I'm trying to decide between a single or two-stage high efficiency furnace. We live in Toronto in a 2400 square foot two-story house. The basement is unfinished. Heating throughout the house is uneven and some of the rooms are quite cold in the winter. The air conditioning doesn't work well either, apparently because the fan on the current furnace is not strong enough to push the air. Our current furnace is 19 years old and something like 70% efficient. I've met with four companies and three of the four recommended a two-stage furnace. They said that it would even out the heat in the rooms and was significantly quieter. The other contractor claimed that the opposite was true and that it would actually magnify the temperature problem. He claimed that though the new furnace would do a better job pushing the air, that with a two-stage furnace since it would run mostly at the lower stage, pushing cooler air, that the rooms that were problematic would feel cooler, not warmer. He also said that though a two-stage furnace is a little quieter, most of the time it's running on a lower stage so you're not really comparing apples to apples. If both were running on the higher stage, the difference wouldn't be great and overall, in the house, it is not very significant. He said that to even out the heat, we would need to run the fan continuously to circulate the heat in the house, but that the two stage wasn't the answer since it would feel like it was blowing cooler air. We're moving in the next year or so and though the cost differential between the high efficiency single and two-stage models isn't great, I certainly don't want to buy something extra that we don't need. Can anyone help me make sense of this. The contractor that told me not to buy the two stage model seems very knowledgeable and was an installer, the others were salespeople though from reputable places.