To be Variable or not to Variable
terry26.I live in your area.I don't know how much you understand about this stuff.You said what you were going to buy a given furnace than asked what it was.
I can tell you for a fact that you want the two stage furnace.That is in referance to the gas valve.The variable speed part that people talk about is in referance to the blower motor.That the blower(fan) that moves all the air around your house.If you are going to also have a electronic air filter installed so that you can filter the air in your home 24/7/365 than you want the variable blower.This is because of the energy savings provided by this type of motor.If you are installing air conditioning
than you want the variable motor.This is because of the ability of the motor to"wind"down during the cooling cycle.This helps alot with the removl of humidity.There are more reasons to be variable or not to be variable but if you answer to these first two questions is no then you have no need for the variable speed blower motor.As far as your question about which efficiency you want 80% or 90%.You need to look at your present natural gas consumption.Also what kind of efficiency your present furnace is.With that information you can ballpark your saving with the 90% furnace fairly easily.There are alot more accurate ways to calculate the savings but that the easest way.Other considerations for a 90% over a 80%.Noise the 90% furnaces have a enclosed combustion chamber.They are a LOT quiter than a 80%.So if the location of the furnace is in the
house.do you have to turn up the tv when the furnace comes on?How long are you going to be in your present home?Meaning are you going to be there long enough to recover the investment of the 90%? Something else to consider that most of the heating and a/c companys don't seems to bring up.Have you considered a heatpump?If you spend the time to calculate you energy use to heat you home(btu's) than you can look at how much you pay for which kind.Electic,LP,Natural Gas,Wood.One thing in this regard, that I considered.Was what fuel prices I thought were going to remain the most stable.The anwser in the Seattle area is electricity.One of the benefits of a heat pump is the air conditioning.