[Hitagain]

Depending on how well your house is sealed up, you may need to add make up air if you add a oversized exhaust fan. Use a ERV/ HRV just drawing air from the smoking room and returning air to the Return air of the HVAC system. This would exhaust the smoke filled air to the outside and replace the air with fresh air coming in and most ERV /HRVs will recover about 70% of your Heating/ cooling costs. I would think you would need to filter the exhaust air entering the ERV/ HRV to protect the heat exchanger. Just an idea....