hive energy saving report - wordpress.com · the results show that a 26-29% saving in annual energy...

Hive Energy Saving Report

May 2014

001651 Hive_Modelling of Energy Savings Guide_v4.indd 1 29/05/2014 11:04

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Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1 . Introduction and Context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 . Method and Modelling Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 .1 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 .2 Building type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 .3 Location/weather data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 .4 Building fabric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 .5 Internal gains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2 .6 System efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2 .7 Heating profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 . Analysis and Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 .1 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 .2 Annual heating energy consumption and potential savings . . . . . . . . . . . . . . . . . 10

3 .3 Putting the results in context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 . Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5 . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17


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Executive Summary• An independent survey by Buro Happold, commissioned by

British Gas, identified potential savings in energy consumption in households who install Hive Active Heating™ .

• The survey used dynamic thermal modelling of four representative home types across the UK, taking into consideration factors including weather data, building fabric and boiler efficiency .

• The key finding of the study is that annual energy consumption can be dramatically reduced by changing the heating schedules within the home .

• The study results show that a saving of 26% to 29% in annual energy consumption could be achieved by using the Hive default profile compared with an On All Day schedule .

• There is evidence of potential energy savings across all home types and lifestyles by lowering temperature settings and controlling schedules to avoid heating empty homes .


Introduction and ContextThere has been significant global research in recent years which has highlighted the need for simpler, more intuitive heating controls that enable people to reduce their energy consumption . In UK homes, heating accounts for two-thirds of domestic energy consumption (DECC, 2013), so reducing this can have a significant impact on household bills .

British Gas, as the UK’s largest provider of energy, is committed to developing and investing in ways for customers to save both energy and money . One of the easiest and most effective of these is putting control of heating and hot water in peoples’ own hands, literally . In 2012, the company introduced Remote Heating Control, a precursor to the Hive Active Heating™ innovation launched in September 2013 . Hive allows people to control their heating and hot water from their phones, tablets or laptops, wherever they are . This means never needing to heat an empty home again or having to come home to a cold one . With sales of around 100,000 heating systems a year and 50,000 service engineer visits a day, British Gas has both the expertise and the experience to understand what is right for British homes and boilers . To better understand the implications of Hive Active Heating™ on energy usage and potential energy savings, an independent survey was commissioned by British Gas in association with world leading engineers Buro Happold, examining how different heating schedules impact energy consumption in typical homes across the UK .

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There are two main ways to reduce heat energy consumption:

1. Turn the temperature down 2. Reduce the number of

heating hours

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Buro Happold is an independent engineering design practice, which focuses on the built environment . In the field of energy it specialises in projects which reduce carbon: the introduction of new energy sources, the design of efficient building and community systems and effecting behavioural change in the area of demand management . The organisation has delivered energy projects in many countries with clients that span national government, regional and city governance, estate operators, communities, event organisers, housing associations and individual building owners and occupants .

The results of the study have been used to estimate potential energy savings made by using Hive Active Heating™ – remote heating controls which enable you to only heat your home when you need to . To estimate these savings Buro Happold used dynamic thermal modelling of four housing types, and applied five heating profiles, including the Hive Active Heating™ control defaults .

Survey Highlights:

Energy consumption can be reduced by changing your heating schedule temperatures when you are in your home and when you are out or asleep .

Using the Hive Active Heating™ Default setting instead of having the heating on throughout the day could reduce annual energy consumption by up to 29% .

The small print: Any savings quoted in this report are potential savings and dependent on a number of variable factors, such as: your home’s level of insulation, external weather conditions and the efficiency of your heating system .

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Method and Modelling Assumptions

MethodThe study used dynamic thermal modelling of four UK home types located across the UK . Five different heating schedules, provided by British Gas, have been modelled on each home type; aiming to estimate their impact on annual energy consumption .

The modelling was performed using IES (VE 2013) software, which is commonly used in the building industry to understand the environmental performance and efficiency of buildings .

To understand the energy consumption of these types of homes a range of assumptions have been made . To qualify these assumptions a range of sources have been used, including Buildings Regulations and the Chartered Institute of Building Service Engineers (CIBSE) . Where possible the source for that assumption has been stated .

Building TypeThe four types of homes modelled and corresponding total floor areas were:

A flat (66m2) 19% of UK homes are flats

A mid-terrace house (76m2) 29% of UK homes are terraced

A semi detached house (76m2) 26% of UK homes are semi detached

A large detached house (118m2) 26% of UK homes are detached

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2.1

2.2


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Location / weather dataThe location of these homes has been modelled in four places across the UK; in London, Birmingham, Newcastle and Glasgow, using the CIBSE Test Reference Year (TRY; 2005) weather data . The use of TRY weather data aligns with the industry standard regulatory approach .

