Turning the dial on home heating behaviours: Are smart heating controls effective in changing home energy use?
07 August 2018
Space and water heating are the two largest sources of energy use in Irish homes. Together they can account for nearly 80 per cent of total energy use in a ‘typical’ home.
As a result, they offer the greatest opportunities for people to save energy in their home and an opportunity to reduce emissions from the residential sector. But, for a lot of Irish homeowners, changing their home heating behaviours is less than straightforward.
Heating controls in Ireland: How easy are they to use?
According to figures from the National Administrative System (NAS) for Building Energy Ratings (BER), the majority of Irish homes have either no heating timer, no thermostat, a simple timer/thermostat, or both. These ‘simple’ controls are usually anything far from simple for people to use.
A 2013 study by the UK’s Department for Business, Energy, and Industrial Strategy (previously Department of Energy & Climate Change) invited people to come into a lab and complete tasks using a range of heating controls such as setting a heating schedule.
The study concluded that “the majority of tasks undertaken with the heating controls resulted in a failure to complete the task”. In fact, none of the controls reviewed in the study met the System Usability Scale (SUS) which is a standard benchmark of how easy it is for people to use a given system.
The study remarked that people struggled to use their heating controls effectively because of complex setup schedules, a lack of error prevention that allowed users to enter invalid settings into the system, a lack of feedback showing that the change they requested was actually made, and a collection of unclear labels, menu paths, and icons.
A sizeable number of Irish homes have more advanced controls in the form of programmer and room level controls while a smaller number of homes have electric storage heaters or time and temperature zone controls.
While these controls offer more flexibility, and savings potential, by allowing people to determine which rooms are heated and for how long, these savings will only be realised if people are setting efficient heating schedules and temperatures.
If people struggle with basic level controls, realising the savings potential of more advanced heating controls may be more difficult than typical assumption-based engineering models suggest.
So, what can we do about it?
The first solution that probably springs to mind of every policymaker is education. The thinking goes, if we teach people how to use their heating controls, they will learn the correct settings that work for them and save more energy.
Indeed, another study carried out by the UK’s Department for Business, Energy and Industrial Strategy, investigated the effectiveness of encouraging boiler engineers to educate people about their heating controls. Boiler engineers were randomly assigned to one of three groups (see image below right):
1.) Control: Engineers performed gas safety checks as they always had with no change to their process.
2.) Advice: Engineers performed the gas safety checks but were also given training on how to give people advice on their heating controls and were asked to do so in every home they visited.
3.) Leaflet: Engineers performed the gas safety checks but also left a leaflet that explained to people how they could use their heating controls to save energy.
(By randomly assigning boiler engineers to different groups as shown in the image, the only difference between the groups should be whether they received no advice on their heating controls, advice, or an information leaflet.)
This allows researchers to measure the impact of the advice on people’s energy use and removes systematic biases that may skew the results. The energy use of customers receiving gas safety checks in all three of the groups was then monitored over the heating season, from October to May. Unfortunately, the study found that there was no significant change in people’s energy usage as a result of either receiving in-person advice or an advice leaflet.
This evidence suggests that giving people advice on how to use their heating controls might not be the most effective approach, but what if we could encourage people to experiment with their heating controls until they found their goldilocks setting?
A study by the energy savings trust in Scotland tried such an approach. Households were encouraged to carry out a number of different ‘experiments’ to try and achieve different goals with their heating controls, helping them to learn how they worked.
A number of homes in Scotland either received a low-cost intervention consisting of newsletter and SMS reminders or a high-cost intervention consisting of newsletters, texts, home visits, smart heating controls, and regular feedback calls.
The study results suggested that 74 per cent of participants reported having changed at least one heating-related behaviour during the pilot. However, the study was small, relied on self-reported behaviour change, and did not include a random sample, which makes it difficult to determine whether the intervention would actually help people use their heating controls more efficiently.
