Submission by Heatermate to the ESI Review Issues Paper
Submission to the Energy Saving Incentive Scheme Review
Dr Michael Bazylenko, Heatermate Controllers Pty Ltd
Due to ongoing increases in the electricity prices many Australians are realising that in order to manage their Heating/Cooling costs it is quite often wise to heat/cool only rooms which are being used, not the entire house. As the zoning of the central ducted air-conditioning to individual rooms with individual temperature sensing is currently very rear, the individual room heaters and air-conditioning units, both portable and stationary, are very popular. Estimates based on the published data  indicate that there are currently over 10 millions portable electric heaters and several millions portable and window air conditioners owned by the Australian households.
At the same time, it is becoming widely recognised that a precise, digital room temperature control is an important energy saving requirement when heating or cooling individual rooms. Numerous sources point out [e. g. 2], that every degree C of the unnecessary heating or cooling adds around 10% to the related electricity costs. Let us call it "10% per degree" rule. Thanks to the State and Federal Governments efforts in energy saving education, more and more Australians are becoming aware of this rule.
However, having learnt about this "10% per degree "rule, many existing users of heaters and air-conditioners discover with frustration that their heater or air-conditioning unit lacks the accuracy in setting the room temperature with a degree precision to save on energy bills by implementing this rule in practice.
While many of the existing portable heaters or air conditioners do have a mechanical thermostat, it is typically a knob-dial style with an arbitrary scale (e. g. 1-10) which (i) does not provide the required accuracy in setting the room temperature, (ii) its setting is not directly related to the actual room temperature since it is located inside the heater or air conditioner and mainly responds to the temperature inside the heater/air-conditioner, not to the temperature of the room and, it is the latter that needs to be controlled to implement the "10% per degree" rule in practice.
For heaters, this temperature control problem is illustrated in Figure 1, where the controls of a typical column heater are shown. Not only the arbitrary scale of the mechanical knob-dial type thermostat cannot provide the required one degree C accuracy in the room temperature setting, but also, being located within the heater enclosure, this thermostat regulates the temperature of the heater, not the temperature of the room. Indeed, the temperature within the enclosure of this heater, when it is in operation, can easily reach over 30-40 deg C, whereas the user would want to shut the heater off when the actual room temperature reaches e. g. 20 deg C, which this thermostat, unfortunately, cannot do.
Figure1. Controls of a typical column heater.
The above limitation means that the same thermostat setting on the majority of the existing heaters (i.e. the same heater temperature) will result in different room temperatures depending on the changing external and internal conditions from day to day and during the same day or night. As a result of such uncertainty, the mechanical thermostat needs frequent manual adjustment to try to keep the room temperature constant. A typical example of such manual adjustment is when parents of a baby need to come and check the temperature in their baby room and adjust the heater thermostat several times during the night to make sure that it is not too cold or hot for the baby. In this case the parents are approaching this issue from the point of view of safety and comfort for their baby. From the energy saving point of view, every time the room temperature exceeds the optimal temperature the energy is inevitably wasted and, day after day, this results in quite substantial cumulative additional energy costs.
It should be noted, that it is only recently, that the issues related to the room temperature control have began to come to light, largely driven by user attempts to manage the increasing electricity costs. In the meantime, there are still a large percentage of people, including professionals in the retail industry selling heating appliances, who are under a fairly common misconception that the knob style heater thermostat can actually control the room temperature. Only a relatively small percentage of users (e.g. those who have a thermometer in the room) have by now come to realise that a constant position of the heater thermostat does not mean a constant room temperature. This divides the general population of portable heater users into two broad categories: (i) those who believe that the heater thermostat can control the room temperature (the common misconception) and (ii) those who know that it cannot, but who are not aware of any better solution than to keep adjusting the thermostat manually. Both categories need help to save energy: category (i) needs education (to move into category (ii)), whereas category (ii) needs a workable solution.
The problem of room temperature control with the non-digital air-conditioners is generally similar. A typical non-digital window/wall air-conditioner is shown in Figure 2. As with the heaters, the knob thermostat does not provide the required degree C accuracy of the temperature setting. Furthermore, due to the fact that the room air intake grill (where the thermostat sensor is located) and the output grill (where cool air comes out) are located next to each other, as shown in Figure 2, the actual room temperature measurement that performed by this knob thermostat is somewhat questionable. These deficiencies can easily lead to a few degrees errors in temperature control which, in turn, can lead to energy losses in accordance with the "10% per degree" rule.
Figure 2. Control of a typical non-digital window/wall air-conditioner.
To summarise the above discussion, the required solution (i.e. apart from the constant manual adjustment of the knob thermostat of heater or air-conditioner) is that of the proper digital room temperature control, which implies that the user can set the desired room temperature with an accuracy of one degree C using a digital display (e.g. 20 degrees C for a heater or 24 degrees C for an air-conditioner) and that this room temperature will be maintained automatically regardless of the changing external/internal conditions.
