Efficiency has become an important focus in more ways than one. Architects design efficiently, workers aim to make the best use of their eight-hour workday, information technology seeks time-saving solutions and even Formula 1 racers are designing engines that squeeze every drop of fuel for the most power.

Doing more with less and maximizing value out of every morsel is not only expected, but required. 

Energy efficiency – there’s that word again – has long been a hallmark of the building industry. Homeowners and builders have strived for decades to get the most thermal comfort for the least cost. Frequently, more money upfront pays long-term dividends. 

Likewise, standard efficiency vs. high efficiency boilers is a frequent energy debate. There are instances where standard units are the better choice. However, for most building projects a high efficiency product might cost more initially, but will reduce heating costs and, over time, prove a much better value.

Multiple pass heat exchangers

High efficiency boilers usually have two, three or four pass heat exchangers that allow for the transfer of heat from the combustion process to water. Heat exchangers are used in both cooling and heating processes, and in more than just buildings. Heat exchangers are also found in air conditioning, petroleum refineries, natural gas processing and sewage treatment. 

Multiple pass heat exchangers allow the customer to save more money per BTU during this heating process vs. a single pass standard efficiency boiler. In terms of dollars, 80 percent efficient models are wasting 20 cents per dollar of BTU up the chimney. Ariston/HTP Elite Ultra Models, for example, with an efficiency of 96 percent, are only wasting 4 cents per dollar of BTU. The Department of Energy reports some older boilers have efficiencies in the range of 56-70 percent. High efficiency boilers range from 90-98 percent. 

It’s not just money that higher efficiency saves. According to the Department of Energy, upgrading a furnace or boiler from 56 to 90 percent in an average cold-climate house will save 1.5 tons of carbon dioxide emissions each year if heated with natural gas or 2.5 tons if heated with oil. In a world increasingly concerned about climate improvement, reducing carbon dioxide emissions is a significant objective. 

In addition, differences in venting and controls make high efficiency models more appealing to contractors and consumers. While subtle, controls to manage flue-gas composition, deposits and sequencing can shave heating costs. In maximizing efficiency, every little bit helps.

Case for standard

There are, however, applications in which standard efficiency boilers may be appropriate. In some cases, the application envelope will not allow highly efficient models to be installed in the location due to issues regarding gas delivery, venting or space. The constraints often have a price tag to correct, and consumers are unwilling to make costly upgrades for a high efficiency boiler. 

Another reason is the lack of education among consumers regarding the benefits of high efficiency boilers. Most consumers just want to replace the unit already in place because they do not fully comprehend the benefits such as return on investment or payback.

Comparing prices between standard efficiency and high efficiency models is hard to evaluate. Pricing is often determined by input or heating rates and is different across the United States. 

Smaller models will not have a large price gap between standard efficiency models and high efficiency models. On the other hand, high input rate models can vary by thousands of dollars. Contractors should look at the installation and customer needs to determine the best product for that job.

Rebates

Usually, rebates in local markets can help offset the upfront cost of high efficiency to close the cost gap between high efficiency and standard efficiency. The HTP website (htproducts.com), for example, includes a rebate center. By simply inputting their ZIP code, customers can determine what products qualify for a rebate.

The durability of components is not generally an issue. Most high efficiency boilers modulate, which is the ability to reduce its output. A 20-kw boiler, for instance, that only requires 10-kw of heat for the next hour will turn down its flame by 50 percent. The system will run much cooler and will require fewer stops and starts.

Modulation helps extend the life of the unit and ensures the right amount of power is being applied for the heating demand or call that is occurring. This will ensure the unit is not abusing the components by constantly over firing the unit. It also protects the heat exchanger. Starting and stopping leads to a boiler running hotter and cooler, which causes materials to expand and contract. That process creates thermal stress on components, especially in joints with dissimilar materials. 

While modulation extends the boiler’s shelf life, they do not last forever. Homeowners and businesses should have proper maintenance schedules, but should also check with the technicians to evaluate when replacement might be needed.

Frequently, owners wait until a boiler breaks down before replacing the unit. Failures often happen at the most inopportune time – such as when the houseguests are arriving for the Thanksgiving Day feast. Regular maintenance and monitoring by HVAC professionals can ward off unplanned, exorbitant boiler replacement costs. Watching for leaks, diminished thermal comfort and knowing the age of the boiler are important for owners to make proactive decisions about potential boiler replacement.

Comfort and budget

HVAC professionals on sales calls should discuss comfort and budget in evaluating which model to recommend. If there is a need for additional heating or domestic hot water needs, a bigger unit may be needed. A high efficiency model could deliver the same cost per BTU depending on the installation.

The potential budget could impact the decision as there are often modifications to installations that have to be made to replace a standard efficiency model with a high efficiency model. Again, most high efficiency boilers qualify for rebates that help offset this cost, but this is dependent on location. 

While standard boilers are still in use, the world’s commitment to climate change is gaining momentum and could make them a less desirable alternative. Already in England, the nation banned gas boilers from new housing in 2025 and households will no longer be able to purchase gas boilers beginning in 2035. Millions of homes throughout England will need to be retrofitted in the next decade. 

In the U.S., many product innovations are driven by the Department of Energy. As the DOE or government change efficiency regulations, appliance manufacturers are required to meet those requirements. Ariston’s view is “Sustainable Comfort for Everyone,” so high efficiency products are a primary focus.

In the final analysis, nearly all end-users should opt for the high efficiency models to provide the best return on investment. The unit will pay for itself sooner than standard efficiency models. 

High efficiency boilers make sense and save dollars over time. While upfront costs might be a burden, the money and energy savings across the lifespan of the boiler are worth the investment.

Ron Johnson, MBA, PMP, is the national training manager for Ariston Thermo in the United States. A graduate of Troy University, Johnson has more than 20 years in product management experience and has collaborated with multidepartment teams for plumbing and HVAC projects to design, develop, implement and evaluate new product introductions to solve market requirements.