Necessity and cost savings are the mother of invention, or something like that. New construction, in an attempt to prevent drafts, uses materials and techniques that have created a virtually impermeable structure. Homes nowadays are so closed off, in fact, that the outdoor air movement that equalized the air pressure within and without has been cut off. That includes the naturally occurring humidity and fresh air. To that end, heating and cooling specialists have created a ventilation unit that is included in many new builds and can be added to older homes after the addition of energy efficiency upgrades like new windows and insulation. These are called HRV and ERV units. What are HRV and ERV units and do you need one?
Also known as a Heat Recovery Ventilator, an HRV is an add-on unit for your current forced air system that will take the heat in the stale indoor air and preheat the fresh outdoor air, circulate that fresh preheated air through your home to create a comfortable indoor environment. This is ideal for cold weather. An HRV will also remove humidity and heat from the outdoor air during summertime, pre-cooling it. Either way, this reduces the amount of energy needed to bring outside air to the comfortable indoor air temperature and saves energy costs for the homeowner.
An ERV stands for Energy Recovery Ventilation. It does everything that an HRV will, but it also captures moisture. An ERV will take the humidity in the indoor air being extracted and transfer it to the incoming air in the cold months. In hot and humid months an ERV will extract the humidity from incoming air and to help keep the indoor air at a reasonable humidity, this helps keep your home cool when it is hot. This is helpful in keeping the home at an ideal humidity, between 30% and 50%.
Incoming and outgoing air never mix. The heat recovery process means that incoming and outgoing air pass through separate channels using a heat exchanger to transfer temperature and humidity as needed.
Most on-the-market HRV and ERV units are 55% to 70% energy efficient. How does that compare to a Napoleon HRV or ERV? Ours reach 80% efficiency and are three times more efficient than the current energy star requirements.
The unit you need, an HRV or an ERV, depends on the climate you live in. The winter months north of 35° longitude can get pretty cold. Cold air means dry air and, in this climate, the ERV is an ideal choice. Hot and humid climates like Texas, Georgia, and Florida are well suited for the ERV as well. In moderate and coastal climates, either unit will be perfectly fine. And finally, in hot and dry places like New Mexico and Arizona, an HRV is recommended.
An HRV and ERV are a valuable addition to your home’s indoor air comfort, especially brand-new homes, or those that have just undergone energy efficiency upgrades. Both feature a heat exchanger that will either add heat to cold air in the winter or subtract heat from hot air in the summer. To ensure that you have the best unit for your home, consult your local heating and cooling professionals for help.