Water Heater Recovery Time

Estimate water-heater tank recovery time from volume, temperature rise, heater input, and efficiency.

Author

Prof. Hans Muller

Plumbing editorial contributor

German renewable energy engineer at TU Munich, pioneering grid-scale hydrogen storage solutions

Reviewed by

Prof. Zara Khan

Plumbing content reviewer

Pakistani-British education researcher at Cambridge, evaluating digital literacy programs in South Asian rural schools

Last updatedFebruary 22, 2026

PublishedFebruary 22, 2026

Reference Values

Browse 112 reference values with individual detail pages for quick lookup.

Browse all reference values

Water Heater Recovery Time Calculator

Estimate how long a heater needs to recover a storage tank after a temperature drop.

Estimated Recovery Time

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Reference Table

Use this complete table for quick lookup and internal linking to specific value pages.

Water Heater Recovery Time Reference
Scenario	Recovery Time	Delivered BTU/h
30 gal, 40°F rise, 30,000 BTU/h	25 min	24,000
30 gal, 40°F rise, 40,000 BTU/h	18.8 min	32,000
30 gal, 40°F rise, 50,000 BTU/h	15 min	40,000
30 gal, 40°F rise, 75,000 BTU/h	10 min	60,000
30 gal, 50°F rise, 30,000 BTU/h	31.3 min	24,000
30 gal, 50°F rise, 40,000 BTU/h	23.5 min	32,000
30 gal, 50°F rise, 50,000 BTU/h	18.8 min	40,000
30 gal, 50°F rise, 75,000 BTU/h	12.5 min	60,000
30 gal, 60°F rise, 30,000 BTU/h	37.5 min	24,000
30 gal, 60°F rise, 40,000 BTU/h	28.1 min	32,000
30 gal, 60°F rise, 50,000 BTU/h	22.5 min	40,000
30 gal, 60°F rise, 75,000 BTU/h	15 min	60,000
30 gal, 70°F rise, 30,000 BTU/h	43.8 min	24,000
30 gal, 70°F rise, 40,000 BTU/h	32.8 min	32,000
30 gal, 70°F rise, 50,000 BTU/h	26.3 min	40,000
30 gal, 70°F rise, 75,000 BTU/h	17.5 min	60,000
40 gal, 40°F rise, 30,000 BTU/h	33.4 min	24,000
40 gal, 40°F rise, 40,000 BTU/h	25 min	32,000
40 gal, 40°F rise, 50,000 BTU/h	20 min	40,000
40 gal, 40°F rise, 75,000 BTU/h	13.3 min	60,000
40 gal, 50°F rise, 30,000 BTU/h	41.7 min	24,000
40 gal, 50°F rise, 40,000 BTU/h	31.3 min	32,000
40 gal, 50°F rise, 50,000 BTU/h	25 min	40,000
40 gal, 50°F rise, 75,000 BTU/h	16.7 min	60,000
40 gal, 60°F rise, 30,000 BTU/h	50 min	24,000
40 gal, 60°F rise, 40,000 BTU/h	37.5 min	32,000
40 gal, 60°F rise, 50,000 BTU/h	30 min	40,000
40 gal, 60°F rise, 75,000 BTU/h	20 min	60,000
40 gal, 70°F rise, 30,000 BTU/h	58.4 min	24,000
40 gal, 70°F rise, 40,000 BTU/h	43.8 min	32,000
40 gal, 70°F rise, 50,000 BTU/h	35 min	40,000
40 gal, 70°F rise, 75,000 BTU/h	23.4 min	60,000
50 gal, 40°F rise, 30,000 BTU/h	41.7 min	24,000
50 gal, 40°F rise, 40,000 BTU/h	31.3 min	32,000
50 gal, 40°F rise, 50,000 BTU/h	25 min	40,000
50 gal, 40°F rise, 75,000 BTU/h	16.7 min	60,000
50 gal, 50°F rise, 30,000 BTU/h	52.1 min	24,000
50 gal, 50°F rise, 40,000 BTU/h	39.1 min	32,000
50 gal, 50°F rise, 50,000 BTU/h	31.3 min	40,000
50 gal, 50°F rise, 75,000 BTU/h	20.8 min	60,000
50 gal, 60°F rise, 30,000 BTU/h	62.6 min	24,000
50 gal, 60°F rise, 40,000 BTU/h	46.9 min	32,000
50 gal, 60°F rise, 50,000 BTU/h	37.5 min	40,000
50 gal, 60°F rise, 75,000 BTU/h	25 min	60,000
50 gal, 70°F rise, 30,000 BTU/h	73 min	24,000
50 gal, 70°F rise, 40,000 BTU/h	54.7 min	32,000
50 gal, 70°F rise, 50,000 BTU/h	43.8 min	40,000
50 gal, 70°F rise, 75,000 BTU/h	29.2 min	60,000
65 gal, 40°F rise, 30,000 BTU/h	54.2 min	24,000
65 gal, 40°F rise, 40,000 BTU/h	40.7 min	32,000
65 gal, 40°F rise, 50,000 BTU/h	32.5 min	40,000
65 gal, 40°F rise, 75,000 BTU/h	21.7 min	60,000
65 gal, 50°F rise, 30,000 BTU/h	67.8 min	24,000
65 gal, 50°F rise, 40,000 BTU/h	50.8 min	32,000
65 gal, 50°F rise, 50,000 BTU/h	40.7 min	40,000
65 gal, 50°F rise, 75,000 BTU/h	27.1 min	60,000
65 gal, 60°F rise, 30,000 BTU/h	81.3 min	24,000
