Generator and propane tank sizing feedback needed

[rbstern]

We've just begun grading for our new home on our rural property. It will be a 2000 square foot ranch on a daylight basement. It will be propane fueled for heat, hot water, and stove, with 200 amp electrical service for everything else. My plan has always been to have a generator available for backup power. It's time to start making some decisions about how that generator will be sized and fueled.

At the low end of the pricing spectrum, I could simply get a Harbor Freight 7000/8750 watt gas fired generator, rig a 30 amp connection box with a breaker panel lockout setup. In my current home, I have a 4000/5400 watt Generac that I run inside a Rubbermaid shed, with 12v marine fans powered by the generator for exhaust and intake air. Actually works very well and the generator runs cool. It has a great muffling effect. Go more than 75 feet away, and you can't tell there is a generator running. I would probably use the same shed for the HF generator.

Next step up would be the same HF generator, with a propane conversion kit, plumbed to the house propane tank, or with it's own propane tank.

The above two setups are nice in terms of being able to lock up the generator in the garage and wheel it out during extended outages, although at 200+ pounds, it's a beast to move around, even on wheels. If my wife had to do move it, I'm not sure she could. It could live permanently in the Rubbermaid shed, and I could chain it down to concrete, to prevent theft. The limitation is the 30 amps. Would have to power only essential circuits

Stepping up from there would be a whole home/standby type setup, with power levels and transfer automation priced to suit. Pricing anywhere from $2500 to $5000 for what we would need, not including the propane tank and hookup costs.

And that bring me to propane tank issues:

My original thought was to buy an oversized propane tank for the house. A 250 gallon tank is normal for single family dwellings with the heating requirements in our part of the country (north Georgia). A 500 gallon tank would certainly be a big step up. But that's an expensive upgrade, with a much bigger hole to dig. Alternatively, I could buy a second, smaller tank, maybe a 200lb. tank, which I can probably find used and dig/bury/install myself, right near the generator installation. While that might limit the generator to a couple of days run time, it would also be a hedge against running through the whole 500 gallon tank in case of a leak or other problem.

Lots of choices, which is a good thing. Of course I want to economize, but at the same time, I hope to be in this house for at least 20 years, so it's a small dollar per year issue.

Comments appreciated.

 

[techman]

An 8KW will burn about 1.7 gal/hr at full load. On average figure 50-60% of that for an average house load. Make sure you have the line and regulator sized for full load (about 155,000 BTU/hr).

paul

 

[ning]

We've got 2 x 1000g tanks, above ground. The house has a swimming pool with a propane heater, and the house is heated by propane (depending on our use of the wood stove).

We don't use the swimming pool any more (barely ever did - don't put one in is my advice, but swmbo...), and we fill up on propane once a year and typically get 700-800 gallons (ie, we end up swapping tanks each year). This gives us complete flexibility to try and get the lowest possible cost for propane in the year; we have a good relationship with a local supplier who notifies us when they think the pricing is best (and we keep an eye on prices as well, and we rarely miss out on more than a penny a gallon).

If you can afford it, get more storage than you think you'll need in a year. You'll save in the long run, and there's great peace of mind having extra.

(Don't get me started on people who own their place and rent a tank from Amerigas and get topped off each month and the highest possible prices.)

 

[Deere Dude]

(Don't get me started on people who own their place and rent a tank from Amerigas and get topped off each month and the highest possible prices.)

I won't get you started but the gas company topped mine off one year just as the corn dryers were sucking gas. For what should have cost 59 cents cost me 1.39. The next month gas was down back to 59.

Why bury the tank? Aesthetics?

 

[RNeumann]

Good generators list their fuel consumption per hour at idle and load. Only you and the family can decide how much extra you need. Remember propane tanks are only good to about 80% rated capacity.
If you go the full automatic route you will need a means of disconnecting the auto start if you are away for several days.

We have a 1000 gal tank for our gen, water heater and stove.

 

[rbstern]

We're on a lake, so a swimming pool would be redundant. I have enough trouble keeping the boat clean. Keeping water clean, too? No thanks.

I very much want to own the tanks and buy propane from who I want.

 

[rbstern]

Good generators list their fuel consumption per hour at idle and load. Only you and the family can decide how much extra you need. Remember propane tanks are only good to about 80% rated capacity.
If you go the full automatic route you will need a means of disconnecting the auto start if you are away for several days.

Good point. Easy enough to rig a battery disconnect terminal.

 

[RNeumann]

We have ours on a secondary thermostat that would only turn it on if temp dropped below 40°f and the power was out. With a programmable thermostat it will do its weekly maintenance run too.

 

[rbstern]

We have ours on a secondary thermostat that would only turn it on if temp dropped below 40°f and the power was out. With a programmable thermostat it will do its weekly maintenance run too.

Makes perfect sense for where you are. Freeze damage is a VERY remote possibility here.

 

[rustyshakelford]

We buried a 500 gallon tank. Would do it again tomorrow if needed. I think they tanks are ugly. When you bury it, you have to buy it. That has allowed me to get the best price by shopping around.

Our house is a little under 2800 sq ft. Single story with 30' roof height. Gas stove, instant water heater, furnace and pool/spa. We use around 200 gallons a year.

Brett

 

[RNeumann]

Makes perfect sense for where you are. Freeze damage is a VERY remote possibility here.

