Pool Heater World Selection Guide

Heater Selection Guide

POOL SIZING

SPA SIZING

Determine your Pool's Surface Area

Determine your Spa Capacity in Gallons
(Surface Area x Average Depth x 71/2)


L x W	Circle Area: R x R x 3.14	Free Form Area: (W1 + W2) x L x 0.45
x	π ²	(+) x *0.45

In the Table below, locate the Area Equal to or sligtly Greater than your Pool Surface Area,
Read to the Left and Select the appropriate Heater.
Tables are based on a 31/2 MPH Wind Velocity and Elevation of up to 2000 Feet above Sea Level.

POOL HEATER SIZING CHART
Model Size	125	175	250	325	400
Temp. Diff.	Maximum Pool Surface Area (Sq.Ft.)
15° F	667	933	1333	1733	2133
20° F	500	700	1000	1300	1600
25° F	400	560	800	1040	1280
30° F	333	467	687	867	1067
35° F	286	400	571	743	914
Example: A rectangular pool, 40 feet x 20 feet with desired temperature rise of 25°F: 40 x 20 = 800 Sq.Ft. Surface Area, The recommended Heater is 250.

Let's go check on HAYWARD HEATERS

Let's go check on LAARS HEATERS

This reference table list the time required in minutes to raise the temperature of the Spa / Hot Tub by 30° F. Average depth: Surface area (above): Gallons = This guide can be adjusted for other temperature rises. For example, if you desire a 15° F increase, simply divide the time for 30° F rise by the 15° F increase (30/15 = 2)
SPA HEATER SIZING CHART
Model Size	125	175	250	325	400
Spa Size (Gal.)	Time to Heat Spa 30° F (Minutes)
200	30	21	15	12	9
400	60	43	30	23	19
600	90	64	45	35	28
800	120	86	60	46	37
1000	150	107	75	58	47
Example: To heat a 400 Gallons Spa 30° F in 30 minutes, The recommended Heater is 250. Note: Heat loss / Heat absorbed by Spa walls or other objects will add to heat-up time. Always cover your Spa or Hot Tub when not in use to minimize Heat loss and Evaporation.