Thermostat Wars: Why Women Really Do Feel the Cold More at Home and What That Means for Energy Efficiency

It’s a modern domestic battleground: one partner reaches for the thermostat, the other rolls their eyes. On our forums and on podcasts, it’s a recurring theme (the so-called thermostat war) and while it often prompts laughter, the underlying issues run deeper than personal quirks. Our recent poll combined with emerging scientific insights, suggests that the battle over home temperatures has meaningful consequences for energy use, gender equity and heating system design.

We asked 150 households across two polls: who likes it warmer? The combined results were telling:

• 64% said the female partner prefers it warmer
• 12% said the male prefers it warmer
• 24% reported no difference

This pattern mirrors existing research on gendered thermal preferences, and now, for the first time, we can explore how this plays out in UK homes transitioning to low-carbon heating systems such as heat pumps.

The Physiology Gap in Thermal Comfort

A 2015 peer-reviewed study in Nature Climate Change by Boris Kingma and Wouter van Marken Lichtenbelt highlighted a fundamental flaw in how indoor temperatures are calibrated. For decades, the standard thermal comfort model (PMV/PPD) has been based on a single, uniform metabolic rate: that of a 70 kg, 40-year-old man at rest. However, real-world measurements show that women’s resting metabolic rates are typically 20–35% lower.

Why does this matter? Lower metabolism means less heat generated internally, particularly when at rest… the state many people are in while reading, watching television or working from home. The result is that women often feel colder in the same room than their male counterparts. The Kingma study found that women’s preferred temperatures are, on average, 2.5 to 3C higher than those preferred by men .

Undermining Energy Efficiency at Home

In an era of energy-conscious living, this discrepancy introduces a critical challenge. UK homes are increasingly being designed and retrofitted to achieve optimal energy performance, but if the baseline design temperature doesn’t match real-world comfort requirements, households may adapt in counterproductive ways.

Many heating systems, especially heat pumps, are configured to deliver 21C in living spaces, a temperature cited by the NHS and used in SAP assessments. But if a significant portion of occupants (particularly women) are not comfortable at that temperature, they are likely to take matters into their own hands.

These adaptations often include:

• Using plug-in electric heaters, which are typically less efficient and more carbon-intensive than central heating.
• Layering up with heated throws and electric blankets, increasing plug load demand.
• Closing internal doors to create warmer microzones, which may restrict healthy air circulation and affect humidity levels.
• Manually adjusting thermostats or smart controls, pushing heating systems to work harder and reducing seasonal coefficient of performance (SCOP) on heat pumps.

These behaviours may restore individual comfort, but they can erode the promised efficiency of the overall heating system, especially if zones are overheated or if manual overrides become habitual. In the long term, they can also drive up running costs, undermining the affordability benefits often cited in favour of heat pumps.

Is 21C Enough?

This raises an important question: is 21C truly sufficient for real-world comfort in decarbonised homes?

For some, yes. For others, particularly those with lower metabolic rates, the answer is no, especially during periods of sedentary activity. The biophysical analysis in the Kingma study identified a “biophysical thermal comfort zone” for women ranging from 23.2C to 26.1C, depending on factors such as body composition, clothing and skin temperature .

This is not to say every room in every home should be heated to 25C. But it does challenge the prevailing assumption that a one-size-fits-all setpoint delivers universal comfort.

Designing for Diversity

If we want homes to be both efficient and equitable, we need to move towards more flexible and inclusive heating strategies. This might include:

• Zoned heating systems that allow for warmer bedrooms or living areas tailored to individual comfort, which is contrary to the current trend of open loop systems.
• Smarter controls that learn user patterns and adapt without users needing to override them.
• Occupant-led commissioning that ensures comfort is trialled and verified post-installation, not assumed at handover.
• Public awareness campaigns that move away from moralising thermostat settings (“turn it down to save energy”) and instead focus on comfort strategies that don’t undermine efficiency.

As heat pumps become standard in UK homes, it’s essential that heating engineers, designers and policy-makers recognise the diversity of physiological needs in the population. The 21C benchmark, while useful for modelling, is increasingly insufficient as a comfort baseline, particularly for women older adults, and others with lower metabolic heat production.

Comfort, after all, should be universal, and in the pursuit of energy efficiency, we can’t afford to leave half the population out in the cold.