Home Backup Generator.

[Drew]

We are considering a home backup generator. Looking at Kohler and Generac. I wanted to check and see if the HiveMind had any constructive input? So far the plan is auto transfer switch, natural gas fuel. 20 kW. We have natural gas at the house, gas furnace.

My understanding is that the electrical side is pretty simple... split ground and neutral in what is now the main panel, route their blocks and the hots to new transfer switch which is now the main panel, and what was the main panel becomes a subpanel. Ground and neutral get bonded in the transfer switch (new main panel).

Wild Card is manual transfer switch, portable generator, and we take a risk of something happening while we're out of town... cuts the cost in half, but the Point of the Exercise is to not have to think about this anymore.

Any other brands? Kohler and Generac both have dealers here that have been good so far, both have provided quotes.

Any other input would be much appreciated. Grazi.

[Mabouya]

A buddy of mine at work recently went through the Kohler vs Generac decision and got a Kohler. I believe his choice was driven by the fact that Kohler had a model that met his requirement without having to go with a liquid cooling system. (going on memory here, I'm not 100% sure of that final point) He has the automatic transfer switch system, specifically so he doesn't have to worry about it if he's out of town.

One down side was that there was a very, very long wait for the hardware (well over 6 months) due to COVID supply chain issues. Check to see if those have been resolved.

Good Luck

[gregl]

We purchased a 16KW, air-cooled, Generac unit two years ago. The installation was as described in the OP, natural gas fuel and automatic transfer switch. I am pleased with the unit’s performance and would recommend Generac to potential buyers. The local dealer did a good job on the installation, with minimal issues noted by picky me. Here’s the positives from my perspective:

- It works reliably, exactly as advertised. We sized the generator for the whole house, including AC. It’s super convenient to have every feature and appliance in the house usable when the power fails.

- IMO it’s well designed and constructed. I do my own routine maintenance and I’m always impressed with the unit when I have it opened up.

- The unit runs and self-tests weekly, bi-weekly, or monthly as desired. We configured this to occur mid-month, mid-morning to avoid annoying the neighbors.

- Routine maintenance is very simple. The unit is designed for easy access to all maintenance items. After maintenance, you need to reset the maintenance minder. If not reset and maintenance intervals are exceeded, the unit won’t start. Pro tip: make sure the installer gives you their maintenance reset code. I told the dealer that I wanted the option to perform my own maintenance or no sale. Accordingly, the code is written inside my owner’s manual.

- The unit is well suited to cold weather. The battery and oil systems have heaters to ensure the unit starts well in cold temps.

Only two issues I don’t care for: (1) It’s a bit noisy. Not too bad when you’re inside with doors and windows closed, but it’s a good idea to install the unit as far as possible from bedrooms. (2) You have to pay an annual subscription to use Generac’s web-based monitoring and control app. After paying $$$ for the system, monitoring should be free!

Hope this helps!

Greg

[monadnocky]

Whole-house Kohler here (where we lose power A LOT), 16KW. We have a local generator guy do the yearly maintenance; all I do is just add oil when it's needed (it's rarely needed).
Monitoring app is free and pretty handy. Can even start the thing if you're in Timbuktu, if you wish.
Self-test we have scheduled for 20 minutes every Sunday at noon.
It's noisy, relatively so, like Gregl said, but not obnoxiously so. Still, place it away from bedrooms if possible.
We feed it from a buried propane tank - not sure of the size of the tank, but even with two of those snowman-sized bottles I wouldn't be confident of it lasting for more than a couple of days here.

[monadnocky]

- The unit is well suited to cold weather. The battery and oil systems have heaters to ensure the unit starts well in cold temps
Greg

Greg- I'm curious about this - how does this work? I'm not aware if my (Kohler) has any such system and I think it would drain the battery pretty quickly? Never had a problem starting up, even in very cold weather here in NH, so now I'm wondering if there is something and I'm not even aware of it? I'm not aware of any (domestic) power being supplied to the unit.

[gregl]

Greg- I'm curious about this - how does this work? I'm not aware if my (Kohler) has any such system and I think it would drain the battery pretty quickly? Never had a problem starting up, even in very cold weather here in NH, so now I'm wondering if there is something and I'm not even aware of it? I'm not aware of any (domestic) power being supplied to the unit.

Domestic power is supplied to the Generac system under normal circumstances. This enables battery charging, heating, and system diagnostics to be continuously powered. Both the battery and oil filter have electrically heated blankets around them.

Greg

[monadnocky]

Domestic power is supplied to the Generac system under normal circumstances. This enables battery charging, heating, and system diagnostics to be continuously powered. Both the battery and oil filter have electrically heated blankets around them.

Greg

Huh, looking online I see that Kohler has these kits as well. Now I'm thinking that, when it was installed, they might have hard-wired these accessories, as my unit routinely starts up in less than 0 degrees F. I'll open it up later today and check it out now that I know what these look like.
Things I never knew....

[j44ke]

Keep the mud dauber wasps out of your generator’s gas regulator vent and the other air tube off the engine. I fabricated wire mesh caps for each after the buggers got in and partially filled the regulator with mud. Screening was just enough to keep the wasps out without restricting air flow too much. Wasps seem to love generators.

Also check the oil regularly.

I think the tendency is more often to get too small a generator than too big. My guess is that power outages are more likely to get longer than shorter in the future. Make sure you have the power and fuel supply for longer run times.

Also a good idea to have whole house surge protectors to protect all the chip boards in your appliances from electrical variances during a power outage and generator run. And run UPS/surge protectors on sensitive/expensive appliances to be extra cautious. The amount of computers in things you’d never guess had them is kind of ridiculous. A lot of gas stoves are not off-grid appliances, because everything in them operates by wire, not knobs and valves.

A neighbor has wired in an outlet for an all-in-one battery so the weekly generator tests keep the battery charged. The battery will give him enough juice to run things in the house if the propane tank runs empty and the tanker truck can’t get there immediately. The box is pretty big and heavy, but once wiring is done, it just plugs in. He can just as easily connect to a photovoltaic panel.

[Too Tall]

Jake's neighbor is cool. He gave me detailed plans for that battery. Need to hit Whole Foods first.

Potato-Battery-and-voltmeter-scaled.jpg

[Mark Kelly]

I think the tendency is more often to get too small a generator than too big. My guess is that power outages are more likely to get longer than shorter in the future. Make sure you have the power and fuel supply for longer run times.

On the other hand generators lose efficiency when run at fractional power: this is logical because the motor still consumes fuel with the generator idling. In rough round terms if a generator uses 100 units of fuel at 100 percent capacity it will use 15 - 20 units at idle; interpolation between those points will give you a good estimate of fuel use at fractional power.

[j44ke]

Jake's neighbor is cool. He gave me detailed plans for that battery. Need to hit Whole Foods first.

Potato-Battery-and-voltmeter-scaled.jpg

Hah. He’s probably more of a prepper than a Whole Foodist. Brand of his battery is Bluetti, though calling it a battery is an understatement. It seems to do a lot of things. A few more than those potatoes, except you can’t eat it.

https://www.bluettipower.com/

Our generator is a Winco. It is powered by a Honda engine. It is connected to the house by an Asco Auto-Transfer Switch.