House generator questions...second thoughts on whole house system.

[drssg]

I wanted something that would be convenient, even if I was out of town. I can't expect my wife to drag the generator out of the garage, pull start it, and get things connected. Some years down the road, I might not be so good at it myself.

One night, there was a tornado warning in our area, and the path was coming very close to our house. We were in the basement watching the weather reports, when the power went out. It sure was nice to just sit there for a few seconds and then the power is back on.

I guess it comes down to a personal decision as to how much you'd rather use that $8000 towards something else.

 

[MGH PA]

The one major concern I have with a portable in unit is the inability to handle my geothermal heat pump. If we were to lose power in the winter, my only heat source would be my gas fireplace. That may not be enough depending on length of outage.

 

[Oaktree]

The one major concern I have with a portable in unit is the inability to handle my geothermal heat pump. If we were to lose power in the winter, my only heat source would be my gas fireplace. That may not be enough depending on length of outage.

Yeah, everyone's situation is different. We could go several days if we need to with just a portable to keep the refrigerator & freezer running, but if you have no source of heat, water, etc. if the power's off then it's a different story.

 

[Diggin It]

The one major concern I have with a portable in unit is the inability to handle my geothermal heat pump. If we were to lose power in the winter, my only heat source would be my gas fireplace. That may not be enough depending on length of outage.

There might be a possibility of using a second portable dedicated to that. But with the price of larger portables, you're getting closer to the base price of the standby. I've seen them at $1500+, though there are no install charges. Then again, you could get portables short term, install the standby later and sell the portables.

It's really a number vs. needs game with a convenience factor added in.

With the smaller standbys like mine, the manufacturer requires a shutdown every day to check oil. Not sure about the 24K unit you're looking at.

 

[hugo454]

since moving out here to the "country" from Fort Lauderdale,I had considered getting a diesel genset (military surplus diesel) because the Military spec ones are super quiet and most importantly,they operate at 1800 rpm versus 3600 rpm for natural gas(which I had in fort lauderdale).I currently have a gasoline 10,000 watt gen that is like new and was free.Been here going on 2 years and never lost power so I can't justify the cost of buying a diesel genset and "parking" it out back and never really needing it.
I also keep a "window shaker" air conditioner for hurricanes.I can cool one room in the house to sleep in comfort.
Been through 6 hurricanes to date, on the east coast for them all.

 

[s219]

I put in a 20kW diesel generator many years ago and we've never needed it for storms, knock on wood. Did use it last year for a planned 1/2-day outage when the power company was changing transformers on our road.

Prior to owning a generator at this house, we had several severe hurricanes with outages lasting 1-2 weeks at our old house. I still remember what that was like, and feel good knowing we are prepared here at the new house. Winter isn't so bad since we have a good fireplace with a lot of wood stored, but in summer heat/humidity, it can become unbearable real quick without A/C.

The beauty of diesel is that I can easily store enough fuel here for a couple weeks of operation running continuously (55 gal will give me about 5 days of continuous operation). That could be stretched out if we needed to. In fact, I don't anticipate we would run continuously if there was a real crisis. I would probably only run the generator enough to keep us comfortable and safe, and then we could go for many weeks, even months. I normally keep on hand 55 gallons in the generator's tank, and another 25-55 gallons in my transfer tank. I have spare drums to store another 165 gallons if needed. I can get plastic drums for $5 each locally.

Another nice thing about diesel is that I can cycle it through my tractor and RTV so I can keep rotating my supply. But with proper treatment you can store diesel a long time (longest I have gone is about 7 years with no issues).

We are all electric too, with geothermal, and part of my decision for diesel was realizing there was no need to have a propane tank at the house. Dealing with that just for a generator did not make sense to me.

I recall spending about $7K for the generator (ordered/shipped from Central Maine Diesel), and another $1K for electrical parts to install it (I provided all labor). If I remember right, commercial companies wanted about $15K to install the same setup (which included install pad/enclosure/tank, trenching, wiring, hookup, permitting, etc). It seems high, but after putting in the time/labor and doing the research to gain the expertise, I totally agree with their quoted costs.

If you go with a Generac propane generator, look into the water cooled units. They have a much longer service life and they run much quieter and cooler (1800 rpm versus 3600 rpm for the air cooled units).

 

[Ken45101]

A site with some good information and a simple chart for fuel consumption of propane generators.
CES | Backup Generators | Combined Energy Services

View attachment 716280
So a full 250 gallon tank would be good for 3-4 days possibly 5 for many people, rationing the run hours would lengthen that considerably.

