In the future, it may be possible for systems to dynamically select from electric or gas heat based on operating efficiency and rates at any given time.

Climate-Resilient HVAC Can Handle the Potential for More Frequent and Extreme Weather Events

Climate change doesn’t just bring higher average temperatures. It also contributes to higher precipitation and less predictable global weather patterns. This could place demands on systems that exceed today’s design values for high and low temperatures and high humidity.

With that said, I don’t advocate excessive oversizing to accommodate these changes. Instead, I prefer performing careful load calculations and evaluating different systems to see how they may handle temperatures that are a bit higher or lower than the design.

Many modern inverter systems can operate above their maximum rated capacity when called to do so.

Higher temperatures and sea levels also mean more atmospheric moisture and higher dehumidification loads in some areas.

After a big rainstorm or hurricane, elevated humidity could cause mold or bacterial growth. Consider adding dedicated dehumidification in places where it gets sticky outside.

Provide Essential Services in an Extended Grid Outage Event

Whether the power goes out due to excessive grid demand, a weather-related issue, or some other reason, it’s never fun to suffer without heating or air conditioning for long periods.

If a power outage coincides with a winter storm or extreme cold snap, failing to plan for backup heat properly can become hazardous or even life-threatening.

For all-electric systems, backup generation needs to be appropriately sized to handle not just the running load of the heat pump (plus any other connected loads), but also the starting load, which can be several times higher than the running load.

Inverter units or the addition of a soft start can significantly reduce generator capacity requirements. Always use inverters if a customer plans to run the system on a generator or battery backup.

Dual-fuel systems dramatically reduce backup power requirements – all that’s needed is a small portable generator to run the furnace blower and controls.

Climate-Resilient Systems Can Provide Clean Indoor Air and Prevent Biological Growth Due to Excess Humidity

With the potential for higher and more frequent high-humidity days comes an increased risk for mold and bacteria to take over a home. That means you must seriously consider the impact of dehumidification loads.

Doing an “extra” load calculation for peak dehumidification loads is prudent. Climate change also increases the occurrence and severity of wildfires, bringing smoky and unhealthy air.

Where wildfires are a concern, MERV-13 or higher filtration can keep indoor air from reaching unhealthy particulate levels and protect occupants from long-term health issues.

Don’t forget to assess the pressure drop from higher MERV filters when selecting equipment and scoping duct upgrades.These are all considerations for you as you design climate-resilient HVAC systems.

The New Gold Standard

Modern climate-resilient heat pumps hold a ton of potential for helping to reduce emissions from burning fossil fuels. However, this widespread shift to electric heating coincides with many challenges, from weird weather to possible grid instability. In this environment, broadening design considerations and installation practices to meet the above goals protects your customers, your reputation as a high-performance contractor, and even society.

Climate-resilient HVAC will become the new gold standard in High-Performance HVAC contracting in a world that will continue to warm and change for the foreseeable future.

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Ben Lipscomb, P.E. has more than 16 years of experience in the HVAC industry, including laboratory and field research, Design/Build contracting, and utility energy efficiency program design. He is National Comfort Institute’s director of engineering and utility programs and may be contacted at ncilink.com/ContactMe.