Building performance evaluation
Case study report for a student accommodation
In Oxford, UK
Meghana Roy
1. Summary overview of case study
For a Student accommodation in Oxford, UK, a building performance evaluation was conducted to understand and analyze the prototype; to identify the issues and faults in its performance and suggest recommendations to improve the same.
The property located in a residential area, is a 3 storey high and has various blocks with flats of 6 occupants each. The buildings were constructed from 2002, with each flat’s treated floor area accounting to 134 square meters.
Post researching the climate and details of the dwelling, a suitable methodology was chosen to study the building.
An energy assessment was conducted to analyze the fuel bills data to determine electricity, space heating and hot water consumption of the building. Anomalies in predicted and actual data suggested improvements to be implemented.
Further, Energy surveys Including boiler efficiency, energy distribution systems, appliance and lighting audits revealed trends in abnormalities in lighting systems and appliances and piping system.
As part of environmental monitoring, temperature, lux levels and thermal images data was collected, and suggested fluctuations.
Occupant feedback through surveys and interviews revealed user behavior towards systems, services and their satisfaction.
Finally, all the inputs were cross related to propose recommendations for improving the performance of the building. These suggestions were made ranging from low cost to high cost.
Introduction
3.1 Overview of Case study
Sinnet Court, a student accommodation in Southfield road, oxford is selected as the case study building. It consists of 7 three-storied accommodation blocks facing central open courtyards.
Fig1. Shows the map of oxford with major roads, sourced from google styling wizard.
3.1.1 Location
The halls of residence is mainly for the students of Oxford Brookes University and is situated 2km from university and 2.5km from oxford city centre as shown in fig 2.
Fig 2, sourced from google maps styling wizard, points out the location of Sinnet court
Located in a residential area the development is surrounded by houses, Bartlemas conservation area and Oriel college grounds, Sinnet court was completed in 2004 with around 200 units.
Fig 3 is an Aerial image of the property depicting its overall layout and immediate surroundings.
3.1.2 History
Before 1990s: A portion of land was a part of Bartlemas conservation site to the south east. Being a historical landmark, the Oxford city council’s, planning control and conservation did not allow for the student accommodation for a long time.
Fig 3 is historical map of the land from 1956. Fig 4 shows Bartlemas conservation boundary
1900 to 2000: By this time the Southfield road had been formed and residential settlements have increased exponentially. Multiple proposals were made to the council for the construction of Student accommodation. These were rejected on the basis of disturbance to neighborhood, Part of property belongs to conservation site, Privacy and ownership of management who runs the accommodation.
Fig 5 shows proposal layout for accommodation by Kemp and kemp
Post 2000s: After completing all documentation and approvals, the actual construction started in 2002. Student tenancy started around 2006-2007. Multiple conditions had to be full-filled for the approval which had been implemented such as to construction should maintain the character if the neighborhood, restricted number of occupants, certain percentage of landscape to be retained, noise and privacy issues considered in design, etc.
3.1.3 Details of Dwelling
The seven blocks of Sinnet court with flat numbers are:
Flats 1 to 6 : Saxon
Flats 7 to 9 : Bodleian
Flats 10 to 15 : Carfax
Flats 16 to 21 : Radcliffe
Flat 22 : Apollo
Flats 24 to 29 : Spire
Flats 30 to 35 : Sheldonian
Flats 36 to 39 : Magdalen
Flat 15 on second floor of Carfax block is selected as the case study flat for this report. Common areas and bedrooms are studied and analyzed for the same.
and 10
The images of the building depicts the whole character of the accommodation to be humbly fitting in with respect to material choices, height of blocks, and landscape. The site consists of ample bicycle parking space, laundry room in Apollo block, waste disposal area, Car parking, Office and maintenance rooms in the property.
The energy performance of each block varied between C and D rating. Carfax block has a South-east facing entrance looking into the courtyard.
Figs 6,7,8,9
are photographs of Sinnet court outside Carfax block.
Figs 11 shows the floor plan of flat 15.
Flat 15
The flat consists of 6 En suite rooms with a common Living and kitchen Area. Rooms A, B, C are south facing with courtyard views while rooms D, E, F and common areas are north facing located towards rear part of the building.
The area of the flat is 134 m2 and each room is around 13 m2.
Figs 12,13,14,15, 16 and 17 are interior photographs of Flat 15.
Fig 18 summarizes the features of the building Fig 19 shows the EPC rating of the building. Information sourced from energycertificate.service.gov.uk.
3.2 Climate
3.2.1 Temperature
Fig 19 shows the temperature chart of Oxford. Sourced from meteoblue.com
The lowest mean temperature recorded in Oxford is 2C and the Highest mean temperature recorded is 22C over the past decade.
3.2.2 Rainfall And Humidity
Fig, 20 shows the rainfall and humidity levels of Oxford. Sourced from meteoblue.com
As observed from the chart, the highest rainfall was 15mm this year (January 2023 to January 2024 data). Evidently humidity is directly proportional to precipitation and the same is observed in fig. 20.