I suspect that table is fuel consumption for a generator running under full load. If you are only running at a small fraction, I think the consumption would be significantly less.

 

[LouNY]

I suspect that table is fuel consumption for a generator running under full load. If you are only running at a small fraction, I think the consumption would be significantly less.

It most definitely would be less, I believe that table estimated 10KW for 103 hours on a full 250 gallon propane tank.
Even estimating consumption to be half of the 10 kw value you only have 200 hours on a 250 gallon tank.
Also when the situation is that you are in a widespread long term (10 day) outage you quite likely would not be able to obtain a refill.

Champion 100165 - 7500 Watt Electric Start Dual Fuel Portable Generator​

• Large 5.9-Gallon Extended Run Fuel Tank
• Provides up to 8 hours of runtime at 50% load
• 20 or 30-lb Tank Compatible (Not Included)
• Provides up to 7 hours of run time @ 1/2 load (20 lb.)

SO per this ad;
7 hours of run time on a 20 pound at half load,
so 3750 Watt for 20 pounds in 7 hours,
4.6 gallons divided by 7 hours yields 0.66 gallons per hr.

Then this one;

Winco HPS12000HE - 10,800 Watt Tri-Fuel Generator w/ Electric Start Honda Engine​

Rated Watts
10800 Watts
Surge Watts
12000 Watts
Fuel Type
LP/Natural Gas/Gasoline
NG Fuel Consumption @ 100% Load
200 ft³/hr
LP Fuel Consumption @ 50% Load
2.2 gallons/hr

So a 250 gallon propane tank with a 7500 watt at half load may make 300 hours
and a 10kw burning 2.2 gallons per hour at half load is only going 90 hours.

I expect that there isn't a lot of fuel consumption difference once you get much under half loads.
What surprises me is the high fuel consumption of the 10KW unit at half load.

 

[grsthegreat]

There might be a possibility of using a second portable dedicated to that. But with the price of larger portables, you're getting closer to the base price of the standby. I've seen them at $1500+, though there are no install charges. Then again, you could get portables short term, install the standby later and sell the portables.

It's really a number vs. needs game with a convenience factor added in.

With the smaller standbys like mine, the manufacturer requires a shutdown every day to check oil. Not sure about the 24K unit you're looking at.

honestly, every standby generator generally requires checking every 24 hours, more so with air cooled. i never find this an issue, as i have alot of customers who were away from home during long (5 day+) outages and never checked their units. they all functioned ok.

 

[grsthegreat]

It most definitely would be less, I believe that table estimated 10KW for 103 hours on a full 250 gallon propane tank.
Even estimating consumption to be half of the 10 kw value you only have 200 hours on a 250 gallon tank.
Also when the situation is that you are in a widespread long term (10 day) outage you quite likely would not be able to obtain a refill.

Champion 100165 - 7500 Watt Electric Start Dual Fuel Portable Generator​

• Large 5.9-Gallon Extended Run Fuel Tank
• Provides up to 8 hours of runtime at 50% load
• 20 or 30-lb Tank Compatible (Not Included)
• Provides up to 7 hours of run time @ 1/2 load (20 lb.)

SO per this ad;
7 hours of run time on a 20 pound at half load,
so 3750 Watt for 20 pounds in 7 hours,
4.6 gallons divided by 7 hours yields 0.66 gallons per hr.

Then this one;

Winco HPS12000HE - 10,800 Watt Tri-Fuel Generator w/ Electric Start Honda Engine​

Rated Watts
10800 Watts
Surge Watts
12000 Watts
Fuel Type
LP/Natural Gas/Gasoline
NG Fuel Consumption @ 100% Load
200 ft³/hr
LP Fuel Consumption @ 50% Load
2.2 gallons/hr

So a 250 gallon propane tank with a 7500 watt at half load may make 300 hours
and a 10kw burning 2.2 gallons per hour at half load is only going 90 hours.

I expect that there isn't a lot of fuel consumption difference once you get much under half loads.
What surprises me is the high fuel consumption of the 10KW unit at half load.

weve had long (10 day) outages in our area before. most people on generators have 500 gal tanks, I have a 1000 gal tank myself. Our propane company has never had an issue filling tanks during power outages...but it may take a day or 2 to get to us. I have a wifi tank monitor to keep abreast of my propane levels. Also, i would cycle the auto standby unit if i knew it would be a long outage. it does not need to run 24/7


the funny thing i have found is the larger generators will generally use less fuel than the smaller units, because on a colder day, the small units may need to run at full output continually to keep up with demand, while the larger units can run at a lower percentage of total output. i see mine running at 25% rated and use less fuel than a 7.5kw running full out