Building FabricThe thermal performance of the various building elements is based upon a typical level of performance that would be expected in existing housing stock . Building fabric performance is measured using U-values which measure how effective a material is at insulating, the lower the U-value is, the better the material is as a heat insulator and the less energy lost through it . In this study the U-values used were from the 1991 Building Regulations for England and Wales:

Table 2—1 Elemental U-Values

Element U-value (W/m2.K)

Roofs 0 .25

Exposed walls 0 .45

Exposed floors and ground floors 0 .45

Windows, doors and roof lights 3 .3

2.3

2.4


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While these U-values give estimated performance of housing stock built within a single period of time, they are a reasonable indication of a mid-range of performance across the overall mix of UK housing stock . Some homes will have much worse levels of fabric performance (and hence higher heat demand), while others will be better . This study does not include the impact of this on the potential energy savings .

Ground ambient temperature assumed throughout this study was 13°C based on CIBSE Guide C average ground temperature data at 1m for London . Infiltration has been based on 20m3/m2 .hr@50Pa and has been applied to all zones in the model to simulate the ‘leakiness’ of the home .

Internal Gains Internal gains for all occupied spaces were assumed based on the standard National Calculation Methodology dwelling templates . The National Calculation Methodology was adopted as this is the industry standard for Building Regulations and provides reasonable assumptions for existing dwellings . It should be noted that the internal gains have not been varied for the different scenarios modelled .

System efficiencyBoiler efficiency is an important factor that determines how well heat is generated and distributed by the heating system within the dwelling . For the purposes of this analysis the boiler efficiency was assumed to be 81% which is typical of overall system efficiency for existing boilers .

2.5

2.6


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Heating ProfilesFive heating profiles representing different scenarios were tested on each type of home . The baseline for savings was the ‘On All Day’ profile which assumes that people are trying to maintain a consistent temperature of 21°C in the home and a reduced temperature overnight .

The five heating profiles modelled were: 1. On All Day;

2. Standard Programmable Thermostat Default;

3. Family with Kids;

4. Hive Active Heating™ Default Schedule;

5. Professionals Away from Home .

1. On All Day Weekdays: Heating on at 20°C from 6am-10pm .

Weekends: Heating on at 21°C from 6am-10pm . The temperature is set to 7°C overnight .

2. Standard Programmable Thermostat Default Weekdays: Heating on at 20°C from 6 .30-8 .30am,

then 16°C until 4 .30pm and 21°C from 4 .30pm-10 .30pm . Weekends: Heating on at 20°C from 7-9am, then 18°C until 4pm and 21°C from 4-11pm . The temperature is set to 7°C overnight .

3. Family with kids Weekdays: Heating on at 20°C from 6 .30-8 .30 am

then 10°C until 4pm and 20°C from 4pm-11pm . Weekends: Heating on at 20°C from 7am-11pm . The temperature is set to 7°C overnight . .

4. Hive Active Heating™ Default Schedule Weekdays: Heating on at 20°C from 6 .30-8 .30am,

then 10°C until 4 .30pm and 20°C from 4 .30-10pm . Weekends: Heating on at 20°C from 7-9am then 10°C until 4 .30pm and 20°C from 4 .30-10 .30pm . The temperature is set at 7°C overnight .

5. Professionals away from home Weekdays: Heating on at 20°C from 7-8am

then 10°C until 6pm and 20°C from 6-11pm . Weekends: Heating on at 20°C from 8-11am then 10°C until 4pm and 20°C from 4-11pm . The temperature is set to 7°C overnight .

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Analysis and Results

AnalysisDynamic thermal modelling of four types of UK homes was carried out to assess the annual energy consumption associated with heating . Various iterations of the simulation were completed utilising the five different heating profiles in order to assess the variation in heat energy consumption for each scenario .

From this analysis an estimation has been made of the potential energy savings that could be achieved through use of more efficient heating control schedules compared with the ‘On All Day’ heating schedule scenario .

Annual Heating Energy Consumption and Potential SavingsThe comparison with the ‘On All Day’ profile results in the highest annual heat energy saving followed by the comparison with the Standard Programmable Thermostat Default profile . This is due to the higher temperatures used overnight, the slightly higher daytime temperature and the longer usage compared to other profiles .

