Heater Sizing; Selecting The Correct Size Heater; For A Swimming Pool; For A Spa Or Hot Tub - Hayward H150 Installation, Operation And Service Manual

SECTION 2. HEATER SIZING

Selecting the correct size heater:

Factors influencing heater sizing include pool/ spa size, aver-
age wind velocity, ambient temperature and desired increase in
temperature over ambient. A pool/spa in a warm area with little
or no wind will not require as large a heater as one in a cool,
windy location. Detailed sizing information is provided below.

For a swimming pool:

1. Determine pool's surface area in square feet. For indoor pool
installations divide the pool's surface area by 3.
Pool Surface Area:
Figure 1
2. Determine desired pool water temperature
(usually 78 -82°F).
3. Determine average air temperature of coldest month of use.
4. The temperature rise is the difference between
2 & 3.
New Figure 2 for Manual 1302704001 rev F, page 4
VEW 2/7/2013
Temp. Rise °F
New Figure 3 for Manual 1302704001 rev F, page 4
VEW 2/7/2013
Model
H400
H350
H300
H250
H210
H200
H150
4
Figure 2 - Recommended Heater Model
10°
Model
H150 1,385
H200 1,848
H210 1,988
H250 2,309
H300 2,771
H350 3,233
H400 3,695
Figure 3 - Recommended Heater Model
200 300 400
Time in Minutes to Raise Spa/Tub Temperature 30°F
9 14
11 16
12 19
15 22
17 26
19 28
25 37
5. Locate in Figure 2 the surface area equal to or just greater
than the pool's surface area and the temperature degree rise
and select the appropriate heater model.
Figure 2 is based on 3 1/2 MPH wind velocity and elevation of
up to 2,000 feet above sea level.
When not in use, keep pool covered to reduce heat loss,
chemical usage and dirt load on the filtering system.

For a spa or hot tub:

Determine spa capacity in gallons (surface area x average
depth x 7 1/2).
The reference table lists the time required in minutes to raise
the temperature of the spa/hot tub by 30°F. Locate in the table
below the spa/hot tub size in gallons equal to or just greater than
the spa/hot tub size in gallons. Select the desired time to raise
the spa/hot tub temperature 30°F, read to the left and select the
appropriate heater model.
This guide can be adjusted for other temperatures rises. For
example, if a 15°F increase in temperature is desired, simply
divide the time for 30°F rise by the ratio of 30/15 = 2.
!
NOTE: Heat losses and/or heat absorbed by spa walls
(such as concrete) or other objects will add to the heat-up time.
Spa sizing is based on an insulated and covered spa. Always
cover spa or hot tub when not in use to minimize heat loss and
evaporation.
15° 20°
Pool Surface Area in Square Feet
924 693
1,232 924
1,326 994
1,540 1,155
1,848 1,386
2,156 1,617
2,463 1,848
Spa/Hot Tub Size in Gallons
500 600
19 23 28
21 27 32
25 31 37
30 37 45
35 44 52
37 47 56
50 62 75
25° 30°
554 462
739 616
795 663
924 770
1,109 924
1,293 1,078
1,478 1,232 1,056
700 800 900
33 37 42
37 43 48
44 50 56
52 60 67
61 70 78
66 75 84
87 100 112
35°
396
528
568
660
792
924
1,000
47
54
62
75
87
94
125