What is an HRV?

HRV stands for heat recovery ventilator.  This unit is a system that is designed to exchange the stale stagnant air from within a building for fresh air from the outside without losing too much of the heat you are paying to generate.  Creating good ventilation is vitally important in managing the levels of relative humidity, carbon dioxide, and VOC’s (volatile organic compounds) that may build up in occupied buildings.

When is an HRV installation recommended?

If you are designing a new or remodeled energy efficient home, an HRV is a great way to meet Washington State’s ventilation code requirements without suffering from higher energy bills.  If you home has been having problems with odors, humidity, condensation, or VOC’s a heat recovery ventilator installation may be a good long-term solution.

What does an installation look like?

Most  HRV installations in existing homes are done when no ducting currently exists.  We can install the unit which is aesthetically appealing and quiet in a closet or mechanical room and install adjustable vents in several rooms of the home.  This limits the need for additional sheet-rock repair work and prevents taking up too much storage space.  You can also have a unit installed to in conjunction with your existing furnace and utilizing the duct-work that is already in place.

How can you determine what size HRV is needed?

Determining how much ventilation is needed is actually quite simple.  In general, we utilize the table provided by ASHRAE (found in 62.2).  Below you can see an example of how this table can be applied, the flow rates cited are in CFM (cubic feet per minute):

Recommended Ventilation Rates:

As per 2013 ASHRAE 62.2 (these requirements are in excess of Washington State’s most current building codes, but Hawk Environmental Services prefers a more liberal ventilation plan)

Floor Area

in Ft2

Number of Bedrooms

1

2

3

4

5

<500

30

38

45

53

60

501-1000

45

53

60

68

75

1001-1500

60

68

75

83

90

1501-2000

75

83

90

98

105

2001 – 2500

90

98

105

113

120

2501-3000

105

113

120

128

13

3001-3500

120

128

135

143

150

3501-4000

135

143

150

1558

165

4001-4500

150

158

165

173

180

4501-5000

165

173

180

188

195