3.2.3 Sunpath And Wind direction
Fig, 21 shows the sun path diagram for Sinnet court. Fig, 22 shows the wind rose for Sinnet. The buildings that have openings on North east to south west receive the maximum amount of sunlight during the day.
The prevailing wind direction is South west as shown in wind rose in fig, 22
4. Objective and Methodology
Buildings do not perform as intended. They use 6-8 times more energy than predicted. Building performance evaluation methods helps identify the causes of this performance gap to rectify these problems for better functioning buildings.
BPE involves systematic collection and evaluation of information about the performance of a building in use.
Uses of BPE study for Sinnet Court
Identify problem areas in flat which can be Further applied for the whole block and property.
Understand accommodation building type to create feedback loops for designers, construction industry for future buildings
Minimise maintenance costs
Improve occupant satisfaction
POE can help occupants choose their accommodation with more insights about energy and bills
BPE helps owners know where the pitfalls are, if refurbishment is required, or in establishing new maintenance policies.
The objective of this BPE study is to find,
How is the building working?
Through extensive BPE study of this building, considering various parameters, the functioning of the flat shall be assessed.
Is this what was intended?
The findings of these studies will suggest if the building is performing as modelled and constructed or if there are any performance gaps that have occurred.
How can it be improved?
The results will clearly indicate where the fault lies and recommendations on how to solve them shall be suggested. This will help conserve energy and reduce carbon footprint if implemented.
What can we learn from it?
This BPE study can be applied to rest of the blocks at a local level or to every student accommodation at a larger scale to improve the whole prototype. The findings can be implemented in future designs as well.
Fig 23 depicts BPE methodology flow chart
5. Pre Survey Calculations
Based on the CIBSE TM22 framework, a preliminary analysis was conducted and pre survey calculations done for understanding energy use.
5.2 Heat loss calculations
5.2.1 Infiltration heat loss
Due to leakages in buildings, there will be air shifts. This infiltration loss is calculated using the formula
Q infiltration = (Air changes per hour * 0.36*HDDyr*volume) * 24/1000
Assuming the air changes per hour for the room as 5m3/m2/h, and Heating degree days for this year as 2011 (from BizEE).
The infiltration heat loss is 2764 KWh/year.
Manual calculation is attached in Appendix 1.
5.2.1 Fabric heat loss
Building fabric consists of walls, roof, floor, doors and windows. To calculate the conduction heat loss through these elements the formula used is
Q fabric heat loss = (U-value * area * HDDyr) *24/1000.
The U values of building elements have been assumed with respect to the age and construction year of the property (post 2002). Heating degree days for the year sourced from BizEE is 2011.The fabric heat loss calculated is 1260 KWh/year.
From Fig, clearly the walls are worst performing with 42% heat loss, followed by door (20%) and window (15%).
Roofs heat loss is minimal (10%) compared to the rest of the elements.
If areas are taken into consideration, together door and window is only 4.6 m2, but they contribute to a quarter portion of heat loss. If these two elements are addressed, the conduction heat losses can be minimized.
Fig 24 shows the percentage of heat loss through each fabric element
5.3 Energy assessment
In Sinnet court gas boilers are used for hot water only. For space heating, Electric radiators are installed in each room and in common areas.
Fig 25 and 26 shows the location of radiators and DB in plan.
The electricity network operator for Sinnet court is Scottish and Southern electricity network. Each flat has a service room with Distribution board that can be operated for power supply to all end uses.
Since the monthly fuel bills were not available for Sinnet court, Proxy data of another student accommodation, Clive Booth student village, was considered. The idea is to depict and understand the analysis through charts irrespective of data. The data corresponds to 2018-2019 electricity and gas bills. (Pre-Covid data considered for accuracy).
5.3.1
Degree days analysis
To determine the energy consumption of a building with respect to outside temperature variation, degree days is used as a measure. Since the case study is located in UK, we consider heating degree days to measure the severity and duration of cold weather. Base temperature to calculate degree days in UK is 15.5C.
For this case study the heating degree days of each month through 2018-2019 has be gathered from degreedays.net (BizEE).
For Heating degree days analysis, only gas consumption is considered as it is used for hot water and space heating and it shows the correlation between inside and outside temperature. Electricity usage is independent of outside temperatures, hence degree days analysis is not required for the same.
Electricity distribution board for whole flat
Electric radiators
Gas (KWh/year)
Monthly space heating and gas compared with degree days
GAS DEGREE DAYS
Chart 1 shows monthly gas consumption with monthly degree days
As expected, during cold months the gas consumption is maximum (10,22,951 Kwh/year) with an exception of January slightly decreasing due to holiday season and less occupants in the building.
Usually July and August months’ gas consumption is considered roughly as the ‘Base load’ which represents the hot water as space heating is off this time of the year.
Relation between gas consumption and degree days
Gas (KWh/year)
y = 2269.7x + 337228 R² = 0.8402
Heating degree days
Chart 2 shows correlation between monthly gas consumption with heating degree days.
