The Safe-T-Cover Blog

Comparing the Different Heaters for Backflow Enclosures

Posted by Craig Carmon on December 7, 2017

For climates where the temperature can fall below freezing for a few days a time, adding a heater to the backflow enclosure is basically common sense. It's one of those decisions that could fall into the penny wise, pound foolish categories. The cost to add a heater to the enclosure is not a big financial decision with the most expensive options costing no more than a few hundred dollars. Old man winter rolls in and markets like the Carolinas, Texas, and everywhere in between can be hit with cold weather that can last a week at a time or longer.

What happens if a heater wasn’t specified for the enclosure and the winter cold blast comes in for a few days? If water isn’t moving through the backflow device, as is common overnight, freezing could occur which will cause damage. This now damaged backflow valve costs several thousand dollars and may not be in stock at the local plumbing or water works distributor. Now when water is needed, it is not available and that’s when the decisions will be asked about why heat was excluded.

The question, "Should I include a heater with my enclosure?" is an easy one to answer - in most cases it's a "Yes." Instead, we'd like to answer the questions many customers have about the different heaters for backflow enclosures that are available. The four most widely known aluminum enclosure manufacturers offer different types of heaters. They work and are installed differently. Here’s an overview of what each manufacturer offers.


The Aquashield® website describes its heaters as meeting ASSE 1060 standards, but it is not clear which class they meet. However, they describe their heating options as being UL or ETL tested for wet/damp conditions. This is in keeping with other manufacturers. Safe-T-Cover's heaters are UL listed while Hot Box® heaters are ETL listed. There is little public information on Aquashield® heaters, but they are offered in 1000 watts and 1500 watts as shown on drawings. They have an aluminum casing, a fan-forced heater, and must be mounted above the discharge valve of RPZ backflow preventers. This manufacturer also offers a heat cable for smaller applications.

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This manufacturer offers a heater that is attached to a bracket which spans the width of their enclosures. Each of their enclosures has a matching heater that has been factory fitted to the enclosure. The bracket is mounted just above the slab, with the topmost elbow of the heater 12.5" above the slab. The heater comes in sizes ranging from 800 watts to 1800 watts and in 120 and 240 volts. These heaters are ETL listed for operation in damp or wet conditions. This manufacturer also offers a heating cable for applications 2" and smaller.

Hot Box®

Like most backflow enclosure manufacturers, this one offers both wall mounted heaters and a heat trace tape which can be wrapped around the equipment. Hot Box®'s literature says that their heaters for backflow enclosures meet ASSE 1060 standards. The heater must be mounted above the discharge point of an RPZ backflow preventer. The heaters are available in various wattages with most between 1000 and 2000 watts. They have been ETL tested for wet/damp locations. The heat tape is very similar to the cables that are offered by Safe-T-Cover, AquaSHIELD®, and other manufacturers. It is available in 30, 60, and 90 watts.

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Safe-T-Cover is the only backflow enclosure company offering a heater which is mounted directly to the concrete slab. This design provides heat to the slab and riser pipes and heats the enclosure where the heat is needed, at the device. Wall mounted heaters keep the top of the enclosure nice and warm but cannot provide the same level of certainty that the temperature at the backflow device will be the same as the setting of the thermostat. Heat rises, and if the thermostat is above the device which needs protection, it is less reliable than a thermostat below the device. Check out this short video on how our heaters for backflow enclosures work.

The slab mounted heater is UL2021 listed for operation in wet or damp environments which is a requirement of section 1.2.3 of ASSE 1060 for class 1 enclosures. The class 1 designation means the enclosure will maintain a temperature of 40 degrees F even when exposed to outside temperatures of -30 degrees F. The slab mounted heater comes in three different sizes: 500, 1000, and 2000. All three sizes are available in 120V. The 1000 watt and 2000 watt heaters are available at 240V at no additional charge. The heater is mounted directly to the slab with concrete wedge anchors. You can find detailed submittal and installation instructions for each of our heater options online. Here is an example. We also offer a variety of wall mounted heaters in 500, 1000, and 2,000 watt sizes, and a heat cable with 5 watts per foot is available as well. You'll find all our heater options here.

Get The Heat You Need

When specifying an enclosure in climates where winter conditions could cause freezing, be sure to call for an ASSE 1060 Class 1 enclosure. Be sure the enclosure manufacturer offers a heater that is listed for wet/damp environments as an enclosure can become damp from water discharge from test cocks and from an RPZ relief valve discharge. Remember - not all heaters are the same. The slab mounted heater is the best option for keeping the backflow device and riser pipes from freezing. We've written even more answers to your questions about enclosure heaters here.

aluminum enclosure

Topics: Enclosures, Backflow Preventers