Frank,
First of all, WAY TO GO on getting that oil hog out of your house. The whole world is now a better place and you will have some more money in your pocket. I lived in an old house a couple years ago with an oil furnace and before I put in my wood stove that hog cost me about $700 per month!
You ABSOLUTELY don't want to use those unvented heaters for too long as your main heat. They will smell up your whole house and your clothes. You won't notice but watch how people look at you when you go out in public. They can smell it on you. That aint good and you are breathing those fumes. Keep them tuned up and really watch your fuel to make sure it does not have any water in it. If those things malfunction in the night, your home could be ruined and your health could be at risk.
If you want to use oil heat but do so more efficiently, I suggest going to an oil stove or a more complex heater like a monitor or lazer. I handle all of them so let me know when you are ready to do something and I can surely help. An oil stove will work without power and can use either kerosene or #2 fuel oil. A monitor or lazer will require electricity and will use K1 Kerosene. This will alow you to use your tank and line setup while zone heating. My biggest oil stove will heat about 2,000 square feet and only consumes .3 (1/3) gallons of fuel per hour when running!
If you want to go to something completely different wood or pellets are a good choice. I can help with either. In that case, you can get a few bucks for your tank and the buyer will come and get it so you don't have to worry there. If you gave it away for the removal, I bet it would be gone the day your ad came out. List it in the IWANNA or CRAIGS LIST locally.
Give a post back if you need more help or email me. If we post here others can benefit.
Warm Regards,