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Dwell
Two simple steps to help you choose
the ideal unit for your living space
Step 1
U.S. Department of Energy
Climate Zones Map
In what climate zone
do I live?
Browse the climate
conditions where
you live to determine
whether you need
a Heat Recovery
Ventilator or an
Energy Recovery
Ventilator.
HRV Required
HRV Recommended
Step 2
HRV Recommended
HRV or ERV
How much ventilation
do I need?
ERV Required
HRVs are usually recommended for colder climates with longer heating seasons.
ERVs are used for warmer more humid climates with long cooling seasons.
Living area
Number of bedrooms
0-1
2-3
4-5
sq.ft.
6-7
>7
cfm
< 1,500
30
45
60
75
90
1,500 - 3,000
45
60
75
90
60
75
90
105
120
4,501 - 6,000
75
90
105
120
135
6,001 - 7,500
90
105
120
135
150
> 7,500
105
120
135
150
165
The standard defines whole house and local ventilation needs. Whole house
ventilator sizing is based on the home’s overall liveable surface area and the
number of bedrooms. The whole house ventilation is the continuous ventilation
rate required to meet the minimum requirements of the standard, represented in
the table to the left.
105
3,001 - 4,500
The American Society of Heating, Refrigeration and Air Conditioning Engineers
(ASHRAE) has developed a guideline to evaluate the minimum ventilation needs
of a home according to ASHRAE Standard 62.2, Ventilation for Acceptable
Indoor Air Quality.
Table 1. Ventilation needs of a home, ASHRAE 62.2
fantech
Along the left side of the table simply select the size of the home; then find the
corresponding line matching the number of bedrooms; the resulting number is
the amount of CFM you will need in a whole house ventilator. An HRV/ERV can
also be used to meet local ventilation needs if a dedicated duct system exist
otherwise bathroom and kitchen exhaust may be required to meet minimum
ventilation needs.