E x a m i n i n g C o s t – E f f e c t i v e n e s s o f P V / T M V H R S y s t e m s
631
gas combi-boiler and MVHR system whose SFP is high, e.g. 1.2 w/l/s (Option 11), is
marginally different from a house with no MVHR (Option 1).
Amongst the alternatives given, Option 4 (i.e. the combination of a combi-boiler + low
SFP & High efficient NUAIRE MRBOX95-WH1 MVHR + PV e + PV
t) could be
considered the most desirable alterative that led to the lowest energy use, cost and CO
2
emission (Figs. 22
&
23)
Figure 22: Delivered and primary energy profiles of 19 alternatives selected
Figure 23: Graph depicting the annual cost of energy (£) for the studied options as per SAP
assessment (2009)
Moreover, it is worthy of noting that the choice of an MVHR system needs to be made in
consideration of the ducting type. According to the assessment, flexible ducts tend to
increase energy use as opposed to rigid ones. An investment of £945.36 for installation
of the MVHR system (Option 4) and £13,656 for solar PV tiles will turn the energy bills
from the annual operating cost of £448 to the additional profit of £64.
-6000
-4000
-2000
0
2000
4000
6000
8000
10000
12000
opt
1
opt
2
opt
3
opt
4
opt
5
opt
6
opt
7
opt
8
opt
9
opt
10
opt
11
opt
12
opt
13
opt
14
opt
15
opt
16
opt
17
opt
18
opt
19
Delivered energy
Primary energy
-100
0
100
200
300
400
500
600
Annual Cost of energy (£)
