Hi, I have a few questions regarding furnace replacement.

First an overview. I live in Quebec, Canada. I have a "Lincoln" oil furnace, installed 20 years ago It works well, I have no complaints.

I also have a heat pump, manufactured by "Heil", installed in 2000, again, no problems or complaints.

During the winter, the heat pump supplies the heating at all times, except when the outside temperature goes below 9 degrees F. Then, the oil furnace is the source of heat. I use about 1/2-1 tank of oil per year.

Now the questions.

1- What is the average life of a furnace. Is it time to consider replacing at 20 years ?

2- I am considering upgrading to a high efficiency oil furnace. Will there be a considerable difference compared with a 20 year old furnace ?

3- If so, is there a problem with oil being in an indoor tank for a long period ( say I have to refill only every 2-3 years. Does furnace oil get stale ?

4- Will the serpentine in my oil furnace (for the heat pump) be compatible with the new furnace ?

5- I am also considering installing a heat recovery air exchanger. The model I am considering (Venmar) can be installed using existing ductwork (one set of inlet#outlet hoses go outside, another set of inlet outlet hoses go on the air intake of the furnace, 3 feet apart. Will this also be compatible with a high efficiency furnace ?

6- My chimney is an indoor brick chimney, with a 6.5 inch terra cotta interior. All seems to be in good condition. Will an insert be required with this type of furnace ?

7- There is a humidifier , a "generalAire" flow through humidifier attached to the furnace (hot air side) below the serpentine for the heat pump. Is this also going to be compatible ?

The reason I am considering the upgrade now, is I can get a 15% rebate from the government, if I replace it , but only for this year.

I will post the exact models of furnace and heat pump if required.

I thank you in advance for all the help, I want to be as informed as possible as I get estimates. I don't mind paying for what I need, but I don't want to pay extra for what I don't really need.