On July 21, 2010, I signed a contract with Quality Generators to install a Generac Guardian 20 kW natural gas-fueled automatic standby generator. This is a project that I've been hemming and hawing over for the last three years, and I finally decided to bite the bullet and do it. After our experiences with Hurricane Ike back in 2008, this seemed like an excellent investment to make in the house not only for adding to the resale value of the house, but also for the comfort and convenience factor. When Ike blew through, my folks and I were significantly more prepared than most people. We had three portable generators (a 5.5 kW Briggs & Stratton and two 2 kW Hondas), two small air conditioners (a 12,000 BTU Sunpentown portable and an 8,000 BTU GE window unit), and all of the requisite extension cords, power bars, etc. We were comfortable and able to run our entertainment center, two refrigerators, a deep freeze, a couple of laptops, and all of the lights we wanted to run (thanks to using CFLs). But it was still a major inconvenience - and potentially hazardous. We stockpiled 75 gallons of gasoline in the garage to feed the portable generators. The Briggs generator was noisy - and a fuel hog. The portables needed to be refueled at constant intervals, and we had extension cords everywhere.
Enter the automatic whole-house standby generator. As I mentioned, I'd been considering one for years, and I finally had the financial wherewithall to pull the trigger and get one. After much research, I decided the 20 kW Generac unit would run everything - and I mean everything - I would want to run during an extended power outage. And that includes both of my central air conditioners. Every appliance in my home that could be natural gas-powered uses natural gas: the heaters/furnaces, the water heater, the clothes dryer, the stove, the oven, and my outdoor grill are all natural gas. If they made a dishwasher with a natural gas dryer in it (rather than the electric heating element), I'd buy one of those, too. My large-wattage appliances are the central air conditioners, the microwave, the dishwasher and, to a lesser extent, my entertainment equipment.
One of the factors in installing a generator is the placement of the genset itself. Many are placed as close as possible to both the gas meter and the electrical service panel when possible. Luckily for me, both of those items are exterior and right next to each other. However, the problem is that they're both outside my back yard fence. Besides the fact that I would've had to get my homeowner's association involved if I placed it there, placing it outside the fence didn't seem the best option in terms of security for the unit. I don't really want to visibly advertise to passersby the fact that I have a standby generator. The other thing is that placing the generator near the meters would have put it (and its accompanying noise) too close to my bedroom. Instead, I decided to place the generator in the back yard about 35 feet from the back of my house along the west fence, and next to the detached garage of my neighbors. This gets the noise away from the house and my bedroom, and puts it so that noise shouldn't disturb the neighbors.
With the site chosen, a little bit of preparation work was necessary. I had to remove a bush and build up the area where they would be pouring the pad. One call to my yard guy got it all taken care of. He removed the bush and trimmed back the adjacent bushes on both sides to give the required lateral clearance (three feet on both sides). He then brought in some good stable dirt - the type they use under home foundations - and built up the pad area about 8 inches. While I believe I would need to build an Ark if my back yard flooded (due to the elevation of my yard along with the drainage system back there), with the amount of the investment to have this unit installed, I thought building up the area to ensure it never flooded out was a prudent step. Anyway, my yard guy removed the bush and built up the dirt area on August 3.
On August 9, Quality sent out their concrete crew to pour the pad. The guys really had a good system down (and the right tools) to whip out the pad in less than an hour. Not too bad since the pad required 15 bags of Quikrete. The pad is three feet deep by five feet wide by six inches thick, with some small-gauge rebar for reinforcement. Below are some photos of the process to this point.
On August 17, the plumbers from Quality came out. They set the generator on the pad, dug the trench for the natural gas fuel line, and got everything plumbed in. Here are some photos of the generator set on the pad and plumbed up.
On August 26, Centerpoint Energy (the local natural gas utility) came out and upgraded my gas meter. Due to the "thirstyness" of the generator, the pressure needed to be upgraded. Typically, the regulator on the service entrance side of the meter downgrades utility line pressure from 30 - 50 psi to between 4 and 6 ounces of pressure before delivering the gas into the house. Due to the volume of fuel required by the generator and other natural gas appliances, a pressure increase is needed to make sure that a) the generator isn't fuel starved, and b) other gas appliances aren't fuel starved while the generator is in operation. Every appliance in my house that has a natural gas option uses it: water heater, furnaces, stove, oven, clothes dryer; even my grill is connected to the natural gas supply (never have to refill propane bottles!). If they had a natural gas option for the dish washer's dry cycle, I'd have one of those, too! By upgrading the pressure at the meter, it will ensure that even if the generator is running full bore, I will still be able to cook, dry clothes and take a shower with hot water without risking starving any appliance or the generator of fuel to do its job. The upgrade cost $350 and included new regulators and a brand new meter. It took the Centerpoint man just shy of 2 hours to undo and re-plumb everything. With that step complete, the final step is the electrical wiring and installation of the transfer switch.
