The RGFD is one amazing furnace. My '09 replaced a 125,000 BTU furnace, but was still oversized for the home. My heat loss is 60,000, but I needed the larger blower for my 4 ton a/c.

Nevertheless, it still provided great comfort and yielded some gas savings, as the furnace will quickly ramp down to a level matching the heat loss. Ideally, the amount of oversize should be less than mine since at higher OD temps, there will be more periods of non-operation.

You want that sucker to run constantly at its lowest level for maximum comfort.

What is your present furnace (size, efficiency/age, etc)\

V

Current furance is a ~1990 York Stellar Plus. It is direct vented so I am told its a 90%. The repair guy has been telling me its a 60k BTU but the estimator (company owner) said it was 90k.

AC unit is a 2.5 Ton 9 SEER Energy Knight.

If (worst case) your furnace is a '60',then its output would be ~ 54,000 BTUH. The RGFD 09 at lowest output is ~ 34,000 BTUH.

Depending where you live (nearest big city) in WI, the OD winter design temps range from the low single digits, to about -20 degrees. In all likelihood, it would run constantly, which is ideal.

There is one caveat: The furnace is designed to handle air conditioners of 2 - 5 ton capacity.

V

I am about 20 minutes from Milwaukee. The proposed A/C units are 3 ton so it sounds like those are in the right range.

Thanks for all your input, it has been very helpful and is much appreciated!

The outdoor winter design temp for Milwaukee is -4 degrees.

By comparison, mine if 14 degrees. My house is a 2500 SF, 2 story in Phila. area with a heat loss of 60,000 BTUH. At -8 degrees, my furnace would run 100% of the time (66 degree indoor temp)and wouldn't cycle until the temperature got above 35 degrees.

If I were to move my house to your area, the furnace would run constantly at -4 degrees and would cycle at the same temperature. You could use these figures as a guide as compared to your house.

Make sure you get the model 412 stat as it has the new features of humidity control in winter, and on-demand dehumidification in summer. The wintertime function assumes you have a humidifier. Without those features, the 411 stat requires 7 wires to operate the furnace and 2 stage air conditioner. Single stage a/c will need 1 less wire. The installation should include running a new (preferably) 10 conductor thermostat wire (keep the old one in place). You'll have enough wires for any eventuality.

Since the contractor didn't do a manual J, he probably just 'looked' at your duct system. The new furnaces with VS blowers will work harder if the duct system is undersized or restricted, which could mean, premature failure. Ask him to check your static pressure and to estimate what your total static pressure (TESP) will be with the EAC. Most new furnaces are designed to run with a TEST of 0.5 inches of water column (rarely met). A little higher is O.K.

Good luck on your selection.

P.S., I am just a happy homeowner who did a lot of research, and interviewed a lot of contractors, before settling on one.

V