The Hive Active Heating™ default profile reduces annual energy consumption across all homes, by reducing the number of hours which a home is heated and only heating to a maximum temperature of 20°C . The results show that a 26-29% saving in annual energy consumption could be achieved by using the Hive default profile rather than the On All Day profile . The results also show the potential to achieve a 12-14% saving compared to the Standard Programmable Thermostat Default profile, due to the reduced temperature between 8 .30am and 4 .30pm .

Tables 3 .1-3 .4 give a snapshot of the annual heating energy results for the different housing typologies and heating profiles in London, Birmingham, Newcastle and Glasgow . Temperature profiles with varying set points are compared to show the percentage reduction in annual heating energy consumption .

In summary the annual energy consumption associated with heating increases in correlation with the size of the home . The apparent exception to this is the flat typology, because, whilst this has a smaller area by comparison to the terrace house it has a larger exposed surface area and a larger volume of air to be heated, resulting in a higher level of energy consumption .

The absolute heating energy consumption increases the further north in the UK the home is located, with the detached house in Glasgow consuming most energy annually (based on the ‘On All Day’ schedule) . However, the scale of potential energy savings remains consistent across each home type .

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3.1

3.2

The results show that a 26-29% saving

in annual energy consumption could be achieved by using the

Hive default profile


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Table 3.1 Energy consumption for different types of homes in London

On All Day

Standard Programmable Thermostat Default

Family with kids

Hive Active Heating™ Default Schedule

Professionals away from home

Heating profile Annual heating load (kWh)

Annual heating load (kWh)



% reduction (from baseline)




% reduction (from a standard programmable thermostat)




5,206 4,644 6,827 10,589

5,409 4,816 7,105 11,027

7,604 6,570 9,911 15,530

6,283 5,511 8,192 12,759

5,991 5,189 7,805 12,201

17% 16% 17% 18%

21% 21% 21% 21%5% 6% 5% 4%

14% 13% 13% 14%

17% 16% 17% 17%

29% 27% 28% 29%

32% 29% 31% 32%

Flat Terrace house Semi-detached house Detached house

London


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Table 3.2 Energy consumption for different types of homes in Birmingham

6,270 5,654 8,268 12,774

6,508 5,851 8,586 13,276

9,051 7,886 11,870 18,535

7,553 6,659 9,880 15,343

7,206 6,310 9,440 14,702

17% 16% 17% 17%

20% 20% 20% 21%5% 5% 4% 4%

14% 12% 13% 13%

17% 15% 16% 17%

28% 26% 28% 28%

31% 28% 30% 31%


On All Day


Family with kids



Heating profile

Birmingham














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Table 3.3 Energy consumption for different types of homes in Newcastle

6,406 5,755 8,477 13,091

6,642 5,952 8,799 13,600

9,291 8,079 12,217 19,062

7,725 6,811 10,142 15,737

7,367 6,426 9,682 15,070

17% 16% 17% 17%

21% 20% 21% 21%5% 6% 5% 4%

14% 13% 13% 14%

17% 15% 16% 17%

29% 26% 28% 29%

31% 29% 31% 31%


On All Day


Family with kids















Newcastle


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Table 3.4 Energy consumption for different types of homes in Glasgow

7,096 6,383 9,361 14,420

7,364 6,603 9,717 14,981

10,243 8,909 13,424 20,897

8,567 7,515 11,194 17,336

8,160 7,130 10,699 16,614

16% 16% 17% 17%

20% 20% 20% 20%5% 5% 4% 4%

14% 12% 13% 14%

17% 15% 16% 17%

28% 26% 28% 28%

31% 28% 30% 31%


On All Day


Family with kids















Glasgow


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Putting the Results in ContextTo put the results in context they have been compared to the current Ofgem typical domestic consumption values, which were updated in January 2014 . These figures suggest a typical consumption of 13,500kWh for a medium energy consumer and 19,000kWh for a high energy consumer and correlate with the modelled consumption of a flat or terraced-house, a semi detached house and a detached property .

The most recent data from the Department of Energy and Climate Change (Munton et al .,2014) suggests that of people who have timers or standard programmable thermostats, 14% use one heating period a day . This results in an average heating duration of 10 hours 24 minutes on a weekday, and 10 hours 51 minutes on the weekend .

Hive by British Gas recommends setting a schedule using the heating controls you have available and not heating your home when it is unoccupied . Similarly, eminent research from Massachusetts Institute of Technology (MIT) concluded that using either a manual thermostat or programmable thermostat effectively would result in higher energy savings than an automated system (Gupta, Intille and Larson, 2009) .

