The 3 stage furnace will provide better comfort. The middle stage is a nice bridge between the high and low stages. With the size of your house, a 60,000 BTU furnace will not be running in the high stage too often.

Is your 30 year old furnance a Carrier? If it is you can get an additional $100 rebate from Carrier.

SR

My current furance is a Lennox. So, we won't get the extra $100 rebate.

The contractor said that we need a condensation pump to take the moisture away. But he didn't say anything about a HEAT PUMP...

go two stg if you intend to pair with HP. three stage if you intend to pair with AC.

And BTW, don't cripple your furnace choice. The Infinity controller with the Infinity furnace is the only way to go.

IMO
Good Luck!

You know much more about heat pumps than I do. So please educate me.

I thought in a dual fuel system set up, either the furnance or heat pump is operational. The switch over is set by a predetermined lock out temperature. For example if the lock is set at 40 degrees, then heat pump would take care of heating needs above this temperature. For temperatures below 40, the furnance takes over.

Therefore in the dead of winter, when you several days of temperture below 40 degrees, why wouldn't you want the comfort of a 3 stage furnace? Am I missing something?