Linear regression analysis on space heating data and degree days in chart determines how responsive the heating system is to outside temperatures.
R2 is the correlation coefficient ranging from 0 to 1 produced by linear regression that tells how well the space heating system is performing. With 0.84 R2 value, the system is
performing very well. If controls are coordinated even better, a higher value can be achieved.
The trend line equation (y=Mx+C) is y = 2269.7x + 337228, where the intercept is 3,37,228 KWh which is the hot water consumption.
The scatter plot shows a strong correlation when degree days are below 200. Divergence increases after 200 suggesting too little or too much usage of radiators with increasing cold weather outside.
Control Chart
ActualPredicted consumption (KWh)
JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN
Months
Chart 3 shows the difference between actual & predicted energy consumption derived from linear regression equation (kwh) with months.
Control chart highlights how the building performed each month. Clearly, from chart 3, the building was not performing as expected in October – November and again in march. The building was performing very well in December- February months suggesting a possible energy conservation.
The Cumulative sum chart depicts the months energy was saved and months energy consumption peaked. This chart helps us predict the reasons why certain savings occurred. For example, during January vacation, few tenants were occupying the student accommodation suggesting less space heating hence more energy savings. Gas consumption peaked in December and march months followed by one last cold wave of the year in May.
The degree days chart data is attached in Appendix 2
CUSUM
CUSUM value (KWh)
Chart 4 depicts the gas CUSUM in each month.
5.3.2 Electricity
Electricity consumption proxy data for Clive booth accommodation indicates a significant increase in October and November. This can be due to early sun sets and need for artificial light for a longer period. The energy consumption decrease in December and January indicates holiday periods and fewer occupied spaces.
A slight rise can be observed again from February as students come back for their terms and decrease in electricity during June to September indicates longer natural light hours.
Electricity used each month
Electricity consumed (KWh)
Chart 5 shows Electricity consumption of clive booth each month for 2018-2019
6. Energy Audits and Surveys
6.1 Boiler and Efficiency
In Sinnet court, each flat has a service room that houses a boiler which supplies hot water to all bathrooms. The boiler was installed in 2005-2006 and is around the same age as the building. The energy rating of the boiler is C which is around 82% - 86% efficient.
The Boiler’s annual electricity consumption is 2731 Kwh/year, adding heat loses due to efficiency percentage the standing heat loss is around 587 KWh/year, so the total energy consumed is 3318 KWh/year
Usually the service room is locked by the maintenance team. So, the controls are set and cannot be changed by occupants. Also, the off-peak and on-peak switches (fig 29) are on. Based on CIBSE AM5 (1991), table 10.4, an estimated 3000 hours is being operated.
Fig 27 shows the boiler in service room.
Fig 28 is the label on boiler with specifications and instructions
Fig 29 shows the off-peak and on-peak switch controls in service room for boiler
Fig 30 shows Megaflo Energy performance rating sticker sourced from their website for this boiler.
Product code
Dimensions 1486 x 579 mm
Weight 40 Kgs (empty) ; 250 Kgs (full)
Capacity 210 L
Element rating 3x3 @240V kW ErP rating C Internal insulation thickness
Standing heat loss 587 KWh/year
Annual electricity consumption 3318 KWh/year
Thermostat temperature set point 60C
Table 1 summarizes boiler specifications
6.2 Energy distribution systems
Hot water from boiler is distributed to each bathroom through piping system. These pipes have a 50mm insulation wrapped around them with aluminum foil outside to Minimise energy losses.
Fig 31 shows the layout of hot water distribution from boiler to shower and sink in each toilet. The hot water supply to kitchen comes directly from a boiler on ground floor.
Apart from the service room, there are service ducts adjacent to each toilet wall that can be operated from corridor (as shown in fig 32) These ducts have waste water pipes and exhaust fan pipes apart from cold and hot water supply pipes.
The location of boiler was efficient as minimum piping is required for distribution.
Although the design and planning of water services is good, the implementation does have some pitfalls. Fig 33 shows that pipe insulation is missing in areas not visible outside. Insulation is broken in multiple areas as seen in fig34, where rust can be observed near pipe joints.
Boiler in service room
Pipeline location
Supplying hot water to shower
Pipe branches out through service duct to connect sink in bathroom
Fig 31 shows the pipe distribution layout of hot water from boiler.
Fig 32 shows access to bathroom service duct from corridor
Insulation around valve controls in pipe not finished properly. Also rusting near joints observed.
Insulation discontinued in service ducts, leading to energy losses through pipes.
Fig 33 and 34 shows the pipe distribution in service ducts
Ventilation extract fans are installed on top of entrance door for each bedroom as shown in fig 36. These join a bigger duct system that is concealed in the false-ceiling of corridor. Thismain duct continues to the service room (fig 35) and further thrown out of the building. Toilet exhaust fans (fig 37) are attached to adjacent air ducts that remove stale air from the space.
These systems need regular maintenance and servicing for proper functioning which is lacking in this building as these extract fans are not very effective.