On August 27, the electricians from Quality showed up to do the electrical work. This piece of the installation involved digging another trench for the conduit that would house the phase cable and control wires. I was under the impression that the control wires had to be run in a separate, smaller conduit; however my electrician said that was only the case for larger phase cables (they used 3 AWG copper) or if the phase cable wasn't THHN-rated. So everything runs in a single 2" PVC conduit buried about 18 inches deep.
The next step would have been mounting and wiring the transfer switch and 150 amp main disconnect (more on that in a sec). However, we ran into a snag. Centerpoint (also the local line delivery utility) has electric meter locking rings on the meters, along with a tamper lock. The electricians can't (didn't want to?) remove the lock, and no one had told me I needed to contact Centerpoint to have that removed. I called them early Friday morning, but a service person didn't show up until almost 6:00. The electricians got as much done as they could and made arrangements to come back on Monday the 30th.
On the 30th, the electricians arrived again to finish the installation. They mounted the main disconnect and transfer switch and did as much pre-wiring as they could before popping the meter out and killing power to the house. They were pretty efficient - power was out maybe 20 minutes as they moved connections from the meter to my original service panel and wired in the new panels. The main disconnect is necessary because my house has 150 amp service, and the main breaker on the transfer switch is rated at 200 amps. In short, a smaller capacity breaker (the 150 amps) in the main disconnect is required so that nothing in the house is overloaded due to the higher amp breaker in the transfer switch. I still have the 150 amp main breaker in my original service panel, too.
For some photos of the finished electrical project:
Once the panels were in place and wired up, power was restored to the house, and the guys finished installing buried conduit and pulling the load and control wires from the generator to the transfer switch. Sort of like putting together a puzzle, they hooked every wire where it needed to be, both in the generator and in the transfer switch. They also hooked up some control wires from the transfer switch to each of my air conditioner compressors. A neat feature of my transfer switch is the capability to give certain loads priority over other loads. This is also known as load shedding capability. Even though my generator is large enough to handle both of my AC compressors at the same time, should something place a large load on the unit, it will shut down one of the AC units so that the generator isn't overloaded. It also spaces out the starting of the compressors. Right after the generator starts, the transfer switch begins a timer that will not let either of the AC units start for 5 minutes. This allows other loads in the house to fire back up and get stabilized to their running current/amps. After 5 minutes, it will start the higher priority air conditioner and let it get stabilized before allowing the second compressor to start. All of this is regardless of what the thermostats are telling the units to do. In the end, the load is spread out over a little more time so that the generator isn't overloaded when everything wants to start back up at once.
With everything wired in, it was time to fire up the generator for the first time. This was accomplished by moving the switch inside the generator from Off to Manual (it will live in the Auto position most of the time). Since this was the first startup, and the natural gas pipes had been disconnected for the meter upgrade, it took several attempts for the unit to finally catch and start. Once it did get started, it ran just fine. They let the unit run - with no load - for about 5 minutes before shutting it down. At this point, we were ready to test it out.
The easiest way to fully test to make sure the unit is running is to simulate a power failure by making the transfer switch think utility power has been lost. This can be done with the main breaker in the transfer switch, but I can also do it by turning off the 150 amp breaker in the main disconnect box, as it sits between the meter and the transfer switch. Anyway, they killed the main breaker in the switch. I counted off about 15 seconds, and then the generator automatically started. About 10 to 15 seconds after that, the transfer switch switched the load from the regular service entrance side to the generator side, and the generator took the load. Beautiful! We let the unit run about 15 minutes, and we tested it further by putting the load of both of my air conditioners onto the generator. Let me tell you, it runs GREAT! Whenever one of the AC units starts, the different UPSes (Uninterruptable Power Supplies; battery backups for my computer and TV equipment) I have around the house "bark" at the mini-brownout. But once the AC is fully started up, everything is back to normal.
