Flue cap with filter

A flue pipe filter device for reducing nitrogen oxide (NOx) emission levels from gas fired appliances, the device comprising:

• a flue cap with a pipe connection adapter sized to attach to an existing exhaust pipe;
• a fanned flue cap body with vents operatively attached to a distal end of the pipe connection adapter;
• a filter positioned within the fanned flue cap body, the filter designed to convert NOx emissions into reduced NOx emissions;
• and
• a lower flue having a first end and a second end, wherein:
• the first end is operatively attached to the pipe connector adapter;
• the second end is attached to the fanned flue cap body;
• the fanned flue cap body comprises a lower cap with a central tubular member sized to attach to the lower flue;
• and
• the filter is positioned within the central tubular member, such that exhaust flowing through the lower flue into the fanned flue cap body passes through the filter.