A question or two for the services inclined:
SAP currently assumes that heating circulation pumps, based upon traditional technologies with a 65 W pump running for 2000 hours per year. This results in a total consumption of 130 kWh/year. Pumps are now available with variable flow rates which enables them to respond more appropriately to demand. (Advanced A rated pumps can be up to 60% more efficient than standard pumps.)
1) Any ideas what the run time for the pump will be in a Passivhaus? (how will the reduced heating season affect pump use?)
2) In domestic heating systems (combi and shstem) how widely spread is the boiler manufacturers use of these advanced pumps?
3) In light of the likely reduced run time of the pump (in a Passivhaus) is the capital investment in the advanced pump (and it's control systems) worthwhile?
p.s. questions arise from flicking through http://www.nhbcfoundation.org/Researchpublications/Energyefficientfixedappliances/tabid/518/Default.aspx