Residential combined heat and power (CHP) systems can be harmful to health, Japan’s consumer affairs agency has claimed.   

The country’s Consumer Safety Investigation Commission reportedly said this week that the noise made by such systems, which is 200 Hz or lower, can cause health issues such as headaches and insomnia.

Spotlighted by the Commission were Japan’s two leading types of micro-CHP system, a gas-fired version sold under the Ecowill brand and a hydrogen fuel cell-based version sold under the rubric of the Ene-farm technology commercialization programme, which supports systems from all providers and has deployed over 120,000 residential systems in Japan to date.

According to Japanese media reports, the country’s Consumer Affairs Agency has received 73 cogeneration system-related health complaints since 2009 and the Consumer Safety Investigation Commission has investigated eight. In five of these cases, noise from the owner’s or a neighbour’s cogen system was found to be related to health problems.  

However, the symptoms reportedly varied significantly even between people living in the same house, from headaches and nausea to no measurable effects.  

In its report, the Commission suggested that noise abatement measures be taken and that consumers be told about potential problems.

The Ene-farm programme is a public-private partnership funded in part by government subsidies. From 2009 levels of up to ¥1.4m ($12,350), or half the cost of installing a residential unit, the subsidy has fallen to ¥500,000-600,000 and subsidies are planned to be phased out altogether at the end of 2018.

Meanwhile, sales of residential cogeneration units have roughly doubled each year since 2012. Leading suppliers include Panasonic, which holds roughly half of the market share, and Aisin Seiki Co. Toshiba bowed out of the residential market earlier this year, citing a desire to focus elsewhere.  

Japan has targeted the installation of 1.4 million residential cogeneration systems by 2020 and 5.3 million by 2030.