I have an Aranet 4, mostly able to keep things around 600 with a little bit of ventilation. It goes up when we're together in a small room with no door open, I

I have an Aranet 4, mostly able to keep things around 600 with a little bit of ventilation. It goes up when we're together in a small room with no door open, I'm planning on eventually retrofitting MVHR which should help improve indoor air quality and allow me to insulate. In the meantime the Aranet is good for getting a handle on general air quality and how you can improve it.