
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 (ft2)
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 (m2)
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
--- 3 2 --- 2 5 4778 4778 7690 6636 10603 9990 4071 4071 8143
--- 2 9 --- 2 0 4531 4531 7090 6294 10057 9310 3861 3861 7723
--- 2 6 --- 1 5 4285 4285 6520 5952 9510 8650 3983 3983 7967
--- 2 3 --- 1 0 4039 4039 5970 5610 8964 8000 3759 3759 7509
--- 2 1 --- 5 3800 3800 5440 5268 8417 7380 3525 3525 7051
--- 1 8 03410 3410 4840 4925 7871 6640 3297 3297 6594
--- 1 5 53095 3095 4360 4583 7324 6060 3323 3323 6647
--- 1 2 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
235 1425 1425 1880 2531 4045 2870 2017 2017 4034
440 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.