Heat Star Systems

7547 Mentor Ave., Ste. 312
Mentor, OH 44060
Ph: (440) 701-1031
Fax: (440) 918-1120

Electric Heater Sizing Information

This chart provides an easy reference to estimate the KW required to heat a tank. Heat losses from the surface of the solution and from the sides of the tank have been taken into account. Find the gallons at the left, move to the right of the column with the temperature at which you will be heating the solution. The number indicated here is the KW required to do the heating job. This KW figure assumes a heat-up period of six hours; for a twelve hour heat-up time simply divide the KW figure in half.

Gallons	100°F	110°F	120°F	130°F	140°F	150°F	160°F	170°F	180°F	190°F	200°F	210°F
50	1	1	2	2	2	2	2	3	3	4	4	5
100	2	2	3	3	3	4	4	5	6	6	8	8
200	4	4	5	6	6	7	8	9	10	11	12	14
300	6	6	7	8	9	10	12	14	15	16	18	20
400	8	8	9	10	12	14	16	18	20	21	24	25
500	9	10	12	13	15	18	20	24	24	27	30	32
600	11	12	15	16	18	21	24	28	30	32	36	38
700	13	14	17	18	21	24	28	32	36	38	42	44
800	15	16	19	21	24	28	32	36	40	44	48	52
900	17	18	21	24	27	32	38	40	44	48	54	58
1,000	18	21	24	27	30	36	40	44	48	54	58	64

Caution: This chart is for quick estimates only. Use the formula below for determining actual heat requirements.

Determining Specific Heating Requirements for Electric Heaters

Total cubic feet of tank. (Multiply the inside dimensions of the tank depth x width x length.)
Total gallons of solution. Multiply by 7.48 the cubic feet of the tank occupied by the solution. (If the solution is normally 6" below the top of the tank, allow this when figuring.)
Average ambient (room) temperature at which the tank will be used.
Temperature level at which solution is to be held.
Heat up time desired.

Losses due to agitation, ventilation, and work loads should be considered in calculating total KW requirements. After this information is known, the following calculations can be made:

A x 1.0* x 8.35** xB

3412 x C

D x E

Add the results of calculations. The total is the Kilowatt
requirement of the tank.

A	=	Total gallons of solution.
B	=	Difference from ambient temperature and desired solution temperature.
C	=	Desired heat-up time (hours).
D	=	Heat loss of tank—refer to charts.
E	=	Square feet of top of tank (multiply length x width).
*	=	Specific heat of water. Insert specific heat of your solution here.
**	=	Weight of water. Insert specific weight of your solution here.

Surface Losses in KWs from Open Hot Water Tank
with Mild Air Agitation or Ventilation (120) FPM

Tank Temperature	Surface Loss Factor	Tank Temperature	Surface Loss Factor	Tank Temperature	Sufrace Loss Factor
80°F	.03	130°F	.30	180°F	1.10
85°F	.05	135°F	.35	185°F	1.30
90°F	.07	140°F	.41	190°F	1.60
95°F	.09	145°F	.45	195°F	1.95
100°F	.11	150°F	.51	200°F	2.35
105°F	.13	155°F	.58	205°F	2.80
110°F	.15	160°F	.65	210°F	3.25
115°F	.18	165°F	.73	215°F
120°F	.21	170°F	.83	220°F
125°F	.25	175°F	.95

Surface Losses in KWs from Open Hot Water Tank

Tank Temperature	Surface Loss Factor	Tank Temperature	Surface Loss Factor	Tank Temperature	Sufrace Loss Factor
80°F	.03	130°F	.30	180°F	1.10
85°F	.05	135°F	.35	185°F	1.30
90°F	.07	140°F	.41	190°F	1.60
95°F	.09	145°F	.45	195°F	1.95
100°F	.11	150°F	.51	200°F	2.35
105°F	.13	155°F	.58	205°F	2.80
110°F	.15	160°F	.65	210°F	3.25
115°F	.18	165°F	.73	215°F
120°F	.21	170°F	.83	220°F
125°F	.25	175°F	.95

Electric Heater Sizing Information

Surface Losses in KWs from Open Hot Water Tank with Mild Air Agitation or Ventilation (120) FPM

Surface Losses in KWs from Open Hot Water Tank

Surface Losses in KWs from Open Hot Water Tank
with Mild Air Agitation or Ventilation (120) FPM