During winters in the Twin Cities, homes face a major problem with indoor air quality: they can’t enjoy fresh air because that would mean opening up doors and windows onto outside temperatures that are sometimes –10°F and rarely higher than freezing. Sure, you could turn the heating system up as high as it will go to try to counter the cold weather, but not only will that not work well (it’s hard to stop a blast of freezing cold wind!) , it’s a tremendous waste of energy.
This is where heat and energy recovery ventilators are so useful. HRV and ERV systems allow fresh air to enter a home, but pre-heat the fresh air before it reaches the living spaces. Instead of generating heat to apply to the air, HRVs and ERVs use the heat already in the house to raise the temperature of the incoming air. This is the “recovery” part: these devices recover the energy already used to heat the inside of a home and use it to warm the incoming fresh air. Thanks to an HRV or ERV, a Minnesota home can have fresh air moving through the rooms, replacing the stale air, without putting stress on the heater or creating cold drafts.
Summer ERV and HRV operation
But you’ll only get use out of an HRV or ERV during winter, right? No, not at all! The good news is that both heat and energy recovery ventilators are useful in summer as well.
The wonderful thing about the design of heat and energy recovery ventilators is that they can work in two directions: warming up cold outside air, or cooling down hot indoor air. You don’t have to make any adjustment to an ERV or HRV to switch between winter and summer operation: they do the change on their own.
For example, let’s take a look at a standard energy recovery ventilator in action. The ERV is integrated into the ventilation system, where it draws fresh outdoor air through an exterior vent. The air from outdoors is passed through a heat exchanger, where it is run through a current of indoor air. A process called cross-current heat exchange takes place, where the hotter of the two currents loses its heat to the other. During winter, the hotter current is the stale air from indoors. It heats up the fresh outdoor air. The process simply flips during the summer: the hot outdoor air loses its heat to the cooler indoor air, lowering the temperature of the outdoor air.
Depending on the type of system you have installed, the may also help with humid summer conditions: moisture from the incoming outdoor air passes to the outgoing indoor air, helping to balance out humidity levels in the house.
Contact us for more information or to schedule service.
If you are interested in installing a heat or energy recovery ventilator in Minneapolis, MN, contact one of our staff members today. We’ll help you choose between the two (a short explanation about what makes the two different) and then have the new unit integrated into your ventilation system. You’ll start enjoying fresh air this summer and be ready for winter as well. We are also happy to help with any of your indoor air quality needs.
Freedom Heating & Air Conditioning, Inc. serves Minneapolis-St. Paul and the surrounding areas.