Has little to do with freezing. My transfer switch now requires power loss and the thermostat to start the gen. If I'm away it won't start unless certain programmable perimeters are met. It would be a waste for the gen to automatically start and run for hours or days if I'm not around.
However, it's nice to know the gen will start and run daily, weekly etc (if programmed that way) to keep the refer cold and or keep the house from freezing or ?????

 

[rbstern]

and or keep the house from freezing or ?????

Does that not count as freezing?

 

[RNeumann]

Does that not count as freezing?

Your ignorance and arrogance is beyond belief! You started the post and asked the question. I provided my experience- actual experience- this is what I get? You want to take a few words out of a multi paragraph post and try to spin it? It certainly takes all kinds........

 

[rbstern]

Your ignorance and arrogance is beyond belief! You started the post and asked the question. I provided my experience- actual experience- this is what I get? You want to take a few words out of a multi paragraph post and try to spin it? It certainly takes all kinds........

Whoa! I think you mistook my meaning. The little icon I pasted is supposed to mean "confused." As in...I am confused by your answer. You described your thermostat control solution as having little to do with freezing, but you described keeping the house from freezing as one of the reasons for the solution. I figured there might be two meanings to freezing (something to do with the generator vs. the house). I was looking for clarification.

So, yes, I am guilty of ignorance, because I clearly didn't know what you meant with your freezing reference. But arrogant? For seeking clarification? Geez, I hope not.

No offense was intended. I do appreciate your comments in response to my original post.

 

[mmancuso13]

Don't forget which ever way you go that typically tank loads are 80% of the tank size. So a 500G holds 400G more or less (it all depends on the placement of the tank vent which can vary slightly tank to tank).

Based on everything you have mentioned I think you would be better off with a fixed auto transfer type system. It will be a one and done install, the cabinets do a fair job at sound suppression and best of all the misses does not ever have to do anything in the event of a power outage. The only down sides have been mentioned - more up front cost.

Because you described a situation where your homes annual propane usage is not too large you could always elect to put in one large tank (500 or preferably a 1000G - buried or above ground) and run everything off the single tank.

I have 2 1000G tanks - one for the house and one for the Gen and the advantage (also previously mentioned) is the ability to fill propane just once a year when summer prices are low.

My tanks are purchased but I have not had any issues purchasing propane form whomever is cheapest. Many companies will try the old, "we have to come out and pressure test the tanks before we fill them" to which I reply not on my $ you don't. It's mostly a crock, all they need to do is check the tank dates to make sure they are within the revert window.

Anyway good luck whichever way you go!

 

[mmancuso13]

Hey just my two cents on the rant above me... maybe the OP did not get the concept of your integrated exercise control (time and temp) but I doubt he meant any disrespect in his response. All is well, have a drink and relax!

 

[rbstern]

Don't forget which ever way you go that typically tank loads are 80% of the tank size. So a 500G holds 400G more or less (it all depends on the placement of the tank vent which can vary slightly tank to tank).

Based on everything you have mentioned I think you would be better off with a fixed auto transfer type system. It will be a one and done install, the cabinets do a fair job at sound suppression and best of all the misses does not ever have to do anything in the event of a power outage. The only down sides have been mentioned - more up front cost.

Because you described a situation where your homes annual propane usage is not too large you could always elect to put in one large tank (500 or preferably a 1000G - buried or above ground) and run everything off the single tank.

I have 2 1000G tanks - one for the house and one for the Gen and the advantage (also previously mentioned) is the ability to fill propane just once a year when summer prices are low.

My tanks are purchased but I have not had any issues purchasing propane form whomever is cheapest. Many companies will try the old, "we have to come out and pressure test the tanks before we fill them" to which I reply not on my $ you don't. It's mostly a crock, all they need to do is check the tank dates to make sure they are within the revert window.

Anyway good luck whichever way you go!

Thanks for the extensive comments. I am leaning toward what you suggest.

With that much propane on hand, do you worry about a propane mishap? Not so much fire/explosion, but a leak that could lose a thousand or two bucks worth of propane?

 

[mmancuso13]

No worries on that, code typically requires buried lines to the Home for both above ground or buried tanks) and once the tank is installed and the lines pressure tested you will not have any issues.

Also a typo above the tanks ha e a recert time window not a revert window...

 

[rbstern]

No worries on that, code typically requires buried lines to the Home for both above ground or buried tanks) and once the tank is installed and the lines pressure tested you will not have any issues.

Also a typo above the tanks ha e a recert time window not a revert window...

I was thinking more about a fixture, like a BBQ grill with a propane feed coming from the house to the outside. Case in point, the wind grabbed my BBQ grill one day, threw it across the deck. It took up the slack of the 6' flexible hookup hose and yanked hard on the copper line coming from the house, bending it. The line has a valve in it, and it was closed, but the bend was below the valve. Fortunately, it' didn't split the copper. The copper line is now more securely fastened to the house, and I am more cautious about securing the grill during a storm.

Nobody was there at the time. Had the line split, whatever was in the propane tank would have vented to the open air.

 

[mmancuso13]

That is true! If you use any portable devices with propane you should make sure they are not too portable! Maybe an eye bolt to he deck or wall and a bike chain to show the grill who's the boss...