65 gal, 60°F rise, 40,000 BTU/h	61 min	32,000
65 gal, 60°F rise, 50,000 BTU/h	48.8 min	40,000
65 gal, 60°F rise, 75,000 BTU/h	32.5 min	60,000
65 gal, 70°F rise, 30,000 BTU/h	94.9 min	24,000
65 gal, 70°F rise, 40,000 BTU/h	71.2 min	32,000
65 gal, 70°F rise, 50,000 BTU/h	56.9 min	40,000
65 gal, 70°F rise, 75,000 BTU/h	37.9 min	60,000
75 gal, 40°F rise, 30,000 BTU/h	62.6 min	24,000
75 gal, 40°F rise, 40,000 BTU/h	46.9 min	32,000
75 gal, 40°F rise, 50,000 BTU/h	37.5 min	40,000
75 gal, 40°F rise, 75,000 BTU/h	25 min	60,000
75 gal, 50°F rise, 30,000 BTU/h	78.2 min	24,000
75 gal, 50°F rise, 40,000 BTU/h	58.6 min	32,000
75 gal, 50°F rise, 50,000 BTU/h	46.9 min	40,000
75 gal, 50°F rise, 75,000 BTU/h	31.3 min	60,000
75 gal, 60°F rise, 30,000 BTU/h	93.8 min	24,000
75 gal, 60°F rise, 40,000 BTU/h	70.4 min	32,000
75 gal, 60°F rise, 50,000 BTU/h	56.3 min	40,000
75 gal, 60°F rise, 75,000 BTU/h	37.5 min	60,000
75 gal, 70°F rise, 30,000 BTU/h	109.5 min	24,000
75 gal, 70°F rise, 40,000 BTU/h	82.1 min	32,000
75 gal, 70°F rise, 50,000 BTU/h	65.7 min	40,000
75 gal, 70°F rise, 75,000 BTU/h	43.8 min	60,000
80 gal, 40°F rise, 30,000 BTU/h	66.7 min	24,000
80 gal, 40°F rise, 40,000 BTU/h	50 min	32,000
80 gal, 40°F rise, 50,000 BTU/h	40 min	40,000
80 gal, 40°F rise, 75,000 BTU/h	26.7 min	60,000
80 gal, 50°F rise, 30,000 BTU/h	83.4 min	24,000
80 gal, 50°F rise, 40,000 BTU/h	62.6 min	32,000
80 gal, 50°F rise, 50,000 BTU/h	50 min	40,000
80 gal, 50°F rise, 75,000 BTU/h	33.4 min	60,000
80 gal, 60°F rise, 30,000 BTU/h	100.1 min	24,000
80 gal, 60°F rise, 40,000 BTU/h	75.1 min	32,000
80 gal, 60°F rise, 50,000 BTU/h	60 min	40,000
80 gal, 60°F rise, 75,000 BTU/h	40 min	60,000
80 gal, 70°F rise, 30,000 BTU/h	116.8 min	24,000
80 gal, 70°F rise, 40,000 BTU/h	87.6 min	32,000
80 gal, 70°F rise, 50,000 BTU/h	70.1 min	40,000
80 gal, 70°F rise, 75,000 BTU/h	46.7 min	60,000
100 gal, 40°F rise, 30,000 BTU/h	83.4 min	24,000
100 gal, 40°F rise, 40,000 BTU/h	62.6 min	32,000
100 gal, 40°F rise, 50,000 BTU/h	50 min	40,000
100 gal, 40°F rise, 75,000 BTU/h	33.4 min	60,000
100 gal, 50°F rise, 30,000 BTU/h	104.3 min	24,000
100 gal, 50°F rise, 40,000 BTU/h	78.2 min	32,000
100 gal, 50°F rise, 50,000 BTU/h	62.6 min	40,000
100 gal, 50°F rise, 75,000 BTU/h	41.7 min	60,000
100 gal, 60°F rise, 30,000 BTU/h	125.1 min	24,000
100 gal, 60°F rise, 40,000 BTU/h	93.8 min	32,000
100 gal, 60°F rise, 50,000 BTU/h	75.1 min	40,000
100 gal, 60°F rise, 75,000 BTU/h	50 min	60,000
100 gal, 70°F rise, 30,000 BTU/h	146 min	24,000
100 gal, 70°F rise, 40,000 BTU/h	109.5 min	32,000
100 gal, 70°F rise, 50,000 BTU/h	87.6 min	40,000
100 gal, 70°F rise, 75,000 BTU/h	58.4 min	60,000

Frequently Asked Questions

Common questions about Water Heater Recovery Time, formulas, and typical use cases.

What is water-heater recovery time?

Recovery time is how long a heater takes to raise tank water from one temperature to another after drawdown.

How is recovery time estimated here?

The estimate uses required heating energy (gallons × 8.34 × ΔT) divided by delivered BTU/h, converted to minutes.

Why include efficiency in recovery calculations?

Not all input energy is transferred to water, so efficiency adjusts effective heating rate.

Does this model standby losses and stratification?

No. This is a simplified estimate; real systems may recover differently due to losses, burner control, and tank behavior.

Methodology and Review

This page combines a live calculator, precomputed reference values, and FAQ content from the same conversion definition to reduce mismatch between calculator output and lookup tables.

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For compliance-sensitive work, verify final values against project requirements, governing standards, and manufacturer documentation.