efficiency 0.99 %
Annual propane use 191.25 gal/yr
General
Fuel Natural Gas
Capacity
Max flow rate 5.7 GPM
Draw pattern High
Minimum activation flow 0.6 GPM
Performance
Gas input rate 199 kBTU/h
Installation
Max current draw 1.3 A
Vent type Power Direct Vent
Vent size 2 / 3
Smart features
Smart / connected capable No
Dimensions
Height 26.8 in
Width 17.3 in
Depth 11 in
Certification
ENERGY STAR certified Yes

Real flow rate by climate

A tankless heater's usable flow depends on how far it must raise incoming water temperature. Sustained hot-water flow of the MRCOOL at common temperature rises (a typical shower uses about 2 GPM of mixed water):

Temperature rise Climate Sustained flow Simultaneous showers
45 °F Warm climate (~75 °F groundwater) 5.7 GPM 2
55 °F Mild climate (~65 °F groundwater) 5.7 GPM 2
70 °F Cold climate (~50 °F groundwater) 5.4 GPM 2
77 °F DOE test condition 4.9 GPM 2

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Frequently asked questions

Is the MRCOOL ENERGY STAR certified?

Yes, the MRCOOL holds a current ENERGY STAR certification for water heating efficiency (UEF 0.95).

How much does the MRCOOL cost to run per year?

About $254 per year at national average energy rates, based on its certified annual energy use under the DOE test draw pattern. Your rate and usage change this figure.

What venting does the MRCOOL use?

The MRCOOL uses Power Direct Vent venting with 2 / 3 in vent connections. Matching the existing vent type is usually the cheapest replacement path.

Is the MRCOOL a smart water heater?

No, the MRCOOL is not connected-capable — it has no app connectivity or demand-response support.

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