7 Commercial Heat Pump Myths: What Large Buildings Actually Need

Quick Answer: Why Are Commercial Heat Pumps Misunderstood?

A commercial heat pump is not simply an electric boiler that can be dropped into a plantroom without changing anything else.

Heat pumps transfer thermal energy rather than producing heat through combustion. That makes their performance particularly dependent on the temperatures they are asked to deliver, the heat source available, the building’s actual heating and cooling loads and the wider system around the equipment.

CIBSE’s AM17 guidance for large non-domestic buildings treats installations above 45kW thermal output as large heat-pump systems and dedicates substantial guidance to sizing, controls, electrical infrastructure, plant space, commissioning and system optimisation.

If you are new to the technology, start with our complete guide to commercial heat pumps in the UK.

Expert Contributor: Drew Maggio

Drew Maggio is Technical Director at HIGHMARK Building Efficiency in New York, where his work focuses on building electrification, decarbonisation and HVAC technologies for large buildings.

Drew shared his views with Heat Pump Guide UK on seven recurring misconceptions around heat pumps in larger buildings, drawing on his experience of commercial building systems and electrification projects.

His comments form the expert basis for the seven points below, with additional context and supporting guidance included for UK readers.

Myth 1: A Heat Pump Is Basically an Electric Boiler

This is one of the most important misconceptions to remove.

A boiler creates useful heat by burning fuel or, in the case of a direct electric boiler, converting electrical energy into heat. A heat pump works differently: it uses electricity to move thermal energy from one place to another.

Depending on the commercial system, that heat might come from:

• Outdoor air
• The ground
• Surface water or groundwater
• Another part of the building
• Cooling or refrigeration equipment
• A waste-heat source

That difference affects the way the entire heating system should be designed.

A boiler replacement based solely on matching the old plant’s rated output can therefore miss some of the most important questions: what temperatures does the building actually require, where can useful heat be sourced, and how does demand change throughout the day and year?

For air-source applications specifically, see our guide to commercial air source heat pumps.

Myth 2: Heat Pumps Are New and Unproven Technology

The idea that heat pumps are experimental technology does not reflect how widely the underlying refrigeration cycle is already used.

Air conditioning, refrigeration and heat pumps all rely on established vapour-compression principles. UK government policy also describes heat pumps as a proven technology that can be deployed in homes, larger commercial buildings and other applications.

What becomes more challenging in a large commercial building is not proving that the refrigeration cycle works. It is designing the right heat-pump system for that particular building.

Myth 3: Installing a Heat Pump Automatically Makes a Building Efficient

A highly efficient heat pump cannot remove the underlying heat demand of an inefficient building.

If a building loses substantial heat through its walls, roof, glazing, infiltration or poorly controlled ventilation, the heating system still needs to replace that lost energy.

Reducing unnecessary heat demand can therefore have two potential benefits:

• Reducing the amount of energy required during operation
• Potentially reducing the capacity of heat-pump equipment required

That does not mean every older commercial building must undergo a complete fabric retrofit before a heat pump can be considered.

Instead, building fabric and heating plant should be assessed together. In some projects, improving selected areas of insulation, airtightness or glazing could be more economical than designing the heating system around unnecessarily high heat losses.

Myth 4: If the Building Loses More Heat, Just Install a Bigger Heat Pump

Oversizing has historically been common in boiler systems, and an existing boiler’s rated capacity may be significantly higher than the building’s actual peak heat requirement.

That makes simply matching the capacity of the existing boilers a poor starting point for many heat-pump projects.

The better approach is to establish the building’s genuine heating and cooling demand and understand how that demand changes over time.

A commercial assessment may need to investigate:

• Peak design heat loss
• Annual heating demand
• Daily and hourly load profiles
• Simultaneous heating and cooling
• Domestic hot-water demand
• Required flow and return temperatures
• Part-load operation
• Existing emitters and distribution systems

Oversizing can increase capital cost and may also create poor part-load operation or excessive cycling if the complete system is not designed appropriately.

Our commercial heat pump installation and design guide looks at feasibility, load assessment, electrical infrastructure, procurement and commissioning in more detail.

Myth 5: Heat Pumps Cannot Really Be More Than 100% Efficient

Heat-pump performance can sound counterintuitive if it is compared directly with boiler efficiency.

A boiler converts fuel into useful heat. Its efficiency therefore describes how much of the energy entering the boiler becomes useful heat.

A heat pump is moving heat rather than creating all of it directly from the electricity supplied.

This is why heat pumps are commonly described using coefficient of performance (COP).

However, one COP figure should not be treated as a prediction of annual running costs.

Performance changes with source temperature, required heating-water temperature, load, defrost operation and auxiliary energy consumption. Seasonal performance is therefore more useful when estimating whole-year energy use.

For the financial side of a project, see our commercial heat pump costs and running costs guide.

Myth 6: The Main Barrier to Commercial Heat Pumps Is the Technology

In larger buildings, some of the most difficult issues can sit outside the heat pump itself.

Retrofitting an occupied office, hotel, school, healthcare building or residential block can involve considerably more than changing the main heating plant.

Current CIBSE commercial heat-pump guidance highlights many of these same issues, including electrical infrastructure, plant space, controls, distribution temperatures, commissioning and installer skills.

In other words, improving the equipment alone will not remove every barrier to commercial heat-pump adoption.

Myth 7: If a Project Underperforms, Heat Pumps Must Not Work in Large Buildings

When a commercial heat-pump project disappoints, it can be tempting to blame the core technology.

But the heat pump is part of a much larger system.

Performance problems can potentially involve:

• Incorrect sizing
• Unnecessarily high flow temperatures
• Poor emitter selection
• Hydraulic design
• Controls and sequencing
• Building heat loss
• Electrical or auxiliary loads
• Poor installation
• Weak commissioning
• Operating practices that differ from the original design assumptions

This is why commercial heat-pump projects need to be assessed as building-services projects rather than simple equipment purchases.

That distinction is particularly important when comparing commercial heat pump manufacturers. The product is important, but it cannot compensate for a poor system design.

What Should UK Building Owners Investigate Before Choosing a Heat Pump?

The seven misconceptions lead to a fairly simple conclusion: start with the building rather than the product brochure.

Before moving into detailed procurement, establish:

• What is the building’s actual peak heat requirement?
• How does heating demand change across the year?
• Is useful cooling required at the same time as heating?
• What temperatures do the heating and hot-water systems genuinely require?
• Could reducing heat loss lower the required plant capacity?
• Can existing emitters operate effectively at lower temperatures?
• What electrical capacity is available?
• How will the heat pump integrate with the BMS and existing controls?
• How will resilience and maintenance be handled?
• How will performance be measured after commissioning?

Only after these questions are understood does comparing particular products and manufacturers become genuinely useful.

Commercial Heat Pump Design Checklist →

Commercial Heat Pumps Are a Whole-System Decision

The strongest theme running through Drew Maggio’s comments is also one of the clearest themes in current UK engineering guidance: heat-pump performance is engineered, not guaranteed simply by selecting efficient equipment.

For large commercial buildings, the opportunity can be substantial. Heat pumps can provide heating, cooling and hot water, integrate with heat recovery and reduce dependence on fossil-fuel plant.

But the building, distribution system, operating temperatures, electrical infrastructure and control strategy all need to support the technology.

For businesses still at the research stage, continue with our Commercial Heat Pumps UK guide before moving into detailed system design or procurement.

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