Fig 35 shows mechanical ventilation ducting system in the ceiling.
Fig 36 shows Extract fan above door in bedroom
Fig 37 shows the extract fan in the bathroom
6.3 Controls and operation
It is vital that the systems installed are easy to control and the user is aware how and when to control them. By doing so a lot of energy can be conserved.
One of the conclusions of Probe papers is to install simple controls as less is more.
6.3.1 Heating
For space heating, Electric radiators are used in Sinnet court. There a total of 8 heaters in each flat; two is common area and one heater per room. All radiators are controlled independently. Since there is no common thermostat, the set point keeps varying as occupants change them according to their comfort levels and out side temperatures.
The location of heater in each room can be seen in main plan (fig 11 ). Only one heater in common area (fig 38 ) is placed below window which is an ideal location as the cold air coming in can be heated if placed this way. Rest of the heaters are placed next to door. The reason for this might be to decrease the electric wiring. But warm air tends to escape when door is opened.
Fig 38 and 39 shows Radiator and its control in common kitchen area
6.3.2 Hot water
The hot water temperature cannot be controlled directly as service room is not accessible to tenants. However, the intensity can be adjusted in the sanitary tap fittings.
Shower fixture, wash basin in bathroom and Kitchen sink are three sources of hot water in the flat.
Fig 4o shows two way tap for hot and cold water in kitchen
Fig 41 shows mixer tap in bathroom washbasin
Fig 42 shows shower panel control system
The washbasin has a mixer tap which is more convenient than the separate 2 way tap in the kitchen. There is also a considerable lag in hot water once the tap is switched on.
All these fixtures need regular maintenance and are sometimes leaky.
6.2 Appliance Audit
Table 2 shows Appliance Audit for the Common Area and Room 15 C.
To understand the amount of electricity each appliance in the flat uses, an Audit with Number of hours it is used, and energy consumed in a year was determined. Some appliances like refrigerators were on continuously and use the most electricity. Since laundry room is on another block, each flat does not have a washing machine or tumble drier.
While each occupant’s use of each appliance varies, an average trend can be observed. Clearly, since kitchen has the most number of appliances and lights, it caters to majority of the electricity consumed.
6.2 Lighting Audit
All light fixures are covered withtransulucent hood whichhave changedcolour over time andhave decresedlight emission from luminaire considerably.
Table 3 depicts lighting Audit for the Common Area and Room 15 C.
The lighting fixtures in Sinnet court use CFL luminaires. There yellow lights in rooms and neutral white lights in common areas. The fixtures are concealed with a translucent fibre plastic that restrict the transmission of light from the bulb.
Fig 43 and 44 shows main CFL ceiling fixture with and without hood.
Fig 45 shows the wall mounted light over study table in room 15C.
Since it is hard to predict the exact number of hours lights are on, a rough estimate was considered. Again, kitchen area is the highest consumer as 6 ceiling lights are fixed and they are on at least 5 hours a day.
7. Environmental Monitoring
7.1 i – Button location and monitoring
Fig 46 shows i –button instrument stuck on wall temporarily to monitor temperatures in common room.
COMMON AREA
Fig 47 and 48 points out the location i – button was installed temporarily to monitor temperatures.
Indoor temperatures of the flat were monitored between 12:00 9th November 2023 to 12:00 21st November 2023. Temperature was recorded with a 30 minute interval.
The first i – button was placed in the bedroom at 1.5m height from the ground away from window and radiator and stuck to a wall shown in fig that is not an external wall.
The second i – button was placed in the common area to an interior wall at a height of 1.6m from the floor level. It was located away from any heat sources such as direct sun light, radiators and heat from appliances. Also a fair distance from window and door was considered while installing the device.
ROOM C
7.2 Indoor and outdoor temperatures
Considering four temperature recordings per day, graph is plotted for 13 days to show temperature profile over this period. This gives us an overall outlookof temperature trends outside and inside.
A distinct pattern is observed with outside temperature varying between 4C to 15C throughout this period. Indoor temperatures ranged between 19C and 25C.
Chart 6 records temperature data over 13 days.
Table below shows the lowest, highest and mean temperatures recorded outside, living area and bedroom during the 13 day period.
Table 4 shows indoor and outdoor temperatures.
It can be observed that even though there was a 11 degree fluctuation in outside temperature, temperature inside was quite steady. For instance on 18th November when outside temperature was around 15C, there was no difference in internal temperatures. This might be due a weekend scenario where heaters were left on when no occupants were present.
7.3 Daily profile
While investigating the temperature patterns, it is important to understand hourly profile, so a 24 hour temperature data of 17th November is plotted in graph.
Chart 7 shows temperature data over a 24 hour period.
It is observed that the co-relation between outdoor and indoor temperatures on this day is not an ideal scenario. Usually when outside temperature decreases (becomes colder), Indoor temperature should come on (make indoors warmer). However, the opposite is recorded in this case. Indoor temperature is increasing with outdoor temperature. This clearly shows radiators are not controlled well. Or the occupant is comfortable at a certain temperature and left it the same. It can also be observed that from 5pm, the temperature increased exponentially in common area. This might be due to multiple flat members using the space and also due to cooking.
