I think IKEA is on the right track with their lower efficiency filter. For a standalone air filter, you care about the rate of removal of contaminants, which i

I think IKEA is on the right track with their lower efficiency filter. For a standalone air filter, you care about the rate of removal of contaminants, which is roughly (concentration of contaminants) · (flow rate) · (filter efficiency), and you probably end up caring the most about the particle size at which the filter is least efficient. So a real HEPA filter has .9995 for that last factor, and .99 is barely worse. Even MERV 13 at 75% or so isn’t so bad. For a given amount of power consumption, you end up with (concentration of contaminants) · (flow rate) · (filter efficiency) / (power), which is (at fixed contaminant level and a fixed quality of fan) roughly proportional to (filter efficiency) / (pressure drop at design flow rate) and this is where IKEA is making the right tradeoff: those non-HEPA filters have considerably less pressure drop and only fail to filter a percent or so of the air going through.