The generator is louder when running than I was expecting it to be, so I'm definitely glad I placed the unit as far away as I did - it is about 35 feet from the back of the house. Also, due to the orientation of the generator and the side of the house it is on, the exhaust and cooling ports point towards the house. For noise mitigation, the best place to put it would have been behind my detached garage. My home backs up to a bayou, and putting it back there would have shot the noise in that direction. However, due to some future plans I have to expand my garage, plus the extra distance and cost associated with putting it there (the run would have been close to 85 feet rather than 35 feet), the place where it lives now is a good compromise. Either way, I would recommend that if you're considering a unit like this and expect that at some point it might have to run for several days (or weeks...) that you place it as far away from the house as you can afford. I have great custom windows on this house that really reduce noise levels from outside, so that helps a lot. You can definitely hear the unit running from any room that faces the back yard. My master bedroom is on the front of the house, and I can barely hear it running. In the other front room, you can't hear it at all, and I know a lot of the lack of noise is due to the great windows. If you have older single pane windows, again, place the unit as far from the house as is practical and affordable.
A Few Updates
Now that the generator has been in place for a couple of years, I thought I'd post a little bit of information on actual use, and also address a couple of comments and questions I've received, both in this site's comment section and via e-mail. First, I'll address cost. The generator and installation was a turnkey job by Quality Generators. It wasn't cheap - about half was the cost of the generator/transfer switch, and the rest was labor and materials. The only extra expenses were the add-on remote controller for the generator (but it was rolled into the cost of the job with Quality), the gas meter upgrade, and then the pad site dirt build-up and bush removal. I don't remember exactly what I paid my yard guy for for his part - maybe $150 - $175. This will vary, though, depending on your situation. The gas meter upgrade was a flat cost of $350 payable to Centerpoint, the gas utility. Having them come out to pop the lock on the meter was a no-cost visit. But here's the big number, and don't let it find you looking for oxygen or the defibrillator, because there's a lot involved in getting one of these things installed and operational. The cost of the turnkey job (including the remote controller) was $10,400. But this was inclusive of everything except the pad site preparation and the gas meter upgrade. It included the pad, the generator, the transfer switch, and all of the labor to get it all installed, hooked up and working. There was some extra cost involved because of the distance away from the gas meter and the electric service panel. They give you up to a certain amount of feet away from the utilities, and then charge by the foot from there. I think the given distance is 30 feet, and then beyond that they charge (or were charging) about $30 per foot combined for both gas line plumbing and electrical.
To put this price in perspective, go shopping around on the Internet, and swing by Home Depot (they sell Generac units, too). ElectricGeneratorsDirect.com shows my 20 kW unit with transfer switch for $4,497. That is just the generator and transfer switch, nothing else. So the rest of the price I paid was labor and materials. They dug the trenches for the gas line and electrical conduit. They poured the pad and mounted the generator to it with bolts into the pad. Their plumbers did all of the gas line hookups, and their electricians did all of the wire-in at the transfer switch. Can someone do some or all of this himself? Sure! The concrete work isn't all that big a deal. Digging trenches sucks, but is doable. However, some areas have to meet code, and if you have to have permits and meet code to get all of this done, a professional installation is highly recommended and may be your only option. I considered doing all of the work myself as a cost-saving measure. I probably could have done it for around $6,000 - $6,500. But I'm not a master electrician, and while the wiring portion of the installation isn't rocket science, it can be pretty compex to a novice - and there's the high voltage stuff you have to contend with. While I could have done some of the plumbing of the gas line myself, because it is natural gas, I'm happy to let a licensed plumber do that, too. The project would have taken me multiple days, even weeks, to finish, and all in all, even though their stuff was spread out over a couple of weeks and a several visits, actual work time involved for them was maybe three days. So after weighing everything out - and knowing I have a company with a service department to call should I have a problem - I decided to cough up the extra dough and have the installation done professionally.
Speaking of the service department, I've been glad to have them - on one occassion specifically. Turns out my unit came with a faulty throttle body on the engine. I lost power here one evening around Memorial Day in 2011. The generator fired up and ran for about 40 minutes that evening. My upstairs air conditioner then kicked on. In response to the added load, the controller in the generator commanded more throttle, and the connection point where the throttle push rod connected failed. The generator was then not getting enough fuel to carry the load. The generator sputtered under the load, reached what it thought was an overload condition, and automatically shut down. Luckily, the power was out for only 20 or so more minutes after the failure. Anyway, I called Quality, they came out the next day and diagnosed the problem, and they handled all of the warranty work and the entire repair. It was nice to be able to make that one call and have everything taken care of. Since then, the generator has run flawlessly during several other relatively short-duration power outages. Just a few weeks after the repair was made, a transformer blew down the street, and I was running on the generator for almost 7 hours while the utility made repairs to their grid. It was June and already hot, and it was really nice to have the AC going and everything working as normal through the outage.
