You pull up the website where all of the information the IRS knows is already prefilled. You click on the "Efficiency Improvements Exception" box and add the v

You pull up the website where all of the information the IRS knows is already prefilled. You click on the "Efficiency Improvements Exception" box and add the value of your furnace. Click on any other things the IRS missed and add them. Click "submit" to finish the tax return. Done.