# Calculator by cuiliqing

VIEWS: 43 PAGES: 8

• pg 1
```									                              Water Heater Sizing Calculator

Example 3 Bedroom House

Cold Water Temperature:                                                                             67.0

Fixtures and Appliances:
Showers:                                                                                                3
Bath Faucets:                                                                                           3
Kitchen Faucet:                                                                                         1
Dishwasher:                                                                                             1
Washer                                                                                                  1
Bathtub:                                                                                                3
Roman Tub                                                                                               0
Multihead Body Spa Shower                               GPM:             0.0                            0

Peak GPM (99%):                                                                                       4.5

Primary Calculation:
Heater KW Requirement:                                                                 21.0 - 25.0
(Method 1:)

Alternate Method for Verification:
Heater KW Requirement:                                                                 23.0 - 27.0
(2.5-3.0 GPM@130°F)
(Method 2:)

This interactive online calculator is designed to assist trade professionals in creating a sizing estimate for
SEISCO tankless water heaters. The calculations herein are based on industry flow rate standards and
normal environmental usage factors. The data generated by the calculator is for illustrative use only. All
sizing should be reviewed by a trained professional and all applicable code and licensing requirements
must be considered. In using this calculator, the user agrees to take full responsibility for the output
customer service with any questions regarding proper sizing for an application.
Instructions:

1. Enter Average Groundwater temperature from map on tab 2

2. Use the calculator for each hot water zone individually. Enter the number of fixtures/appliances in each zone
(For most homes we recommend a single zone. For larger homes, we recommend grouping
nearby fixtures and appliances to shorten distances and reduce wait for hot water or alternatively
use a demand recirculation loop)

(Note: Assumes 1/2 restriction on Roman Tub Fill)

(Note: Estimates Peak GPM for 99% of all hot water draws. 1% will exceed this flow rate)

3. Method 1: Calculated Recommendation

4. Method 2: 2.5-3.0 GPM of 130 °F Water for Whole House
Groundwater Temperature
35       37       42   47   52   57   62   67   72   77
Midwestern Climate
Souttern Climate
Ground Water Temperature:                    80           75           70     65      60
Temperature Rise to 105°F:                   25           30           35     40      45
Model       BTU            KW            GPM          GPM          GPM    GPM     GPM
RA14           47,782         14.0           3.8          3.2          2.7    2.4     2.1
RA16           54,608         16.0           4.4          3.6          3.1    2.7     2.4
RA18           61,434         18.0           4.9          4.1          3.5    3.1     2.7
RA22           75,086         22.0           6.0          5.0          4.3    3.8     3.3
RA28           95,564         28.0           7.6          6.4          5.5    4.8     4.2
RA32          109,216         32.0           8.7          7.3          6.2    5.5     4.9
2XRA22        150,172         44.0          12.0         10.0          8.6    7.5     6.7
2XRA28        191,128         56.0          15.3         12.7         10.9    9.6     8.5
2XRA32        218,432         64.0          17.5         14.6         12.5   10.9     9.7

Heat and Boost Options:
RA22+Tank¹¹     90,445        26.5            7.2          6.0        5.2    4.5      4.0
RA28+Tank¹     110,923        32.5            8.9          7.4        6.3    5.5      4.9
RA32+Tank¹     124,575        36.5           10.0          8.3        7.1    6.2      5.5
¹ GPM Rate unlimited, listed rate is after tank is exhausted
Northern Climate          HUD
Midwestern Climate

55       50     48        45       40
50       55     57        60       65     77
GPM      GPM    GPM       GPM      GPM    GPM
1.9      1.7    1.7       1.6      1.5    1.2
2.2      2.0    1.9       1.8      1.7    1.4
2.5      2.2    2.2       2.0      1.9    1.6
3.0      2.7    2.6       2.5      2.3    2.0
3.8      3.5    3.4       3.2      2.9    2.5
4.4      4.0    3.8       3.6      3.4    2.8
6.0      5.5    5.3       5.0      4.6    3.9
7.6      7.0    6.7       6.4      5.9    5.0
8.7      7.9    7.7       7.3      6.7    5.7

3.6      3.3     3.2       3.0     2.8
4.4      4.0     3.9       3.7     3.4
5.0      4.5     4.4       4.2     3.8
Water Heater Sizing Calculator

Temperature Rise:                                                                                  90.0

Fixtures and Appliances:

Peak GPM (99%):                                                                                      1.0

Heater KW Requirement:                                                                             13.0

This interactive online calculator is designed to assist trade professionals in creating a sizing estimate for
SEISCO tankless water heaters. The calculations herein are based on industry flow rate standards and
normal environmental usage factors. The data generated by the calculator is for illustrative use only. All
sizing should be reviewed by a trained professional and all applicable code and licensing requirements
must be considered. In using this calculator, the user agrees to take full responsibility for the output