There is a huge range of generators on the market today, with many different price points and features. In this guide we’ll explain everything you need to know before making a purchase so you know exactly what to look for in order to find the perfect generator to fit your needs.
Portable or Standby (Fixed)
The very first decision you need to make is whether you need a permanently fixed standby generator which can power your entire home in case of a power outage, or a portable model.
A portable generator should be able to keep some of your home essentials running but will not usually have the power to run every appliance in the home. But of course, being portable they have many other uses such as for RV’s, camping, tailgating, music festivals and much more.
If you have power outages at home on a regular basis, you may wish to invest in a standby generator. These need to be professionally installed by an electrician and are much more expensive than portable generators. If you think you will require the standby type, it will be best to contact an electrician directly as you cannot install these yourself.
On this website, we deal just with portable generators, but much of the information in the rest of this buying guide will be applicable to either type.
Determine your power requirements
A generator runs on a fuel source such as gasoline, propane or diesel and is able to output a certain wattage for some period of time. You then plug your appliances into the generator in order to feed that power to them.
What is important to understand is that anything you plug into your generator will have its own specific power need. A large fridge is going to need a lot more wattage than a cell phone charger for instance.
Generators some in different power sizes. Generally speaking, the more power they provide, the more they cost. So when you estimate your power requirements, you should also take into consideration your budget.
You’ll need to determine the requirements for each appliance that you wish to plug in. You find find estimates online for various types of appliances which can give you a ballpark idea but it is better to check your individual items and check the labels.
There are various points to consider such as what the running wattage is, as well as the start wattage, how to convert to amps and so on. We have a separate guide to calculating wattage.
There are two factors that determine how long your generator will be able to run for:
- The size of the fuel tank
- The load you are running it at
Every generator will have a tank which holds the fuel required to actually generate the power. The bigger the tank, the longer the generator can run for.
The load means, what percentage of the power you are actually drawing from it. For example, if you have a 3,000 watt generator and you plug appliances into it that draw 1,500 watts, it is operating at 50% load. Generally speaking, it is best to run it at half load than to try to push it to capacity because surges could cause it to overload and thus damage both the generator and whatever you have plugged into it.
Manufacturers will usually give an estimated run time based on the load. So it might say, ‘7 hours at 50% load’. So be aware of that and if it mentions a particularly long run time, check to see what load they are referring to. Some manufacturers will deliberately use lower load times to be able to say how long lasting their generators are, when in reality, most people would be running at a much higher load.
Number of Outlets
An outlet is a receptacle on the generator into which you plug something in. Large home appliances such as fridges and freezers will need to be plugged directly into an outlet. However, if you are running very small items such as a phone charger or a lamp, you could use an extension cable that provides multiple plug sockets. If you do this, you still have to calculate the wattage of every item that will be attached.
Most generators some with 2 or 4 outlets. If you wish to run a number of large appliances you will need one with a higher number of outlets.
One other point to consider with regards to the outlets is their voltage. For large appliances you will need a 240v outlet but some of the smaller generators only have 120v outlets. Others have a mixture. You will again need to assess what your individual needs are to determine what will be sufficient.
If you are purchasing a generator as a backup for your home, then mobility will not be very important as you will most likely place it into a dedicated enclosure near (but not too close to) the house.
However, for uses where you need to take the generator out with you such as for camping or tailgating, then mobility will become a lot more important! They are typically very heavy, and the larger the tank size and the larger the power output, the bigger and heavier they will be.
There are three factors to consider:
- Overall weight and size
- Folding handles
Many portable generators now come with a wheel set meaning that you can just pull it along rather like an item of luggage. Smaller ones usually just have handles for you to carry them which fold away afterwards. Even with these features, you should still consider the weight and size, especially if you need to lift it – into the back of a car or an RV for instance.
Some generators can be extremely loud which could be a major problem. For example, there are many campsites that have a restriction on noise level and you may not be able to use your generator if it is too loud.
The noise output is measured in decibels. Anything over about 60 dB and you will definitely notice it. Whilst there are some ways to reduce the noise of some generators by using accessories and building soundproof enclosures for it, if you think the level is going to be a problem you are much better off paying a bit more and buying a quiet generator instead.
Most generators will need to be started (turned on) via of the following mechanisms:
- Rope & Pull start
- Electric start
The rope and pull is just what it sounds like; there will be a handle attached to a rope which you will need to pull on firmly in order to start it. You may need to practice this a few times to get a feel for the right amount of pull to use.
An electric start generator will have either a button to push, a switch to flick or a key to turn. Whichever type it is, it will be a very simply on/off mechanism which is extremely easy to use.
The electric start ones are certainly easier to use but they operate from a battery and of course it then becomes crucial that your battery is fully charged otherwise you may not be able to start your generator when you need to! Rope and pull generators do not have this problem.
There are some generators that actually have both mechanisms. You can use the electric start most of the time, but if the battery is not sufficiently charged, you have the pull rope as a backup.
You will want to look at all the factors above in any generator purchasing decision. Some will also come with various other features which are listed below. Some are just for convenience but others are much more important safety features which you should be on the lookout for.
Manual Fuel Shut-Off Switch
For most people, their generator is going to be spending most of its time in storage and only be used on occasion. It needs to be properly stored and a manual switch to shut off the fuel will prevent any fuel leaks.
Low Oil Shut-Off
Generators need to oil to run, much like a car, and they must not be allowed to run out as that would cause it to seize up and cause irreparable damage. Most generators have an automatic shut off if the oil level gets low to prevent this disaster.
Another related nice feature is an indicator letting you know that it shut off due to low oil levels, rather than being out of fuel, or having an excessive power load.
As discussed earlier in the article, the amount of fuel in the generator determines how long it can run for. A fuel gauge will simply allow you to see how much you have left at any one time which is much better than having it simply shut down because it ran out of fuel.
There is a lot to think about before buying a generator and it is certainly worth spending a little time doing your research up front. It is especially important to properly calculate your energy requirements as if you buy a generator with too low an output, you’ll end up wasting your money and having to buy a second one or upgrade to a bigger one!
Do also pay attention to the safety features, the mobility of the unit and the noise level because mistakes in these departments can make the difference between a generator that makes you miserable or one that is a joy to use!