As far as I know they only put them in the super expensive houses that are made extremely tight. If they use spray foam insulation then there is very little air circulation so that they need to add an ERV just to get enough air to breath.
Check your code requirements. I am in the USA and they are required, but I am in the north where we have very cold winters and humid summers. You should consider putting one in if you don't have one.
What country are you in? I'm in the US and my nice home, built in 2015, doesn't have either one.