ISO/TS 25558:2026 — Smart Home Safety and Usability for Ageing Populations

The Ageing Imperative for Smart Home Design

According to the United Nations World Population Prospects 2024, the share of the world’s population aged 65 and over has nearly doubled over the last 50 years — from 5.5% in 1974 to 10.3% in 2024 — and is projected to double again to 20.7% by 2074. The number of people aged 80 and over is expected to triple during this period. This demographic shift creates an urgent need for technologies that support “ageing in place” — enabling older persons to live safely and independently in their own homes for as long as possible.

ISO/TS 25558:2026, developed jointly by ISO/TC 314 (Ageing societies) and IEC/SyC AAL (Active Assisted Living), provides comprehensive guidance on enhancing the safety and usability of smart home products, services, and systems for older persons. It recognizes that while smart home technologies offer tremendous potential — from voice assistants to automated fall detection — their adoption by older adults is often hindered by usability barriers and safety concerns.

The COVID-19 pandemic significantly accelerated technology adoption among older adults, but it also highlighted persistent gaps in usability and digital literacy. ISO/TS 25558 addresses these gaps through a structured, user-centred framework.

Understanding the Older Person: Health Status and Lifestyle

Physical, Psychological and Social Changes

The standard takes a holistic view of ageing, recognizing that health encompasses physical, psychological, and social dimensions that interact in complex ways:

Dimension	Key Changes	Impact on Smart Home Use	ICF Reference
Physical	Reduced vision, hearing loss, declined muscle strength, slower reflexes	Difficulty reading small screens, hearing alerts, operating touch interfaces	b210–b749
Psychological	Memory decline, reduced attention span, slower information processing	Difficulty learning new interfaces, remembering multi-step procedures	b110–b189, d130–d179
Social	Changed living arrangements, reduced economic power, narrower activity radius	Need for social connectivity features, cost-effective solutions	d710–d879, e410–e535

Lifestyle Continuum: From Independent to Fully Dependent

ISO/TS 25558 classifies older persons’ lifestyles along a spectrum using the Active Assisted Living (AAL) levels of assistance:

Level 0 — Independent: Able to live independently with minimal assistance
Level 1 — Some assistance: Occasional help needed, not on a permanent basis
Level 2 — IADL assistance: Help with instrumental activities (transportation, communication, shopping, medication management)
Level 3 — ADL assistance: Help with basic activities (walking, bathing, eating, dressing)

This classification is crucial because it directly informs the type and complexity of smart home solutions needed. A Level 0 individual might benefit from a smart thermostat and voice assistant, while a Level 3 individual requires integrated fall detection, behaviour monitoring, and remote caregiver alerts.

One size does NOT fit all in smart home design for older adults. The standard strongly emphasizes personalization — understanding each individual’s unique combination of physical, cognitive, and social capabilities, as well as their personal preferences and living environment.

Six Foundational Principles for Safety and Usability

ISO/TS 25558 establishes six basic principles that should guide all smart home design for older persons:

1. Self-determination: Older persons must be able to make their own choices and participate in decision-making about their lifestyle in smart homes. Even those with diminished judgment can often make decisions with appropriate support.

2. Personalization: Older persons are not a homogeneous group. Products and services must be inclusive, non-discriminatory, and tailored to individual characteristics — from tech-savvy early adopters to those with no prior smart home experience.

3. Privacy and security: Smart homes generate vast amounts of personal data. Explicit consent, data encryption, anonymization, and compliance with local data protection regulations are non-negotiable. Older persons must clearly understand how their data is collected, used, and protected.

4. Interoperability: Smart home devices must work together through standardized platforms. An older person should not need to manage five different apps to control lighting, heating, security, and entertainment — seamless integration is essential for usability.

5. Ethical aspects: The standard candidly addresses ethical concerns including privacy invasion, security threats, hacking risks, responsibility allocation in case of accidents, unequal accessibility, and the potential violation of human freedom and rights through monitoring or behavioural control.

6. User-centred evaluation: Solutions must be evaluated by actual older users in real or simulated contexts. Subjectivity, contextuality, and holistic perspectives are all essential to meaningful user experience assessment.

Practical Implementation Scheme

A Five-Step Process

The standard provides a structured implementation scheme for enhancing safety and usability:

Needs identification — Gather information from diverse perspectives: challenges, problems, personal experiences, family context, and environmental factors. The standard provides eight probing questions covering motivation, problem perception, timing, emotional response, daily disruption, values, health information, and unmet needs.
Selection considerations — Evaluate daily behaviour patterns, ensure intuitive operation, design appropriate user interfaces (physical, voice, visual, gesture), and guarantee security and privacy protection.
Application — Install and implement solutions that reflect individual needs. Solutions must remain stable despite changes in health or daily routines, and should support emergency detection, social connectivity, and cost-effectiveness.
User evaluation — Assess outcomes including usability, accessibility, user experience, and harm avoidance. Both subjective experience and objective performance metrics should be considered.
Iterative improvement — Use evaluation results to refine the smart home configuration as the older person’s needs evolve.

Engineering insight: The standard’s emphasis on ICF (International Classification of Functioning, Disability and Health) coding provides a powerful framework for linking health assessments directly to smart home feature selection. For example, an ICF code b210 (seeing functions) impairment directly suggests the need for tactile or auditory user interfaces, not just larger fonts.

Frequently Asked Questions

Q: How does ISO/TS 25558 relate to existing accessibility standards like ISO/IEC Guide 71?
A: ISO/TS 25558 builds on ISO/IEC Guide 71 and ISO 9241-11, applying their principles specifically to smart home contexts for older persons. It goes further by providing domain-specific guidance on the AAL levels of assistance and the ICF coding framework.

Q: Does the standard apply only to smart home products, or also to services and systems?
A: All three. The standard explicitly covers physical devices (smart speakers, sensors, appliances), digital services (telehealth, remote monitoring), and integrated systems (platforms that connect multiple devices and services).

Q: How can small manufacturers implement these guidelines without prohibitive costs?
A: The standard recommends a risk-proportionate approach. Basic usability testing with a small group of older users (5–8 individuals) can identify 80% of usability issues without the expense of large-scale trials.

Q: What about older persons with dementia or severe cognitive impairment?
A: The standard addresses cognitive status explicitly in Clause 7.1.3, noting that persons with cognitive decline may be unable to understand consequences of their actions or recognize risks. For this population, smart home systems should prioritize passive safety monitoring and caregiver alerts over user-initiated controls.