Selecting the Right Backflow Preventer Cover Heater

It's easy to overlook freeze protection when selecting a backflow enclosure for your reduced pressure zone (RPZ) backflow assembly . But if you don't take the proper steps to insulate and heat your enclosures, you could end up with frozen backflow prevention devices and huge problems.

Temperatures at or below 32°F can cause water in pipes, backflow preventers and other plumbing components to freeze and potentially burst unless they are properly insulated or heated.

A National Weather Service forecast map during the January 2025 Arctic outbreak showed that the vast majority of the contiguous United States experienced below‑freezing temperatures at the same time, with sub‑32°F readings covering almost the entire country except for some far-southern coastal areas. And according to Climate.gov, the last freeze of the season across most of the United States occurs on average after the first day of spring.

Backflow equipment that spends more than a day in freezing conditions can fail if its enclosure isn't heated. Part of the solution is installing a heater.

Heaters for backflow enclosures maintain freeze protection in the harshest environments. For maximum protection, the heater should be installed in an optimal location within the enclosure.

Types of Backflow Enclosure Heaters

When selecting backflow enclosure, consider the type of heater needed. Three types of available heaters are:

1. Self-Regulating Heat Cable

2. Wall-Mounted Heater

3. Slab-Mounted Heater

Each has unique characteristics, but keep in mind that all heaters are not created equal or protect the same way in cold weather. Here's a closer look at each option:

1. Self-Regulating Heat Cable

Self-regulating heat cables automatically adjust their power output to compensate for cold weather and temperature changes. When the ambient temperature drops, the cable's power increases and more heat is produced. Conversely, when the ambient temperature goes up, the cable's power output goes down and it produces less heat.

The self-regulating heat cable is wrapped around the backflow preventer and plugged into a power outlet. Most enclosure manufacturers offer the heat cable option for small-diameter pipes, typically 2” diameter and smaller.

2. Wall-Mounted Heaters

For backflow preventers larger than two inches in diameter, a heat cable may not be the best option for backflow covers. A wall-mounted heater is the next recommended heat option. In fact, most heaters in the industry are wall-mounted.

Safe-T-Cover's King Heater is a wall-mounted heater featuring a built-in thermostat. This heater meets the ASSE 1060 Class 1 standard for use in freeze protection. Note that most wall-mounted heaters are noncompliant with the ASSE standard because they are not UL wet/damp certified and simply are unable to deliver the most effective amount of freeze protection to keep your backflow preventer safe. 

Cons of Wall-Mounted Heaters

Wall-mounted heaters come with a few important limitations that may make them less safe and cost-effective than other options.

1. Wall heaters must be mounted to one side of the backflow cover due to doors and access panels.

2. Because most wall heaters are not wet/damp certified, they must be mounted at least 12 inches off the slab, leading to the next concern.

3. Heated air rises, so the warmth channels of the wall-mounted heater are heading straight to the top of the backflow cover long before uniform warmth is achieved. The objective of the heater is to keep the backflow preventer warm and offer freeze protection to the backflow prevention devices, not the top of the enclosure.

No one wants a backflow preventer to freeze. This is an expensive repair and affected building could be without water while the repair is made.

So what's the best solution for heating a backflow cover? The slab-mounted heater.

3. Slab-Mounted Heaters

A slab-mounted heater in an aluminum enclosure provides peace of mind because of its many features, including:

• Meets all ASSE 1060 requirements

• Provides heat to the equipment inside your aluminum enclosure as well as the riser pipes beneath the slab

• Will maintain an interior temperature of 40°F— even with an outside temperature as low as -30°F. 

Safe-T-Cover's patented slab mounted heaters are also certified for wet/damp conditions, which is necessary as an RPZ may dump water through the relief valve by design as a safety measure.

Why Slab-Mounted Heaters Are Best for Backflow Covers

Here's why slab-mounted heaters are the best choice for freeze protection.

The HCH Series Floor Heater bolts directly to the slab, producing radiant heat that penetrates 16 inches down into the vertical pipes. The system is also designed to withstand water spray conditions inside the backflow cover and meets the requirements of the UL-2021 section 49 rain test. Safe-T-Cover also doubles the roof insulation to R-18, which reduces the energy consumption of the heater.

As a design engineer, specify an ASSE 1060 Class 1 backflow cover with a slab-mounted heater You'll rest easy knowing the owner will never call and ask why the backflow device is frozen. Mother Nature surprises us all of the time — even Florida and Arizona freeze sometimes.

If you'd like more information on the type of backflow enclosure and heater you need on your next project, contact us and we'll be glad to help.