About: http://webisa.webdatacommons.org/391169744

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Profesionaly put together systems have a pay back period of around 20 years (unless there is a fairly large swimming pool to be heated then it is about 5 or 6 years).
http://www.w3.org/ns/prov#wasQuotedFrom	diydoctor.org.uk