When you decide it’s time to install a home ventilation system, there are a number of factors to consider when choosing between an HRV or ERV, including things like your climate, how many people live in the house, and more.
Factor 1: Climate
Climate is one of the most important considerations when choosing between HRV and ERV. HRVs function best for mild and humid winters, but they can function well in cold climates as well, as long as you have adequate ventilation in your home to remove excess moisture from bathrooms and the kitchen.
ERVs function best for colder, drier winters and hot summers, because they can keep moisture inside if the air outside is dry, or prevent exterior moisture from getting in.
Factor 2: Household size
The size of your house and number of people in your family will also make a difference to the system you choose. Humans create a great deal of moisture from breathing, sweating, cooking, and bathing, so the more people there are in your house, the higher the humidity will be.
HRVs are best suited for larger families that tend to cook and clean often. They’re also good for smaller and medium homes where moisture can build up in the air.
ERVs, on the other hand, are better suited for smaller families that don’t generate a lot of excess moisture, and they also work well for large homes that dry out quickly.
Factor 3: Age of your home
Ever since the late 1970s, building codes and practices have resulted in new homes being more airtight than older ones. ERVs are great for older and drafty homes where humidity can escape and leave the air dry. HRVs are better for newer homes that don’t suffer from too many drafts and air leaks.
Factor 4: Existing heating system
ERVs are ideal if you have a furnace that tends to dry out the air in your home. The ERV will retain higher humidity levels and make the air more comfortable. HRVs are great if you have a boiler system that doesn’t dry out the air.
To recap: HRVs work best for large families living in small, airtight homes in cool climates, while ERVs are best for small families living in larger homes in cold climates.
Single-room versus whole-home systems
HRV and ERV systems are available in single-room and whole-home models. Whole-home units are great for overall air quality, but your home has to have extensive ductwork in order for them to work. For one thing, there needs to be ductwork and vents to circulate air around the house, but there also needs to be an exterior vent for air intake and removal.
A single-room unit can be mounted in a window or installed in a wall opening, eliminating the need for extensive ductwork in the house. Most homes in Canada have ductwork, so whole-home options are often ideal, as the HRV or ERV can be installed near the furnace.
HRV and ERV systems aren’t typically practical in mild climates, especially if you don’t have a furnace to heat your home in winter or an air conditioner to cool it in summer. Because the difference in temperature between interior and exterior air is often minimal, you might be better off opening windows, using fans, or using another ventilation method instead of spending the money required to install, maintain, and operate an HRV or ERV. These systems are far more practical for homes that experience high humidity in winter or summer.
Given that most of Canada’s population lives in a temperate climate, with cold winters and hot and humid summers, these systems are worth considering for most homeowners.
Energy savings and efficiency
HRV and ERV systems are often used in cold climates to help keep homes warm and ventilated in winter, and they are highly effective in these situations. However, they can also offer energy savings in hot climates because they can reduce the burden on your air conditioner and lower your cooling bills.
There are also energy-efficient HRV and ERV systems on the market that will further lower your energy bills. ENERGY STAR certification is only granted to HRV and ERV systems that have a sensible-heat recovery efficiency (SRE) of 65 percent at 0 C and 60 percent at -25 C. It should be noted that systems that are equipped with electric resistance heaters aren’t eligible for this certification.
Higher-end HRVs and ERVs often come with a warranty. This often includes something like a 10-year or lifetime limited warranty on the heat recovery core plus a two- or five-year warranty on other parts. In order to receive ENERGY STAR certification, HRV and ERV systems must come with a one-year warranty at least.