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Propane standby generators, permanently installed in a home, are a vital piece of equipment for homeowners. Across the country, we see an increase in power outages due to strain on the electric grid or extreme weather. When power is lost, an installed generator can turn on within 10 seconds via an automatic transfer switch, so heating, cooling, lighting, and refrigeration are not disrupted.
Propane makes homes more resilient during a power outage because homeowners do not have to completely rely on the electric grid for power generation. Homeowners can use propane instead of, or alongside electricity, for space heating, water heating, and appliances such as stoves and dryers. For additional protection, permanently installed generators provide a quiet, efficient, clean source of power that can operate for weeks until power is restored, keeping your clients safe, secure, and comfortable.
Why Right-Size Generators for Residential Builds?
As a residential builder incorporating propane generators into your design plans, it is key to work with the generator manufacturer and possibly the local propane distributor to ensure the generator is sized right for the application. Many propane retailers also sell equipment, so you may wish to visit their showroom to get an in-person look at your options.
Right-sizing a generator will require calculating the generator power or total wattage required based on the appliances and systems it will power. Portable generators are best for powering critical appliances and max out around 17 kW — they are ideal for emergency backup power and recreational use. Standby generators are installed and permanently hardwired to the home and can power the entire home if sized property. They monitor for power outages and automatically turn on when needed. Standby generators for residential use are available up to 48 kW.
When critical systems such as space heating and water heating are fueled by propane or natural gas, the standby generator can typically be downsized — and made more affordable — because it isn’t running power-hungry electrical heating appliances. For example, an all-electric home will require a much larger generator that can generate more energy. But a smaller generator will work well in a residence with multiple energy sources such as electricity alongside propane water heating, space heating, and cooking equipment because the electrical demand is not so large. A furnace running on propane uses minimal electricity to power the blower motor.
Until recently, homeowners who wanted reliable power had to choose a few select applications that would remain running during a power disruption to avoid overloading the generator and burning it out. But improved generator load-monitoring technology makes it possible to keep power flowing throughout a home even as demand surges and shifts. If a generator gets to the point of overloading, the computerized load monitoring system that comes built into the switch will automatically shut off non-essential appliances and bring them back on when demand subsides. This provides a compromise to larger liquid-cooled solutions, although you give up some of the “all on” capabilities.
Performing an Energy-Consumption Audit
To calculate the correct size of generator needed, you must know the following:
- Square footage of the home.
- Central air conditioner size, in BTUs or tons. Air conditioners use the most wattage of any other appliance, so the generator must be able to handle the AC load when required.
- Whether you want to power the whole house during a power outage or specific appliances. The more appliances you want to use, the greater demand for electricity, therefore the bigger the generator you will need.
- Again, electric appliances such as a water heater, dryer, and range will add to the load required.
- Running vs. starting wattage.
Calculating running vs. starting wattage
To calculate running wattage, first add all the “running watts” for appliances that will be powered by the generator. This number will be the total running watts. Next, add the single highest starting watts out of the appliances you want to power. These are appliances such as furnaces, refrigerators, and sump pumps that require an extra boost of power when they turn on. The starting wattage may be up to 3x the running wattage. Finally, add the total running wattage and the highest starting wattage from an individual item to get the total starting watts needed.
1,500 SQ FT Residence – Example Energy Demands and Generator Needs
In different climate zones across the U.S., all-electric homes require generators anywhere from one-third to twice as powerful and expensive as homes using both electricity and propane. For customers interested in whole-home standby power, choosing propane appliances where possible such as a water heater, furnace, cooking appliance, and clothes dryer will allow them to cut the capacity and cost of their whole home generator, compared with an all-electric home. This can equate to thousands of dollars in savings. In a 1,500 square foot residence, a home run on propane can operate on a 14 kW generator at an approximate cost of $4,867, whereas an all-electric home requires a 22 kW generator at an approximate cost of $6,247. *Note that there are many variables to consider and this example is only provided to give an idea of varying energy demands in a similar sized residence and how they can impact generator size.
Resilient Propane Standby Generators
Now that you know how to right-size a generator based on the energy use in a home, you can help clients understand the importance of emergency power and choose a propane standby generator ideal for their needs. Installed and permanently hardwired propane standby generators contribute to resilient design and will keep their heating, cooling, lighting, and refrigeration running without disruption.