7.4 Living room temperature analysis
Chart 8 compares daily mean temperatures with CIBSE recommended temperatures
Chart 8 represents daily mean temperature along with maximum and minimum temperature in common living area. The dotted line in graph is the recommended living room temperatures to be maintained according to CIBSE (2006). It is observed that the mean temperature mostly fluctuates between 21C and 23C. This is slightly higher than recommended levels.
7.5 Bed room temperature analysis
Daily mean temperatures in Bedroom
Outdoor temperature (°C)
Minimum temperature
CIBSE recommended temperature
Bedroom-Indoor Temp (°C)
Maximum temperature
Chart 9 compares daily mean temperatures with CIBSE recommended temperatures.
The chart represents daily mean temperature along with maximum and minimum temperature in bedroom 15 C. The dotted line in graph is the recommended bed room temperatures to be maintained according to CIBSE (2006). It is observed that the mean temperature recorded is 22.85C which is almost 4C higher than recommended level.
This could be due to multiple reasons. Since the occupant’s native country temperature is much higher than UK’s cold climate, the occupant might feel comfortable at higher temperatures. This is one of the common feedback in student accommodations since most of the tenants are international students.
Other possible reasons could be not controlling the radiator properly, heat from study light and laptop since the i- button was placed on study table wall.
7.6 Thermal Imaging
To identify heat losses, thermal bridging and air leakages, a thermal imaging camera was used. It was made sure that there were ideal conditions like no rainfall, buffer period after sunset, outside temperatures were cold enough and the rooms were warm enough to see cold bridges to perform thermography study.
7.6.1
Bedroom
Fig 49 and 50 shows cold bridges near window sill in bedroom
Clearly the window in bedroom is performing poorly. Since the same window type is used throughout Sinnet court, we can assume a similar result for rest of the windows.
Fig 51 and 52 shows cold bridging in floor junction.
This corner in the fig 51 shares bathroom wall, external wall and flooring. This suggests the corners aren’t performing as intended.
7.6.2 Common Area
Fig 53 and 54 shows a corner of kitchen area in common room.
From fig 53 there is heat loss from window corners and wall junctions. Even with heater on the adjacent outer wall seems to have some cold bridging.
Fig 55 and 56 shows a maintenance access panel and roof-wall junction. The access panel in ceiling used for maintenance and services does not have proper thermal insulation in corners indicating heat loss along its perimeter. Also the roof – ceiling junction is poorly performing with cold bridges.
Fig 57 and 58 shows a corner of living area in common room.
Again air leakage is observed around the window perimeter. Roof seems to be performing better in this junction while there is evident heat loss between wall junctions. Also the exterior wall seems to be colder than the interior partition walls.
From Thermography test it is observed that
Poor window frame performance
Heat loss in joints and junctions
Lack of insulation in maintenance and service doors.
7.7 Light meter study
Using a light meter, the lux levels were studied in the common room and bedroom in Flat 15. Natural and artificial light levels were recorded for both spaces.
From CIBSE energy audits and surveys table 10.11, which provides standard illuminance levels for interiors and activities, obtained lux values are compared. Light level outside was measured to be 395 X 10x.
Fig 59 depicts light dispersion in room through natural light.
Fig 60 depicts light dispersion in room through Artificial light.
Fig 59 and 60 shows how poor the lighting system is in the bedrooms. With study lamp and main ceiling light on, the lux level recorded on study table was 80 lux. The recommended lux levels for working is around 300.
Artificial light Lx levels in kitchen are better. Since the common area is location on the rear side of the building with north window openings, no direct sunlight is received.
Fig 61 depicts light dispersion in room through natural light.
Fig 62 depicts light dispersion in room through Artificial light.
10. Occupant Feedback
Occupants views about their home is a very important section of BPE, since we design for them. Their comfort, usage, perception and satisfaction is crucial.
For this case study three sets of data analysis: a preliminary survey, BUS questionnaire and an informal interview were conducted for flat 15 tenants of Sinnet court student accommodation.
The full surveys are attached in the Appendix.
10.1 Occupant Overview
During the survey, there were 5 occupants in the flat. Their profile overview is summarized in table
Table 5 summarizes occupant profile.
General questions
For a rating system from 1 to 7 (1 being unsatisfactory and 7 being satisfactory), occupants feedback on general questions asked in BUS survey are summarized in graph 10.2 Occupant 1
questions about the flat Chart 10 shows
Preliminary Housing evaluation survey findings
Lighting
Direct sunlight hours
Curtains/Blinds pattern
5 to 6
3 to 4 times a day while changing for privacy
Artificial light required during day ? Yes
Comments
Main light is dim. Need to switch on study light as well
Laundry practice
Number of loads per week One load
Towel drying place in room On bed
Is window open when clothes are drying in your room? No
Do you iron any of your clothes? No
Comments
Heating system
When is your heater normally on ?
