
9
METHOD TO SIZE ERVs and HRVs
Ventilator Sizing
Tables 1 and 2 should be used to determine the required airflow for a home. These guidelines are taken from ASHRAE 62.2--2007.
Table 1 – Ventilation Air Requirements, cfm
FLOOR
AREA (ft
2
)
BEDROOMS
0---1
2---3
4---5
6---7
>7
<1500
30
45
60
75
90
1501---3000
45
60
75
90
105
3001---4500
60
75
90
105
120
4501---6000
75
90
105
120
135
6001---7500
90
105
120
135
150
>7500
105
120
135
150
165
Table 2 – Ventilation Air Requirements, L/s
FLOOR
AREA (m
2
)
BEDROOMS
0---1
2---3
4---5
6---7
>7
<139
14
21
28
35
42
139.1---279
21
28
35
42
50
279.1---418
28
35
42
50
57
418.1---557
35
42
50
57
64
557.1---697
42
50
57
64
71
>697
50
57
64
71
78
HEATING AND COOLING LOAD CHARTS
Although the ventilators process the outside air before it enters the home, additional heating and cooling loads need to be considered.
HEATING LOAD BTUH (APPROXIMATE)
OUTSIDE
TEMPERATURE
HEATING LOAD (BTUH) @ INSIDE DESIGN TEMPERATURE 72
°
F (21
°
C)
HRV
ERV
Deg. C
Deg. F
SVB1100
SHB1100
SVU1157
LHB1150
LHB1250
LVU1330
SVB1100
SHB1100
LHB1200
---32
---25
4778
4778
7690
6636
10603
9990
4071
4071
8143
---29
---20
4531
4531
7090
6294
10057
9310
3861
3861
7723
---26
---15
4285
4285
6520
5952
9510
8650
3983
3983
7967
---23
---10
4039
4039
5970
5610
8964
8000
3759
3759
7509
---21
---5
3800
3800
5440
5268
8417
7380
3525
3525
7051
---18
0
3410
3410
4840
4925
7871
6640
3297
3297
6594
---15
5
3095
3095
4360
4583
7324
6060
3323
3323
6647
---12
10
2795
2795
3900
4241
6777
5500
3215
3215
6430
---9
15
2465
2465
3400
3899
6231
4870
3107
3107
6214
---7
20
2195
2195
3000
3557
5684
4350
2834
2834
5669
---4
25
1935
1935
2610
3215
5138
3850
2562
2562
5124
---1
30
1680
1680
2250
2873
4591
3370
2289
2289
4579
2
35
1425
1425
1880
2531
4045
2870
2017
2017
4034
4
40
1200
1200
1560
2189
3498
2430
1744
1744
3489
COOLING LOAD BTUH (APPROXIMATE)
Outside
Enthalpy
Cooling Load (btuh) @ Inside Design Temperature
72
°
F (21
°
C) and 50% Relative Humidity
HRV
ERV
Btu/lb
SVB1100
SHB1100
SVU1157
LHB1150
LHB1250
LVU1330
SVB1100
SHB1100
LHB1200
30
482
482
990
670
1071
1390
320
320
640
31
785
785
1650
1090
1741
2310
520
520
1040
32
1086
1086
2310
1509
2411
3240
720
720
1441
33
1388
1388
2970
1928
3080
4170
920
920
1841
34
1690
1690
3630
2347
3750
5090
1120
1120
2241
35
1992
1992
4290
2766
4419
6020
1320
1320
2641
36
2293
2293
4950
3185
5089
6940
1520
1520
3041
37
2595
2595
5610
3604
5759
7870
1720
1720
3441
38
2897
2897
6270
4023
6428
8790
1921
1921
3842
39
3198
3198
6930
4442
7098
9720
2121
2121
4242
40
3478
3478
7590
4831
7767
10650
2321
2321
4642
41
3802
3802
8250
5280
8437
11570
2521
2521
5042
42
4103
4103
8910
5699
9107
12500
2721
2721
5442
HEATING LOAD BTUH
The heating load chart shows the heating loads in Btuh for a range
of winter design temperatures for each model of ventilator.
COOLING LOAD BTUH
The cooling load chart shows loads in Btuh as well. To use the
cooling load chart, first find the design enthalpy from a
psychrometric chart using the design dry bulb and wet bulb
temperatures. The cooling load can then be found for a range of
enthalpies for each ventilator.