An electrical furnace just has blower at The underside and factors and may't run in tandem using a heatpump to supplement, as the heatpump's increase on coil is downstream with the furnace. Really need to shut down heatpump for factors to come on with an electric furnace and add-on coil, https://landenekosx.blogdal.com/36242514/not-known-facts-about-copyright-side-effects