Are electric systems in your future?

By Bob “Hot Rod” Rohr

I am not convinced anyone on the planet knows how this electrification movement will shake out. Some well-meaning but not well-informed desk jockeys have put a stake in the ground. My opinion is deadlines to go 100 per cent electric will continue to be pushed out, or modified.

In the meantime, however, it presents an opportunity for hydronic pros to learn new methods and products.

Simple Technology

Electric boilers are not new. Both hot water and steam boilers have been and are available. On a smaller-scale, electric steamers for the shower are basically a mini-steam boiler, of sorts. Electric point of use DHW heaters, while not ASME listed, could be considered electric hydronic “boilers.”

With the possible exception of a kettle over a campfire, electric boilers are perhaps the simplest technology to heat water. Consider the well-known electric tank type water heater. It incorporates an immersion resistance element and a few thermal disc temperature and safety controls. It’s really just a handful of components screwed into and onto a plain steel tank.

Additional temperature and pressure protection is provided in the form of a temperature and pressure relief (T&P) valve. The T&P protects for temperature in excess of 210°F and/or pressure in excess of 150 psi. It is not too big a step to make a safe, legal and smart electric boiler based on the immersion resistance element.

A quick online search reveals electric boilers appeared in Europe around 1905. Electric boilers differ from electric water heaters because they have more control and safety options. The vessel itself will typically have an ASME pressure vessel stamp.

Controls and limits are a bit more adjustable and may include staging control to step in the elements. Modern electric boilers may be controlled by triac relays as opposed to magnetic contactors, which could be noisy and maintenance prone. Additional control features might include outdoor reset function and Bluetooth enabled options. You could consider an electric boiler to be an electric water heater on steroids.

Determining Actual Cost

The biggest question is the operating cost when considering electricity as the heating fuel source. Looking at a power bill, it can take some math to really determine the actual cost of a delivered Kwh. Many bills show the cost per Kwh, but also add on multiple charges such as customer service, distribution, transmission, line loss adjustment, and so on. To find the accurate cost divide the total cost by the actual meter reading. This applies to all fuels. LP, NG also will have additional fees applied.

In some areas, utilities looking to better manage their generation capacity offer discounted rates for evening or early morning use. I have found examples of residential rates dropping to 1 cent per Kwh. With this in mind, adding a storage component can help you leverage some extremely low electricity rates for heating loads.

Insulated buffer tanks can be used as thermal storage. Or, in some cases, loading a concrete slab with heat during off-peak rates can give you enough of a flywheel effect to coast through the peak Kwhs. It is worth asking questions about off peak rates as they benefit you and the utility company.

Another popular concept is using solar photovoltaic (PV) to offset some electricity costs. There are all sorts of online calculators to determine if this makes sense in your area. Feed-in tariff (FIT) programs can be an ever-moving target. Shop carefully. My experience shows the door-to-door PV salesmen have a different view of payback compared to experienced PV designers and installers. Find a knowledgeable person to help you sort through PV options.

 A good fuel cost comparison spreadsheet is at the coalpail site

Maintenance and Troubleshooting

I’ve not come across a mechanical or electric-mechanical device that does not require some maintenance and occasional service. When looking at the simplicity of a resistance element device, troubleshooting involves a simple multimeter and the training to use it correctly.

Granted, the more complex electric boilers with microprocessor controls can be more complicated to troubleshoot. However, many computer-based controls will do some basic troubleshooting for you. Error codes tell you where to start looking for a fault. You can map out the settings to call or text you an error alert. The tools required to properly service mod cons are considerably more expensive.

My opinion, knowing the fickleness of the energy market, would be to consider a hybrid approach. If the customer currently has gas or LP, advise them to keep it. Calculate if and when electricity is the better cost option. Controls are being developed that can watch electricity costs in real time and select when to go 100 per cent electric.

Power grid operators may make a decision for you regarding power availability. Many electric appliances allow the power company to monitor usage and control available power. They may brown out areas of high draw. Having a fossil fuel source, perhaps with a small generator back up, will help prevent customers from being left out in the cold.

Movement in Full Swing

It’s easy to find a chat room or webinar talking about the ins and outs of electrification. Follow the hydronic sites in North America, but also in the UK and Europe where the electrification movement is in full swing due to the instability/uncertainty in global fuel availability.

This year’s AHR show in Chicago, IL, certainly proved that the hydronic players, boiler manufacturers included, are fully onboard with electric hydronic heat source options.

There are so many things to think about these days with energy costs, as well as product offerings. Start learning the pros and cons of the options so you can knowledgeably present options to customers.

Don’t be intimidated by the move toward an electric future. Embrace the opportunities and get ahead of the curve.

Bob “Hot Rod” Rohr has been a plumbing, radiant heat and solar contractor and installer for 35+ years. A long-time columnist, Bob is involved with training and education at Caleffi North America. You can reach him at [email protected].

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