Unhappy with laundry. Faulty tumble dryers.
Once or twice a week for a few hours
Temperature range set on your heater 30
How often do you change temperature ? Never changed even once. When you feel warm what do you do ? Change clothes
Comments
Water
I do not feel cold. Hence I hardly turn on the heater.
Showers taken per week 14
Approximate time taken for each shower 15 to 20 minutes
How easy is control system for hot water ? Very easy
Comments
Indoor air quality
How do you ventilate ?
More water can be conserved if we had a dish washer
Open Windows
Is your window open or close while sleeping ? Closed
Is your window open or close while sleeping ? No
Is your window open or close while sleeping ? No
Is your window open or close while sleeping ? No
Is your window open or close while sleeping ?
Feels stuffy if windows are not opened regularly
Table 6 shows selected summary of certain parameters of preliminary survey.
BUS Questionnaire
Fig 63 shows BUS survey of Occupant 1.
Answers to questions about habits and changes that relate to above responses:
“Room feels stuffy if windows are not open for long durations” .
“Even though there are noise problems, since I’m nocturnal it doesn’t bother me”.
“Artificial light could have been better” .
“As I go to gym often, I have more laundry. The drier takes two cycles usually to dry clothes which is expensive and energy consuming” .
“Since I have more heat in body, I do not feel very cold and hence not use heater regularly”
“Wish there was more fridge storage”
10.3 Occupant 2
Preliminary Housing evaluation survey findings
Lighting
Direct sunlight hours 4 to 5
Curtains/Blinds pattern
Closed most of time for privacy
Artificial light required during day ? Yes
Comments
Laundry practice
Very poor lights.
Dim lights straining my eyes
Number of loads per week 1
Towel drying place in room Chair
Is window open when clothes are drying in your room? Yes
Do you iron any of your clothes? No
Comments
Heating system
When is your heater normally on ?
Unhappy with dryer machines
Evenings and mornings
Temperature range set on your heater 20° C to 24° C
How often do you change temperature ? Once a week
When you feel warm what do you do ? Open Window
Comments
Water
Satisfied with heaters as I get more control.
Showers taken per week 6
Approximate time taken for each shower 30 How easy is control system for hot water ? Easy
Comments
Indoor air quality
Shower is leaky sometimes. Needs maintenance
How do you ventilate ? Open Windows
Is your window open or close while sleeping ?Sometimes open slightly. Is mechanical ventalition system effective ? No
Any visible signs of condensation ? No
Noticed any mould or dew on walls ? No
Comments
Exhaust fans are not effective.
Table 7 shows selected summary of certain parameters of preliminary survey.
Questionnaire
Answers to questions about habits and changes that relate to above responses:
“Temperature is manageable for now and I do use heater every day” .
“Although Sinnet is quite, the walls between rooms are very thin. It is very disturbing sometimes while trying to study or sleep”
“Light systems need changing. Very dim fixtures”
“I do get very good amount of sunlight. But my window position is opposite to common room of another block. So for privacy, I am sometimes forced to close blinds” .
Fig 64 shows BUS survey of Occupant 2.
10.4 Occupant 3
Preliminary Housing evaluation survey findings
Lighting
Direct sunlight hours
2 to 3 hours
Curtains/Blinds pattern Always open
Artificial light required during day ? Yes
Comments
Full privacy as flat is on rear side. Study lamp location faulty. Horrible lighting fixtures.
Laundry practice
Number of loads per week once in 2 weeks
Towel drying place in room chair in front of heater
Is window open when clothes are drying in your room? Yes
Do you iron any of your clothes? No
Comments
Heating system
When is your heater normally on ?
Expensive laundry
All the time
Temperature range set on your heater 22C to 25°C
How often do you change temperature ? Once a week
When you feel warm what do you do ? Change temperature setting
Comments
Water
Showers taken per week
Window always open a little.
5
Approximate time taken for each shower 15 to 20 minutes
How easy is control system for hot water ? easy
Comments
Indoor air quality
How do you ventilate ?
Water filter is necessary.
Wndows, exhaust fans
Is your window open or close while sleeping ?open
Is mechanical ventalition system effective ? yes
Any visible signs of condensation ? no
Noticed any mould or dew on walls ? no
Comments
Table 8shows selected summary of certain parameters of preliminary survey.
Questionnaire
Fig 65 shows BUS survey of Occupant 3.
Answers to questions about habits and changes that relate to above responses:
“Since my room is in the rear corner I do get some east sunlight unlike other north facing flats” .
“Very happy with privacy and less noise than courtyard facing flats”
“I have never closed the blinds. I wish there were more windows in my room”
“A window is always slightly open even when heater is on. I feel it balances the air properly” .
“Horrible lighting” .
“The layout and arrangement of my furniture is also disappointing. I keep shifting furniture which affects my switch board operations” .
