</font><font color="blue" class="small">( He has been in the business for about 25 yrs and is of the opinion that the new high efficiency furnaces cost just as much to own/operate as the 80% hot vented ones. He says you will either pay for higher costs on purchase and service on the high efficiency ones or gas for the 80% ones, which seem to never break.
Ben)</font>
Ben, you might have been mislead a bit in your friends statement. Today's 80% furnace has just about as many controls on it as the 90% plus furnaces. So from a operation stand point there isn't much difference. Yes you only save 10% on fuel. If you go back to prior 70% where there was just a gas valve, pilit light, limit control, blower and heat exchanger yes them furnaces never broke down. Today nothing can be manufactured less than 78% and all furnace's pretty much all have the same controls on them now. The 90's do have a couple more safety switches over the 80's but that is about it. Now most manufactures have even gone into Variable drive blower motors, again you can get them in 80 and 90%. In Minnesota we don't even sell the 80%'s anymore. In new construction our codes pretty much have forced everyone to go 90% or better. Sealed combustion is another requsite for Minnesota which is not made in the 80% range. My opinion being the business since 1976 is to go with a variable drive 94% or better. The variable drive being DC voltage will use about 80% less electricity over some standard blower motors.
murph