Another question I've received a few times is some confusion on the need for a gas meter upgrade. Is one really necessary? The answer to that varies. How many other natural gas appliances do you have in your house? How large is the generator you're looking at? Smaller generators can get by without a meter/pressure upgrade. However, larger engines require more fuel to run, so with larger units, a service/meter upgrade is essentially mandatory. My 20 kW generator is right on the cusp of maybe/maybe not needing it under normal circumstances. However, as I mentioned a couple of times earlier in this article, I have a lot of gas appliances. I want to ensure that they all work in an extended outage and that the generator isn't fuel starved at any point due to those other appliances being in use. All of those factors together, I chose to upgrade the service. Have a look at this pre-install/post-install schematic I've thrown together for a better picture (pardon the pun) of what you're dealing with.
Most appliances in the home require low pressure in the gas line. This includes your furnace(s), water heater(s), gas cooktop/stove, gas ovens, gas clothes dryers, grills, etc. Basically any gas appliance you use in your home is made to run on low pressure, ounce service (the only potential exception to this that I can think of is the larger on-demand tankless water heaters - those things require a pretty hefty supply of gas). As seen in the diagram, most of the time the pressure delivered into the home after the gas meter is between 6 and 8 ounces of pressure per square inch - roughly 1/2 PSI, or pound per square inch. Notice that that is a huge step-down in pressure from what's delivered to the service entrance side of the meter. The meter itself, however, does no pressure regulation - all it does is measure the volume of gas that passes through it. The regulators are what steps the pressure down from high to low pressure. Most of your typical home-installed meters are made for use with the lower pressure, thus the regulator being on the entrance side of the meter. The other item here for consideration is volume and pipe size. Typically, gas pipes post-meter might be one inch diameter, and then stepped down to 3/4", or even 1/2" in some cases, for final delivery to the appliance. The key here is that larger pipe means more volume. The gas line on the utility-side of the meter is typically 1.5", but they make up for that size (could be small by some standards) by delivery at such high pressure.
Now, enter the generator. The fuel requirements of the generator will vary with brand, model and size/capacity. Suffice it to say, though, that the generator will become the largest consumer of natural gas you have when it is running. According to the specifications for my generator, it will consume 206 cubic feet of natural gas per hour at half load, and 294 cubic feet per hour at full load. The gas company typically bills out by the CCF. One CCF is 100 cubic feet of natural gas, and roughly equivalent to 100,000 BTUs (British Thermal Units), or one Therm, of energy. So for billing purposes, and energy-usage purposes, my generator at 1/2 load will consume 2.06 CCF of natural gas per hour. At full load, it will consume 2.96 CCF per hour. When both of my air conditioners are running, I estimate that I'm probably around 60% or so of load.
To put this further into perspective, let's compare that hourly consumption by the generator to the amount of gas I typically consume in a normal month. By "normal," I mean that the generator has not had to run under load during a power outage, and it only runs its weekly 12 minute no-load exercise cycle. During the summer, I typically consume between 6 and 10 CCF for the entire month. During the winter, depending on how cold it is, my monthly consumption jumps to between 50 and 70 CCF for the month. That's the equivalent of 2 - 3 hours of generator cosumption for summertime, and roughly a day of runtime for wintertime consumption. Also, to further put it into perspective, I anticipate the generator will cost me between $40 and $50 per day to operate during an extended outage. That's just the direct natural gas fuel cost, and doesn't include anything for maintenance.
So in short, you see that the generator needs a healthy supply of fuel. The fuel needs to be available at the proper pressure and at the proper volume to meet demand of all of the connected appliances and equipment. Even though a regulator at the generator steps the higher 2 PSI pressure down again to home entry-level pressure - roughly 8 to 10 ounces of pressure - the 1.5" gas supply line from the meter to the generator running at 2 PSI ensures that the generator has plenty of fuel pressure and volume, and that it is never fuel-starved while under load. That higher pressure also ensures that none of my other gas appliances are fuel starved, either, even though the connection for them is plumbed in after the large 1.5" line for the generator. This ensures that my water will be hot, that I can do laundry, and can cook on any of my gas appliances without worry of them or the generator running out of fuel.
Again, as mentioned above, the 20 kW generator is right on the edge of being able to run on regular low pressure delivery. But for only $350, I figured it was worth it to upgrade the service and never have to worry about things running out of fuel. Better to be safe than sorry!
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