10.5 Occupant 4
Preliminary Housing evaluation survey findings
Lighting
Direct sunlight hours none
Curtains/Blinds pattern 3 to 4 times when changing
Artificial light required during day ? Yes
Comments
Laundry practice
Number of loads per week Twice a week
Towel drying place in room On radiator
Is window open when clothes are drying in your room? yes
Do you iron any of your clothes? no
Comments
Blinds are open all day to maximise whatever light is coming in unhappy with number of laundry machines and price
Heating system
When is your heater normally on ? whole night and morning
Temperature range set on your heater 20C
How often do you change temperature ? never
When you feel warm what do you do ? turn off heater, open window
Comments
Water
Showers taken per week 7
Approximate time taken for each shower 10 minutes
How easy is control system for hot water ? easy
Comments
Indoor air quality
How do you ventilate ? open windows
Is your window open or close while sleeping ?closed Is mechanical ventalition system effective ? no
Any visible signs of condensation ? no
Noticed any mould or dew on walls ? yes
Comments
Small black dots in the ceiling of washroom
Table 9shows selected summary of certain parameters of preliminary survey.
Answers to questions about habits and changes that relate to above responses:
“I only close my blinds when I am changing. Otherwise blinds are open throughout the day” .
“Too much noise between rooms that I sleep with ear plugs”
“Very bad lighting. They are straining y eyes”
“Wish the shower area was bigger. Room is a little small”
“There is small mould spots on my bathroom ceiling. I am not bothered by it for now. If it grows I will do something about it” .
Fig 66 shows BUS survey of Occupant 4.
10.6 Occupant 5
Preliminary Housing evaluation survey findings
Lighting
Direct sunlight hours
none
Curtains/Blinds pattern 2 to 3 times a day
Artificial light required during day ? Yes
Comments
Very bad lighting. Installed LED fairy lights and bed lamp
Laundry practice
Number of loads per week Once a week
Towel drying place in room Bathroom Is window open when clothes are drying in your room? No
Do you iron any of your clothes? No
Comments
Heating system
When is your heater normally on ?
5-6 hours a day
Temperature range set on your heater 22C to 25°C
How often do you change temperature ? Everytime heater is on When you feel warm what do you do ? Turn off heater
Comments
Sometimes I open windows when heater is on
Water
Showers taken per week
4
Approximate time taken for each shower 40 to 45 minutes
How easy is control system for hot water ? easy
Comments
Indoor air quality
How do you ventilate ? Open windows
Is your window open or close while sleeping ? closed
Is mechanical ventalition system effective ? No
Any visible signs of condensation ? No
Noticed any mould or dew on walls ? No
Comments
No cross ventilation as doors can't be kept opened
Table 10 shows selected summary of certain parameters of preliminary survey.
BUS Questionnaire
Fig 67 shows BUS survey of Occupant 4.
Answers to questions about habits and changes that relate to above responses:
“There is no sunlight what so ever. No view from window.”
“There is spider problem so I do not like opening windows.”
“Got a study lamp and LED fairy lights to balance lack of light in room” .
“Room feels stuffy most of the time”
“There is not enough storage space for all my things”
“I wish we did not have carpet flooring as it can get quite dusty”
“My room shares a wall with common area which is always noisy”
“I feel like my health has deteriorated after moving to UK” .
Chart 11 shows ratings for given parameters in BUS survey.
From the graph, it is evident that Lighting is very poor in bedrooms followed by lack of acoustic insulation on walls as tenants are complaining about noises.
From all the occupants surveys it is also clear that, tenets are happy with heating and hot water systems, although the way most of them are using radiators is not recommended for energy conservation
Throughout the interviews, flatmates showed interest in understanding how radiators are supposed to be correctly used. When discussed about recommended indoor temperatures by CIBSE, almost all tenants confined that they would not feel comfortable in such low temperatures indoors except one Italian occupant.
11. Cross Relation and Key Findings
With all the information gathered and data analysis, the overall performance of the flat is quite acceptable, while there is a lot of scope for improvement.
Firstly, the positive aspect of the flat is that it already has efficient boiler installed and since the building age is also post 2002, the assumed U-values were also good. The building has a C rated energy certificate as well.
The planning of the flats with services employed into them was very effective and energy saving as a design project.
From pre-survey calculations, to minimise the fabric heat loss further, windows and doors can be improved as theycater to 25% of heat loss and would also cost less than improving other elements of building fabric. When thermal images were analysed it became clear that the loss through doors and windows might be much higher than the assumed fabric heat loss percentage.
From Degree days analysis, we can note that as degree days increase, its correlation with gas was fluctuating indicating too much or too little usage of heaters with increasing cold weather outside. This information can be cross related to i – button analysis where in chart 7 there was a similar trend where indoor temperatures increased even when outdoor temperatures were going up.
Also control chart and CUSUM chart indicated that in few months, the gas consumption is more than predicted levels. This could be due to lack of controlled heaters.
Energy audits and surveys revealed some loopholes from design and implementation of services. Firstly, it was observed that pipes were not insulated throughout. This was observed inside service ducts where hot water pipes were exposed to heat loses. Then while servicing or maintenance, insulation was teared down near junctions where rust formation was observed.
