Objectives To assess the effectiveness of thermostatic mixing valves (TMVs) in reducing bath hot tap water temperature, assess acceptability of TMVs to families and impact on bath time safety practices.
Design Pragmatic parallel arm randomised controlled trial.
Setting A social housing organisation in Glasgow, Scotland, UK.
Participants 124 families with at least one child under 5 years.
Intervention A TMV fitted by a qualified plumber and educational leaflets before and at the time of TMV fitting.
Main outcome measures Bath hot tap water temperature at 3-month and 12-month post-intervention or randomisation, acceptability, problems with TMVs and bath time safety practices.
Results Intervention arm families had a significantly lower bath hot water temperature at 3-month and 12-month follow-up than families in the control arm (3 months: intervention arm median 45.0°C, control arm median 56.0°C, difference between medians, −11.0, 95% CI −14.3 to −7.7); 12 months: intervention arm median 46.0°C, control arm median 55.0°C, difference between medians −9.0, 95% CI −11.8 to −6.2) They were significantly more likely to be happy or very happy with their bath hot water temperature (RR 1.43, 95% CI 1.05 to 1.93), significantly less likely to report the temperature as being too hot (RR 0.33, 95% CI 0.16 to 0.68) and significantly less likely to report checking the temperature of every bath (RR 0.84, 95% CI 0.73 to 0.97). Seven (15%) intervention arm families reported problems with their TMV.
Conclusions TMVs and accompanying educational leaflets are effective at reducing bath hot tap water temperatures in the short and longer term and are acceptable to families. Housing providers should consider fitting TMVs in their properties and legislators should consider mandating their use in refurbishments as well as in new builds.
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Funding National Institute for Health Research, Accidental Injury Prevention Research Initiative (001/0009). The final study design, data collection and analysis, interpretation of results and paper writing was the sole responsibility of the authors. The views and opinions expressed in this paper do not necessarily reflect those of the funding body.
Competing interests MH is an employee of the Child Accident Prevention Trust (CAPT) which is a registered charity. ‘INTA’ a TMV manufacturer has previously sponsored a CAPT publication. There is the possibility that CAPT could benefit in the future by gaining sponsorship for other publications from TMV manufacturers.
Ethics approval Nottingham 1 NHS research ethics committee (reference number 05/Q2403/37)
Provenance and peer review Not commissioned; externally peer reviewed.