Can smart heating controls help realise savings?
Given that existing heating controls are hard to use and difficult/expensive to teach people about, can smart heating controls help people set more efficient heating schedules and temperatures? Early evidence suggests that the answer might just be ‘yes’.
While there have been only a small number of large-scale experimental studies investigating the savings achieved by the installation of smart heating controls, early evidence does seem to suggest that they can help people use their heating more efficiently and save while doing so.
A quasi-experimental study conducted in the United States evaluated savings from Honeywell’s smart thermostats and found that in total, TCC thermostats would save about seven per cent of energy use for heating and cooling.
A smaller study (125 homes) also evaluated the impact of Honeywell’s smart thermostat coupled with home energy reports (reports that compare a person’s energy use with that of their neighbours and provides actionable tips to save energy) and found suggestive savings of 2.5 per cent. However, these savings were not statistically significant, meaning the finding is not conclusive.
Four studies were also evaluated by the Behavioural Insights Team on behalf of NEST to investigate the savings associated with the installation of the NEST learning thermostat in people’s homes.
While there were varying degrees of certainty across the four studies, the results suggest that the NEST thermostat helps people save energy (see image below), while those customers who installed an additional energy saving algorithm on their NEST made additional energy savings.
The results suggest that people who installed a NEST achieved estimated savings of 4.5 per cent to five per cent of annual household gas use compared with households with programmable timers, room thermostats and TRVs.
Potential in Ireland
It is likely that smart heating controls help people save energy, but how much energy could they help to save in Ireland? The closest estimate likely comes from the Behavioural Insights Team’s evaluation of the NEST thermostat, as the studies utilised robust methodology, were independently validated, and conducted in a climate similar to Ireland’s.
This would suggest savings in the region of 4.5 per cent – five per cent of annual household gas usage. However, these savings were compared to a modern suite of heating controls, for example, those which include TRVs. As the majority of houses in Ireland have lower standards of control, the potential savings may be higher.
The need to test and learn
While there may be potential for moderate savings from the installation of smart heating controls in Ireland, there are a number of factors suggesting that there is an urgent need to validate this with a strong impact evaluation, preferably in the form of a randomised control trial.
First, there are a large number of different smart heating controls available on the Irish market (See main image). A quick online search shows that most of the major utilities in Ireland are now offering smart heating controls as an incentive for customers to switch.
Some of these are likely receiving energy credits per unit installed and so it is important to validate savings. There are also large differences in functionality across smart heating control products and it is likely that different products produce different savings.
Second, and perhaps most importantly, previous studies have shown that there is a large difference between savings estimates produced by assumption-based engineering models and real-world behaviour trials.
For example, SAP-based modelled savings estimates suggest that external wall insulation could save £160 (about €180) while real world experimental data suggests savings are more likely to be close to £72 (about €80).
Large differences between modelled and real world savings
There are likely large differences between modelled and real world savings for heating controls as well. This could be due to, for example, a difference in the amount of hours a day that models assume people use their heating system, and how many hours people really use them.
Smart heating controls offer Ireland an opportunity to save energy in the residential sector while giving people more control over their heating systems and bills. We should robustly identify the scale of that opportunity so we can move forward with confidence.
SEAI offers supports across a number of programmes to encourage homeowners to install smart heating controls. For more information, see here: https://www.seai.ie/
If you, or any one you know, is interested in testing the impact of Smart Heating Controls in Ireland, please get in touch with us at firstname.lastname@example.org
Author: Karl Purcell, SEAIhttp://www.engineersjournal.ie/2018/08/07/turning-dial-home-heating-behaviours-smart-heating-controls-effective-changing-home-energy-use/http://www.engineersjournal.ie/wp-content/uploads/2018/08/a-ae-1024x439.pnghttp://www.engineersjournal.ie/wp-content/uploads/2018/08/a-ae-300x300.pngElecenergy,heat,SEAI