Not to beat a dead horse, but I did a quick calculation on how much generator I might want to get. 3500 watts doesn’t go very far.

If you go with an inverter, that’s about the best you can get for under a grand.


Is it worth it to go with a higher HP, standard generator and resign the fact that you will have to wait to watch tv?

Can a microwave work with a standard generator?

I found out last week that our gas furnace will not run on a portable generator.

We have a Predator 3500.

I would not run any sensitive electronics on one that isn't an Inverter unless I had a power conditioner / surge protector on them.

What can you run with an 8500 watt unit that you can't run with a 3500 watt? I got my Predator 3500 for $400 on facebook marketplace.

I run two TVs, wifi, water heater (gas), fridge, and septic. I assume I could have also got a space heater on it, but our heat wasn't out so I didn't try.

I admit you could get more on the 8500, but I don't think you're gonna be running a furnace or anything like that.

Bite the bullet and get a Generac.

Spend a little more and get a bigger generator. I’ve got a 9000 watt predator. We unplug all the electronics except for one TV and the internet router. I kill the breakers for the outside AC units, clothes dryer, and any major amp draws. I can run the entire house with no problem. Ran the pool pumps, septic pump, and furnace. I know it will not run the AC and I think the clothes dryer might be pushing it. Have not had a problem yet.

This is geared toward Patriot07's comments, but others as well. You have to define "furnace" to answer the question. If it's a gas-fired furnace, the power needed is for the controller board/thermostat (minimal) and the blower motor, which normally spins a squirrel cage fan that doesn't have a lot of start-up torque. I wonder what about your gas water heater uses electricity. The last 3 gas water heaters I've had used no electricity whatsoever. (The latest was a replacement 2 winters ago, so not very old technology.) Yes, if you get a wifi connected water heater, it will need electricity, but the vast majority I've ever seen need absolutely none. My septic system has a 1/3hp aerator that runs constantly. It also has a 1/2 hp pump that may require 1000w or more at start-up. That's ONE item on my load chart - and yours - that may consume almost 1/3 of your generator's watts when that load comes online. If you don't have enough surge watts (and inverters aren't known for being strong in that domain), then you'll "brown-out" and may trip the breaker - or damage something. Some refrigerator compressors will be failing over the next 6 months, but some people won't necessarily make the connection back to when they ran it on an overloaded generator.

Some of us have more than one refrigerator and/freezer. Anything with a motor is going to have surge current when it starts. That can be twice or more of the running amps. All of these things affect sizing a generator correctly. The small electronics loads you mention are not much - the device plate will often give watts consumed. Any motor or any resistive load (think electric heat) will eat up your generator's watts in a hurry. Example: a mere three common hand-held hair dryers (1200w) will use every watt of capacity of your generator. Not that you will run 3 of those, but it's just a point of how easily one can run out of headroom on generator size.

Likewise, one can have a generator that's just too big for the "sweet spot". All of them have a minimum fuel burn, and the larger the generator, the larger that amount. If I had a 10kw generator instead of my 7500w unit, I'd just need to plan to have more fuel on hand, or run out sooner - even with the same loads in each scenario. A generator that is loaded to the max will still work, but it too will likely burn more fuel under that unrelenting strain. This is no different that how a boater chooses to run his outboard; back off a bit and pay less at the pump, run it at max rpm and you're going to pay for it.

As for an electric furnace, it's not uncommon for them to have a 10,000w heat strip. That load alone will consume a 10kw generator - without even starting the blower motor. It's never very feasible to run ANY kind of electric heat with a generator; it's just too inefficient.

The name isn't what it once was. I have heard from repair shops I was in that they are junk. The branding was just sold to go on chinese low-ball junk.

Were you energizing both 120V legs of your panel? That can be an issue for some as different parts of the system may power from different legs of the supply. I went and looked at your generator model - it's 120v only. The issue probably isn't that your gas furnace won't run on a generator - it's more basic in that it won't run on ONLY 120v. Such are the pitfalls of a small simple generator. There's not one solution perfect for all needs.

I have maybe 45-50 days total on generator power and most on a 7000 watt. It's not enough for conveniences. Some necessities but you'll need to ration the item's time on them.

A lot depends on if you are all electric or have natural gas water heater, stove, and furnace. If you have all 3 I'd say 5500 to 6000 would suffice. I'm all electric so I need 10000 watts. I just trialed my salvage 13000 Generac portable during the ice storm. I had enough generator but not enough wire to feed my breaker box. I've ordered 25' of 4/4 fine stranded cable and changing to a 60amp breaker in my main box off this cable. I should be able to do whole house except central air and heat. I have 3 - 5000BTU window A/C units for the bedrooms if it's hot and 5 1500 watt space heaters and a fire place if it's in single digits. My heating plan kept my house at 70 with my fireplace.

As the old saying goes I'd rather have too much and not need it than have too little and not have enough. Kinda like you can never have too much horsepower. Go bigger than you think you want to. Watch FB market place this summer when people get tired of that portable generator taking up garage space.

I run tv's and computer without an issue.

I've never seen an inverter that does 220v either. You can't energize both legs of a 220v circuit with such a critter. You are absolutely correct that watts add up quickly - especially when looking at surge watt requirements for starting motors. We have no issue running an 1100w microwave; there's not really much surge to them. We also have no issue with running our electronics (modem, router, TV, laptops with AC adaptors, incandescent and LED lighting). We do not bother trying to use the countertop toaster oven - I never bothered to check the watts on it, but know it's much more than the glow-plug igniter for the natural gas oven we have. Therefore, we go with the gas oven when the power is off. With the glow-plug igniter, we need the generator on to use the oven, but can light stove burners with a hand lighter even if the generator is off.

Mudshark, what is that little kitten doing?

I'm sorry for the guys who don't know...I learned to never offer suggestions in electrical because Washington state is always on the latest NEC codes. Some states are still 05'. Or have nothing in stone😬 . Look we've all grown up and tought what daddy taught us + schooling later on for some....Good luck and I hope you found your way.

Why wouldn’t it?

His generator is 120v only. The gas furnace appliance likely uses both legs of 120v power from the distribution panel. The blower might even be 220v; I haven't seen the setup to tell you, but I'm fairly certain that the dead 120v leg is why.