The ducting system for exhaust fans is not efficient enough. This was confirmed during occupant survey when tenants complained about stuffy and suffocating rooms.
From appliance and light audit, Kitchen consumed most amount of energy in the flat. By checking appliance ratings and its electricity consumption, a more efficient appliance can be replaced with a poor one.
One of the biggest issue in Sinnet court is the Lighting system. This problem constantly raised in every study, in lighting audit, light meter readings and occupant surveys. It is crucial to address this elephant in the room. The light fixtures are CFL bulbs using more energy. These can be replaced with LED strips which are 12 times better in light emission, energy consumption and longevity of the fixture.
Occupants not using radiator controls correctly is also a reason for higher energy consumption. Although it was thoughtful to provide the tenant with radiator controls, it is equally important to educate them on how it must be operated. This information can be cross related with i – button temperature analysis with CIBSE bench marks and occupant behaviour with respect to heating controls.
Occupants are unaware of their energy consumption in Sinnet court. This is due to the accommodation prototype where the rent includes the fuel bills. This business model needs to be questioned as occupants tend to subsidise fellow flatmates energy and end up paying the same amount and vice-versa. More than this, if the occupant is not directly paying for bills, he would not have the mind set to save energy.
Water supply through two-way tap caters to significant amount of water loss as cold water is too cold and hot water is too hot. A mixer tap is a better solution to adjust the temperature as required.
Noise is another prominent problem occupant complained about. However very little can be done unless the wall’s acoustic property is improved.
To understand where more energy is being spent, smart meters or sub metering can be installed so that the problem can be identified at root.
From thermal images, cold bridges were identified in joints and junctions, windows, doors, access doors, etc. This might also be the reason why temperatures in bedrooms are higher. With heater located near door, while study table and bed where more time is spent is adjacent to window and external wall, the occupant tends to feel cold even with higher temperatures.
For all these issues, the following section gives out recommendations for improvement.
12. Recommendations
Recommendations
Turn off appliances and heaters consciously when not using
Operate doors and windows consciously to control air flow
Replace filters in extract fans
Set radiator temperature consciously (every 1 rise increases energy consumption by 10%)
Install smart meter
Insulate loft access hatch to Minimise cold bridging
Educate tenants about energy and controls
Attempt to change business model to separate rent from fuel bills to make user accountable for their energy consumption
Install continuous insulation on hot water supply pipes
Maintain and service all ducts, pipes, taps, extract fans, service room, boiler etc.
Replace two way tap with mixer tap.
Electricity savings
Improved air quality and ventilation
Improved mechanical ventilation
Energy conservation
£30
£25 - £30
User control over energy use
Heat loss reduction in roof
£100 - £200
Increase awareness in occupants
Increase awareness in occupants
Minimise heat loss
For better functioning and longevity of systems
Water conservation
£100
Service fee
£40
Medium
Recommendations
Replace CFL light fixtures with LED light fixtures throughout the flat Better light, energy efficient
Improve window frames Avoid air leakages and cold bridges
Replace doors with better U-value doors
Reduce fabric heat loses
Replace poor performing kitchen appliances with efficient ones Energy conservation
High cost Recommendations
Replace windows Improves Air tightness, Uvalue and energy savings
Replace boiler with heat pump Reduces carbon emissions, low energy bills
Acoustic insulation to walls for noise Decreases noise, improves wall
Table 11 shows low cost, medium cost and high cost recommendations
£500
£1000
£500 for each door
£1000
£7000
£10000
£5000
13. CONCLUSION
Using Building performance evaluation, a flat in Sinnet court Student accommodation has been investigated in terms of its energy, systems and services, temperature and occupant feedback.
The performance of the building was analyzed and issues hindering its better operation were identified and addressed. These issues were correlated with other factors affecting them to understand the scale of the problem.
Finally, suitable recommendations were provided based on cost factors.
This study done for Flat 15 can be considered as a prototype and can serve as basis for identifying issues in other flats of Sinnet court. If recommendations are successfully implemented, this project can be added to the feedback loop for other existing and design stage Student accommodations in UK.
14. References
Bizee, 2023. degree days [www document]. url www.degreedays.net
CIBSE, 1991. energy audits and surveys AM5.
Gupta, R. (2023) Pre-Survey Calculations
CIBSE (2002) CIBSE Guide F: Energy Efficiency In Buildings: Draft Report London: Chartered Institute Of Building Services Engineers.
CIBSE (2008) Energy Benchmarks. London: Chartered Institute Of Building Services Engineers.
CIBSE (1991) Energy Audit And Surveys. London: Chartered Institute Of BuildingServices Engineers.
1.
Manual Heat loss calculations
2. Degree days analysis table
3. Electricity data for clive booth
AUGUST 93,690
SEPTEMBER 112,297
OCTOBER 167,139 NOVEMBER 142,551
DECEMBER 133,291
4. I- button temperature table
5. I- button temperature table for living room
6. I- button temperature table for bed room
7. Bus survey
8. Preliminary survey
Thankyou.