Restricted airflow return in HVAC

Hi all

I'm replacing an electrostatic air cleaner in the return line of a forced hot air/AC system. With the cleaner out the air flow is vastly improved at the outlet registers, presumably because there was previously some restriction to return. And yes, the return registers are open.

Is there value to adding a register just prior to the air flow cleaner,

thus sucking air from the basement as well via the return ducts.

Any thing else I can do.

There is no opportunity to add returns or change the duct size unfortunately.

Thank you very much

Hmmm. Thats good advice.

However, in winter the basement is fairly warm (roughly equal to the house temp) and summer it is fairly cold (much colder than the rest of the house). Would that mean its OK to circulate basement air to the first and second floors??

Many thanks.

Almost all filters reduce airflow somewhat (even more when dirty). High efficiency filters which get small particles out tend to add more resistance than a cheaper filter. Try a different filter brand or type (same size)

No value adding another air return since the restriction is the filter not the passageway to it. Mixing cold air from the basement will only encourage warm air from the first floor to flow into the basement to replace it thus increasing the heating load of the house and costing you money. (unless you want a warmer basement)

It is possible that the lower flow rate is the correct one and operating without the air cleaner causes too high airflow which will translate to more rapid cycling of the furnace. More isn't always better