However, there are still a significant number of UK homes that have a boiler but do not have a full set of heating controls . Although homes with a condensing boiler are more likely to have a full set of thermostatic radiator valves, a timer and a room thermostat, 71% of UK homes are missing one or more element of control (BEAMA, 2010) .

3.3

71% of UK homes are missing one or more

aspect of control (BEAMA, 2010).


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Of homes with central heating, approximately 10% do not have a timer to control the system (Energy Follow-Up Survey (EFUS), 2011) and are therefore unable to set a heating schedule . A further 23% of people who have a timer do not use it to control the system (EFUS, 2011) and could potentially benefit from doing so .

Installing heating controls is seen as one of six cost effective energy efficient refurbishments people can make to their homes and 6 .5 million household could benefit from new controls (Department of Communities and Local Government, 2009) . Yet standard programmable thermostats often fail to reduce people’s energy consumption because they are extremely difficult to use . People often struggle to use heating controls due to a lack of clear instructions, confusing symbols and the number of steps to programme them (Combe & Harrison, 2013) .

The Hive team at British Gas considers this in the development process and ensures that products are easy to use, transparent about what you are setting and use clear and plain language . This is done by involving customers throughout .

10% do not have a timer to control

the system

23% of people who have a timer do not use it to

control the system


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Conclusions Energy savings can be achieved by using a heating schedule that uses reduced temperatures during the day and overnight . The default heating schedule for Hive Active Heating™, which is set unless and until a customer chooses to change it, consumes 26-29% less energy than the ‘On All Day’ baseline. Changing the heating schedule to a reduced overnight temperature can result in lower energy consumption, however it may also take the home longer to heat up in the morning .

This analysis uses assumptions representative of existing UK housing in terms of fabric and system efficiency, though it does not consider scenarios with behaviour such as opening windows while the heating is on or overriding the temperature manually . The energy use associated with each of the heating profiles relates to the variety and scale of temperature settings and duration of the heating periods . There is potential for energy savings to be realised across all home types and lifestyles by lowering temperature settings. Intuitive and user friendly controls can help people manage their heating and achieve energy savings through using a heating schedule effectively .

The largest heat energy savings can be made by using a schedule effectively . Hive Active Heating™ makes heating schedules easy to set up and change remotely, from a mobile, tablet and laptop . Changing heating schedules from anywhere and using Hive features such as Geolocation; which sends users prompts when they’re leaving home and the heating is on, means that there’s no need to heat an empty home .

User friendly heating controls with features and functionality that make it easier to set heating schedules through simple, intuitive interfaces are giving people greater control of their heating; now from the palm of their hands . This study shows that heating controls, such as Hive Active Heating™, offering greater flexibility, enhanced usability and improved visibility of heating usage, can help save energy and reduce heating bills .

4.

The default heating schedule for Hive Active Heating™ consumes 26-29% less energy than the

‘On All Day’ baseline


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ReferencesBEAMA (2010) Heating and Hot Water Pathways 2010, Report by the Heating and Hot Water Taskforce, Published on 31st March 2010, Available at: http://www .beama .org .uk/en/utilities/document-summary .cfm/docid/8995F4C3-BA4D-4A99-92EE354A2AA252CF

Combe, N. & Harrison, D. (2013) A review and application of usability guidelines relating to domestic heating controls, Intelligent Buildings International, DOI: 10 .1080/17508975 .2013 .828585

Department of Communities and Local Government (2009) English Housing Survey: Housing Stock Report 2009, London: The Stationery Office .

DECC (2013) Energy Consumption in the UK (2013) Chapter 3: Domestic energy consumption in the UK between 1970 and 2012, Department of Energy and Climate Change, available at https://www .gov .uk/government/uploads/system/uploads/attachment_data/file/65954/chapter_3_domestic_factsheet .pdf

Energy Follow Up Survey (EFUS; 2011) Report 4: Main heating systems . Prepared by the Building Research Establishment (BRE) on behalf of the Department of Energy and Climate Change . Department of Energy & Climate Change: London

Munton, A.G., Wright, A.J., Mallaburn, P.S, & Boait, P.J. (2014) How heating controls affect domestic energy demand: A Rapid Evidence Assessment . A report to the Department of Energy and Climate Change . DECC, London .

Gupta, M., Intille, S. S., and Larson, K. (2009) Adding GPS-Control to Traditional Thermostats: An Exploration of Potential Energy Savings and Design Challenges, Pervasive Computing, Lecture Notes in Computer Science, 5538, pp . 95-114

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hive energy saving report - wordpress.com · the results show that a 26-29% saving in annual energy...

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