China＇s　aging　population　is　growing　rapidly.　To　date,　there　have　been　few　literatures　concerning　indoor　environment　of　private　houses　with　older　people.　This　study　fully　investigated　indoor　environment　in　10　houses　(5　urban　and　5　rural　houses)　with　older　people　during　heating　season　in　Beijing,　China.　Each　house　was　assessed　for　temperature,　relative　humidity,　CO2,　PM2.5,　CO,　NOx,　formaldehydes,　acetaldehyde,　VOCs,　SVOCs　and　fungi.　Results　indicated　older　people　in　urban　houses　experienced　a　steadier　and　warmer　thermal　environment　than　those　in　rural　houses,　due　to　the　difference　of　heating　devices　between　urban　and　rural　houses.　Indoor　CO2　levels　mainly　increased　up　to　1000　ppm　in　the　bedroom　during　sleeping　time.　For　rural　houses,　indoor　fuel　combustion　contributed　to　an　extremely　high　PM2.5　and　CO　level.　Formaldehyde,　acetaldehyde,　toluene,　ethylbenzene　and　xylenes　levels　in　most　houses　were　lower　than　the　limit　values.　However,　the　integrated　influence　of　these　compounds　was　unnegligible.　TVOC　concentrations　in　four　measured　houses　exceeded　the　reference　value　of　600　mu　g/m(3).　The　most　frequent　fungi　was　Cladosporium　spp.　(90%),　followed　by　Penicillium　spp.　(70%)　and　Aspergillus　spp.　(60%).　The　fungal　levels　in　rural　houses　were　higher　than　urban　houses.　These　results　will　be　beneficial　to　improve　housing　environmental　quality　for　older　people　in　China.　(C)　2018　Elsevier　B.V.　All　rights　reserved.