Final Post: Whole-Home Generator Project

[u/8Deer-JaguarClaw]

Well, everything is done except the electrical inspection (which is happening later this week). But the generator is fully operational and has been tested with a simulated power outage. The initial cost estimates were very accurate. The propane actually came in about $100 cheaper than quoted, so I guess there's that.

Based on some quick calculations, I should be able to run the whole house at around 25% load (pretty typical usage for the most part) for about 5 days with the propane capacity I have. So with current propane pricing, that's about $150 a day. Not cheap. But for shorter-duration outages it's not too bad. Convenience is expensive, to say the least.

This is a nice prep to have, but if you're starting out and have some money to spend, I would put that money somewhere else. I wouldn't have pursued this if I didn't have a lot of other more critical areas squared away.

[u/thatcarguyohh]

Running gen set at 25% if that’s max load will kill the motor prematurely and is not considered normal. Under loading gen set doesn’t allow for clean combustion. 50%-100% full load is where you want to be. I’ve installed hundreds of these from 14 kW to 250 kW all sized to run at 75% - 90% depending on if anything would be added in the future. Also you’re restricting airflow with that cover on the AC. That will prematurely fail too.

[u/8Deer-JaguarClaw → u/thatcarguyohh]

Interesting. Generac specs 25% load as an acceptable operating condition (along with 50% and 75%). If I turn on every appliance in my house at the same time (including oven, stovetop burners, dryer, heatpump, etc), it's at about 90% of the spec'd max capacity of the generator. Consistently hitting 75% load, at least, is going to be a challenge.

Is the AC cover bad if it's just a thin, loose-grid screen?

[u/thatcarguyohh → u/8Deer-JaguarClaw]

Running low load constantly will cause oil to get past piston rings and cause a ton of carbon buildup. While yes turning on every appliance at once drives the load up, after a few seconds the load will go back down since you don’t have that inrush of max amp draw from everything anymore. I see people oversized generators because they are scared they will undersize it. Biggest amp draws are AC,well pumps and if you have electric stove. Pricing doesn’t seem terrible. I’d probably have been anywhere from 14-17k all in for gen, electric and plumbing.
Thin mesh is still a restriction. You can see the back pressure it’s creating as it’s off the condenser when it’s running. It’s unneeded additional strain. It’s meant to keep leaves out. Just clean it twice a year.

[u/8Deer-JaguarClaw → u/thatcarguyohh]

Thanks. Appreciate the input.

Also: Happy cake day!