Aecom Report On Life Cycle Costing:
Continuous Flow Up To 7% More
Cost Effective
AECOM, a major global player in the building engineering services consultancy arena, has concluded a report
showing that continuous flow water heating systems have a clear advantage in terms of initial capital costs as well
as life cycle costs over 20 years, when compared with stored hot water systems*.
The study** shows that continuous flow
water heating systems can be up to 7%
more economical than equivalent ‘tradi-
tional’ stored hot water systems.
AECOM was commissioned to carry out
a life cycle study on continuous flow
water heating systems, and to provide a
comparison with conventional storage
systems. Two case studies were provided
that are based on projects using continu-
ous flow water heating systems.
AECOM then determined an equivalent
storage based system for each case study
and compared operational and capital
costs.
For the life cycle comparison, the analysis
period was 20 years, based on the ex-
pected service life. The net present value
(NPV) calculation is based on a discount
rate of 3.5% (The GREEN BOOK - HM Trea-
sury), an inflation rate of 2% for servicing
costs and projected retail fuel costs from
DECC1.
In both case studies the continuous flow
system showed a clear advantage in
terms of initial capital costs, as well as life
cycle costs over 20 years, with the con-
tinuous flow system consistently lower in
energy use than the two storage systems.