I live in New Jersey, and in preparation for future severe-weather-related outages, I would like to have a backup plan in order to power my natural gas furnace, as well as the fridge/freezer and a few lamps. I have a Carrier Performance furnace, installed within the last couple of years.
My main concern is getting a generator that is compatible with the sensitive electronics in the furnace. My initial research has turned a number of articles that indicate the significance of a clean, stable power supply, however I have not found anything more specific than that.
I am currently looking at two paths:
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Get a traditional 5000W-7000W generator. A number of these seem to indicate some type of Voltage Regulator, however am I right in thinking that the output they give is still somewhat dirty, with a higher chance of frying the control board in my furnace? The size of this generator should be more than enough to power everything I described previously, along with a few more circuits. I would also think about a conversion kit to give me the option to use propane as well as gasoline.
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Get a ~2000W inverter generator, which, as far as I understand, would give much cleaner power, and better gas consumption, but with a more limited output that will reduce the number of devices I can power.
I am not looking at going the whole house generator route, which is beyond my budget. I am in the process of tracking down a good electrician to walk through the plan and discuss install the appropriate transfers switches etc. that may be required.
Am I heading down the right track here, or is there something else I should consider?
Best Answer
I would not recommend a square-wave/modified-square-wave generator to run your furnace. The control boards in them are particularly sensitive to high-frequency noise induced in those sort of designs. One particular failure mode is that non-sine inputs cause excessive heating in inductive components, whether they be AC motors or current-filtering inductors on the control board.
Looking around, it seems that gas furnaces should be provisioned for 350W, and about the same for a typical refrigerator. 700 watts of steady-state load isn't bad, and I would argue that a 2000W steady-state pure-sine generator could handle the transient loads from start-up currents no problem, leaving plenty of room for laptops (75W - 100W), cell phone chargers (~10W), and lights.
Go with the pure-sine wave.