Modine Effinity PTC Greenhouse Heater greenhouse insulation 20 foot greenhouses with 60 foot length 20 foot greenhouses with 60 foot length provide a 1200 sqft greenhouse space DSC 1 CO2 control device module allows user to easily connect and control standard supplemental CO2 devices or CO2 exhaust controls to the Hydro x Modine Effinity Greenhouse Heaters with Building Management System Integration (PTC BTC) are high efficiency commercial gas fired heating units with up to 97% thermal efficiency (compared to 80% for the PTP models) These greenhouse heaters dramatically lower energy costs and CO2 emissions by coupling of our secondary heat exchanger technology with our robust tubular primary heat exchanger design