for a relatively cheap and minimal work temperature and humidity sensor check out the xiaomi bluetooth temperature and humidity sensor and use the Pis bluetooth to query it. circa 18months of use from a singe aaa cell
https://zsiti.eu/xiaomi-mijia-hygrother ... pberry-pi/
if using Node Red, the Node-red-contrib-xiaomi-ble node will query/interface with the device given its mac addy.
if determined to hack a solution i would suggest an esp32 module over an esp8266 due to its superior sleeping capacity and lower power use.
tho the wemos-d1 esp8266 and its plug in shields do make it fairly 'lego'
However avoid the dht11 sensors and spend the extra £ to get a dht22, afaik its both more accurate and has a longer operational lifespan.