Winter road during a snowstorm. Image via

Standby Generators Start Harder in the Subfreezing and Subzero Cold Winter Weather

As cold winter weather arrives throughout a good portion of the United States, people hurry to purchase new car batteries and fill windshield fluid reservoirs.

Cold weather in these regions is nothing new. The Northern Plains, Upper Midwest, Ohio Valley, Northeast, and Mid-Atlantic States often experience temperatures below zero. Below freezing temperatures are quite common in the Rocky Mountains and central portions of country. Whether you love, hate, or even just tolerate it, the winter season requires more preparation in many aspects of life.

This is the time of year to service furnaces and home heating systems, put out holiday decorations, and look forward to that winter vacation at a warm sunny beach or a powder-covered ski slope

Don’t forget your standby generator when it comes to seasonal maintenance and preparation. Over the winter, a home backup generator will keep the furnace running through power outages and prevent your pipes (and your family) from freezing. In addition to scheduling regular maintenance, keep your standby generator clear of snow and ice and ensure that the air intake vents don’t become clogged or blocked by debris.

Replace Old Batteries

Home Backup Generator Vents and Surrounding Area Cleared of Snow and Ice After a Snowstorm

Keep Your Home Backup Generator in Good Working Order After it Snows

A marginal battery during the summer and fall may not seem like an issue. Every week the standby generator wakes up and starts its exercise cycle. All seems well, despite controller alerts that the battery is near the end of its life. Now that winter has arrived, that marginal battery may not have the power to start the engine when temperatures fall below freezing.

As the temperature drops, the chemical reactions within the battery that produce electric current take place at a lower rate than during warmer temperatures. The colder it gets, the slower the reactions. A battery near the end of it’s life or one that has seen above average use might not have all the energy it needs to start the engine during cold weather.

The battery will probably fail during a cold spell just when you need it most—a power outage during and ice storm at two o’clock in the morning is not the time to realize your battery can’t start the engine in cold winter weather. If your battery is near the end of its expected life, or if the controller tells you it is time to replace the battery, purchase a new, quality battery and have it installed.

Change the Oil

A Briggs & Stratton Preventative Maintenance Kit

Maintenance Kits with Filters and Other Parts Keep your Generator Running.

Colder temperatures may require a lower viscosity oil for easier starting. In the summer, a higher viscosity oil works well to lubricate the engine, but in the winter that oil might be too thick. Changing to a dual viscosity oil will provide easier starting.

If the generator’s manufacturer allows or suggests, a dual viscosity synthetic oil may allow easier starting in the winter and still provide the required lubrication and protection in the summer. It’s important to check your owner’s manual or call the generator manufacturer before switching to a different oil viscosity. Never use an oil that isn’t recommended by the generator manufacturer.

Change the oil filter every time you change the oil. Dirty oil doesn’t lubricate as well and a clogged oil filter reduces the flow of oil in the engine. Maintenance kits contain all the necessary filters and parts to keep your standby generator engine running. Keep a couple on hand to see you through an extended outage.

Battery Warmers

A Generac Battery Warmer.

A Home Backup Generator Battery Warmer



Batteries produce electricity through a chemical reaction. The strength of that reaction is partially dependent on the temperature of the battery. As temperatures fall, the amount of current the battery is capable of producing declines.

In cold weather climates—and that means anywhere the temperature drops below 32 degrees Fahrenheit—a battery warmer is the most basic cold weather accessory you can purchase. A thermostat automatically senses when the battery temperature drops below a set temperature and turns on the warmer to keep it warm.

If you live where temperatures fall below thirty-two degrees, a battery warmer is an inexpensive option to ensure reliable starting.

Cold Weather Kits

Cold Weather Kit for 16kW and 20kW By Briggs and Stratton

Cold Weather Kits Ensure Smooth Starting in Below Freezing Weather

Some standby models allow the addition of other accessories to ensure easy starts in cold weather. Oil warmers and block heaters help keep the engine warm for easier starts, but should always be paired with a battery warmer if one is not included in the kit.

A cold weather kit is a necessity anywhere the temperature falls below 32 degrees. If it does not include a battery warmer, purchase one separately. Cold weather kits may change the oil type or viscosity required. Generac’s Extreme Cold Weather kit for their liquid cooled engines require the use of synthetic 5W-30 oil.

Even if you live in the south where temperatures are usually above freezing, ice storms and other weather events that last just a few days can make engine starts more difficult. The cost of a cold weather kit is cheap insurance.

Updated by MJ Logan on 12/15/2017