This is a big change coming in residential & light-commercial furnaces. Effective June 1, 2013, federal law requires that minimum furnace efficiency in the Northwest must be 90%. That means that 80 percent of furnaces cannot be installed after that date.

All things being equal, many people would opt to pay the upcharge for a 90 percent furnace anyway. But there are some jobs where it is not feasible to retrofit a 90% furnace. For example, if you have a situation where a chimney is venting for an 80 percent furnace and a gas water heater, and there is no path to run a new PVC vent for the 90 percent furnace, that is going to be a problem.

You can’t vent the 90 percent furnace in the chimney with the water heater, and if you dedicate the chimney as a path for the 90 percent furnace vent, the chimney can no longer be used to vent the water heater. This is a dilemma that could be very difficult and/or expensive to solve. Unfortunately, there are no exceptions in the code for such difficulty. All I can say is that it will take some creative minds to solve this problem.

At Air Control Heating and Electric, Inc, we feel we can do anything, but this will add to the cost.