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Until recently, most low carbon retrofits have been carried out by experts and enthusiasts on their own houses. However, retrofit needs to move rapidly into the mass market if we are to meet our carbon reduction targets. What if occupants are not experts? Is "usability" dependent on context, user goals, and the user's ability to achieve these with "effectiveness, efficiency and satisfaction" a useful framework for assessing the success of low carbon retrofit? Do the goals of users match those of designers? What evidence is there of good and poor usability in low carbon retrofit? Residents’ primary motivations for involvement were reduced fuel bills and improved comfort, rather than green issues. Initial monitoring has revealed the importance of usability and personal control in achieving these aims for the residents. In this they are likely to be closer to the typical mass-market customer than the early pioneers. Marianne Heasleip from URBED presented initial findings from a set of linked case studies of completed low carbon whole house retrofits in the social housing sector the UK. Her findings point to the importance of matters such as the specification of controls, the quality of handover information, the importance of communication whilst the works are in progress and the need for ongoing customer care. This is likely to have management and cost implications in any mass market retrofit scheme. She suggests that usability should indeed be a significant concern for designers, of both whole houses and individual products, at strategic and tactical levels.
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low carbon housing for non-experts: usability in
whole house retrofit
Marianne HeaslipURBED
Eco-Housing for Non-Eco-Geeks
Most low carbon ‘retrofits’ designed by, and for, experts and enthusiasts
But we need to hit the mass-market to achieve carbon reduction targets....
...the equivalent of a city the size of Cambridge every month ‘til 2050
Encouraging technology uptake..?
Potential pitfalls...Building performance doesn’t match design stage predictions:
• Due to build quality and changes during procurement?
• Due to inaccuracies/ false assumptions in modelling?
• Due to user behaviour?
How can we convince people to opt for the measures if:
• It involves ‘letting the builders in’?
• Their homes become less ‘user-friendly’?
• The cost savings aren’t guaranteed?
Significance of usability?
'e extent to which a product can be used
by speci"ed users to achieve speci"ed goals
with effectiveness, efficiency and satisfaction
in a speci"ed context of use'
(ISO/TR 16982:2002)
Measures were tailored to lifestyle and residents’ tolerance of disruption...
...but also a desire by design team to ‘test’ different measures
Different levels of complication and different fuel sources
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• Different levels of technical confidence and environmental awareness
• Seeing the construction process helped understanding
• Induction process...
Userʼs goals for retrofit
• Reduced bills (6)
• Interest in ‘green issues’ (2)
• Relative had solar panels and they wanted them too (1)
• Peer pressure (neighbours wanted their house ‘done’) (1)
• Doing their ‘civic duty’(1)
• Work needed to be done to the house anyway (2)
• Wanted the house to be more ‘modern’ (1)
• “Just wanted new windows”(!) (1)
(of 7 households)
Userʼs ʻeverydayʼ goalsA E
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• Wide range of comfort temperatures
• Different levels of washing, laundry etc
• Accommodating pets and ‘everyday’ habits
System Controls (effectiveness)
• Only 2 residents have a good grasp of control systems - both self-confessed ‘techies’
• Other residents have struggled with controllers, don’t understand displays, don’t use all features, and are worried by them: “Does the flashing light mean something is wrong?”
• Residents with standard gas boiler and PV panels have the fewest issues so far...
• Biomass+solar thermal systems seem to require the most input (logs).....but residents generally happy
• Exhaust Air Source Heat Pump has caused the most commissioning and control issues so far....
Control/Interface Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating House Comment on Resident Use
1 2 3 4 5
clarity of purpose AResidents don’t use timer, just flick on and off as needed, using thermostat as a limit, but often switching off before this temp is reached. intuitive switching B
Residents don’t use timer, just flick on and off as needed, using thermostat as a limit, but often switching off before this temp is reached.
usefulness of labelling C
ease of use D
indication of system response/feedback
E
degree of fine control F
Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. Cover is fiddly to flip up to make adjustments, screen is not very clear or big. Symbols hard to understand. Small buttons. G
Use manual control and thermostat with thermostat as limit.
Cen
tral
Hea
ting
Con
trol
Control/Interface Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating House Comment on Resident Use
1 2 3 4 5
clarity of purpose A
intuitive switching B
usefulness of labelling CUnderstand some settings, but don’t like not being able to switch ‘off’.
ease of use D
indication of system response/feedback E
Understand some settings, but only use to adjust temp up and down a bit.
degree of fine control FVery good understanding of system, navigates menus to control as needed.
Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. Lots of digital menus and sub-menus to navigate. Labelling very abstract. Constant temperature read-out. Small backlit display. G
Cen
tral
Hea
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Sol
ar C
ontr
ol
Control/Interface Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Houses Comment on Resident Use
1 2 3 4 5
clarity of purpose A
intuitive switching B
usefulness of labelling CDo use when cooking - noise as system feedback.
ease of use D
indication of system response/feedback
E
degree of fine control F
Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. Switching is easy for the boost to the MVHR - but no indiction of whether the system is already on boost - other than noise. G
MV
HR
Boo
st (K
itche
n)
Control/Interface Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating Usability Rating House Comment on Resident Use
1 2 3 4 5
clarity of purpose A
intuitive switching B
usefulness of labelling C
ease of use DVery good understanding of system, including adjusting ‘heatcurves’ etc.
indication of system response/feedback E
degree of fine control F
Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. Digital screen is hard to read in bright light and usually hidden. Symbols hard to understand without handbook. G
Cen
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Hea
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Hea
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ump
Con
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9
Displayenhet MenysystemNär dörren till värmepumpen öppnas visas menysystemets fyra huvudmenyer samt viss grundinformation på displayen.
DisplayPå displayen visas instruktioner, inställningar och driftinformation. Med hjälp av den tydliga displayen och ett lättanvänt menysystem kan du enkelt navigera mellan olika menyer och alternativ för att ställa in den komfort eller få den information du önskar.
StatuslampaStatuslampan indikerar värmepumpens status. Den:
• lyser grönt vid normal funktion.
• lyser gult vid aktiverat reservläge.
• lyser rött vid utlöst larm.
OK-knappOK-knappen används för att:
• bekräfta val av undermeny/alternativ/inställt värde/sida i startguiden.
Bakåt-knappBakåt-knappen används för att:
• backa till föregående meny.
• ångra en inställning som ej bekräftats.
ManöverrattManöverratten kan vridas åt höger eller vänster. Du kan:
• förflytta dig i menyer och mellan alternativ.
• öka eller minska värden.
• byta sida i flersidesvisningar (t.ex. hjälptexter och serviceinfo).
StrömbrytareStrömbrytaren har tre lägen:
• På ( )
• Standby ( )
• Reservläge ( )
B Statuslampa
A Display
C OK-knapp
D Bakåt-knapp
E Manöverratt
F Strömställare
A
F470
B
C
D
E
F
Meny 1 - InomhusklimatInställning och schemaläggning av inomhusklimatet.
Meny 2 - VarmvattenInställning och schemaläggning av varmvattenproduktionen.
Meny 3 - InfoVisning av temperatur- och annan driftinformation samt tillgång till larmloggen.
Meny 4 - VärmepumpInställning av tid, datum, språk, display, driftläge mm.
Meny 5 - Service Avancerade inställningar. Dessa inställningar är ej åtkomliga för användaren. Menyn blir synlig genom att bakåt-knappen trycks in i 7 sekunder.
Startguide
Första gången värmepumpen startas sätts en startguideigång. I startguiden ges instruktioner om vad som behöverutföras vid första uppstart tillsammans med en genomgångav värmepumpens grundläggande inställningar.Startguiden säkerställer att uppstarten görs på rätt sättoch kan därför inte hoppas över. Startguiden kan startasi efterhand i meny 5.7.
Inomhustemperatur – (om rumsgivare finns)Utetemperatur
Varmvatten-temperatur
Extra varmvatten (om aktiverad)
Uppskattad mängd varmvatten
Fuel usage and costs (efficiency)
• Early results based on resident reporting......not robust yet!
• Residents report cost savings - but these vary significantly
• Several residents report significant savings - and appear to be undershooting design targets for energy use and CO2 emissions
• One resident reports small savings - but issues with thermostat setting and MVHR/window opening
• Will only be able to make a proper assessment once one year+ of data available
Comfort (satisfaction)
• Residents report increased thermal comfort:
“I don’t have to go to bed in thermals and a jumper anymore”
• Appears to be correlation between comfort, control and satisfaction - adaptive comfort (?)
• Noise from MVHR an issue
A
B
C
D
E
F
G
0 1 2 3 4 5 6 7
Control Over Heating
No Control More Control
A
B
C
D
E
F
G
0 1 2 3 4 5 6 7
Comfort Overall
Unsatisfactory Satisfactory
Other factors affecting satisfaction
• Stress of construction process
• Quality of finish
• Responsiveness of maintenance
• Quality of aftercare and support
• PV + behaviour change
• ‘Added bonus’ e.g. window cills, master-switch+parental control, reduced clothes washing
• Improved environmental awareness
Initial conclusions and implications• Cost savings of measures/households vary significantly -
- a significant issue if cost is a major motivator?
- implications for the ‘Green Deal’ and fuel poverty?
• Some approaches more ‘fit and forget’ than others - can’t rely solely on ‘techno-fix’
• Feeling of ‘control’ very important - related to satisfaction and usability
• Huge variations in ability to cope with change, level of interest and motivations among residents
• Residents want to be involved throughout the process and need support afterwards - customer care needs to be a priority
• Usability is key!
Evolution in design?
....BUT Even iPhones aren’t always ‘useful’...
Computers have evolved...can retrofit?
“I made up my mind . . . that I would never try to reform man—that’s much too difficult. What I would do was to try to modify the environment in such a way as to get man moving in preferred directions”
R. Buckminster Fuller