To implement such digital room temperature control, two conditions must be satisfied: (i) the thermostat should have a digital display and controls to enable the required temperature setting with one degree accuracy and (ii) the temperature sensor should be reading the actual room temperature, not the temperature inside the heater or air-conditioner.
Tables 1 and 2 below provide a review of the different types of heaters and air-conditioners that are currently used in Australian households (existing user base) and also of the newer models of heaters and air-conditioners that came on the market in the last couple of years. The tables also contains rough estimates of availability of the digital temperature control in different types of heaters and air-conditioners, both in newer models and in the existing user base.
Table 1. Portable Heater types and % of digital temperature control.
|Portable heater type||Description||Pros||Cons||% of digital control in existing user base||% of digital control in latest models|
|Radiant||Emits infrared heat||Pleasant feeling of warmth||Not safe around children Not effective at heating larger rooms||None||None|
|Column (oil)||Heating element immersed in oil, safe to touch.||Safe Quiet||Takes longer to warm up room initially||None||None|
|Convection||Hot heating element in enclosure. Air is drawn into enclosure via convection.||Quick to warm up Quiet Relatively safe||Possible burning smell Fan noise (if fan driven)||<5%||30%|
|Fan||Heating element next to a fan||Quick to warm up||Fan Noise Burning smell||<5%||10%|
Table 2. Air-conditioner types and % of digital temperature control.
|Air conditioner type||Description||Pros||Cons||% of digital control in existing user base||% of digital control in latest models|
|Window/wall Single||Single aircon unit in wall or window||Inexpensive||Can be noisy Permanent installation required||20%||90%|
|Portable||Portable Single portable aircon unit with exhaust outside||Can be moved from room to room||Can be noisy Requires exhaust hose||50%||>95%|
It can be seen that heater and air-conditioner manufacturers have realised the importance of the digital room temperature control and, in case of air-conditioners, the majority of the newer models do feature a digital room temperature control. However, in case of heaters, only a relatively small percentage of the new models have digital room temperature control, whereas its prevalence in the existing user base remains very small (<5%) . Furthermore, some heater types, (e.g. column heaters, which are quite popular) simply do not have newer models with digital room temperature control for technical reasons. While the situation with the newer models of air-conditioners looks much better in terms of digital room temperature control, there are still several millions of working non-digital ("legacy") window/wall and portable air-conditioners, whose owners would very much like to benefit from the digital room temperature control without having to buy a new digital model.
Overall, it should be noted that many families either do not see the need or cannot afford to spend several hundreds of dollars on a newer, digital model of heater or air-conditioner and it is those families who would much prefer a cost-effective solution that would enable them to continue using their existing heating or cooling appliances, but without the penalty of the high electricity bills.
The device of the new technology presented in this paper is designed to provide the opportunity to retrofit the digital temperature control to any existing non-digitally controlled heater and air-conditioner, helping their users to save energy based on the "10% per degree" rule. The only requirement to the heater or air-conditioner to work with the digital plug-in thermostat of this new technology is that the appliance should be able to restart after power reconnection, which is the case for all non-digitally controlled units with a mechanical ON/OFF button.
The idea behind the solution is quite simple: instead of locating the room temperature sensor within the heater or air-conditioner, it should instead be located in an external thermostat, which is physically separated from the heater/air-conditioner and where the sensor is not influenced by the heat/cold that they generate. Furthermore, if this external thermostat is made to be digital, both of the problems discussed above, i.e. (i) the correct room temperature measurement and (ii) the accuracy of setting of the desired room temperature, are respectively solved. Finally, to enable a quick and easy set up by the user (i.e. to avoid any electrical wiring), the device should also be a "plug-in" type, whereby the thermostat could be plugged into a power outlet and the existing heater or air-conditioner could simply be plugged into it.
All these requirements are realised in a digital plug-in thermostat of the new technology, EnergySmart Thermostat - Heatermate, shown in Figure 3.
Figure 3. EnergySmart Thermostat, Heatermate, a plug-in digital thermostat - the key device of the new energy saving technology.
This plug-in electronic device simultaneously displays the current room temperature as well as the set room temperature, which can be adjusted by means of digital controls located on the front panel. These controls are also used to switch between Heating and Cooling modes for the device to be used to control a heater or an air-conditioner, respectively.
This is how it works for heaters. The user plugs the device (Heatermate) into the power point and plugs their electric heater into the Heatermate socket. He/she then sets the desired room temperature on the Heatermate display and leave the heater in the ON position, with its thermostat permanently set to maximum (e.g. to 10 out of 1 - 10 scale). With this maximum heater thermostat setting, the heater will produce the maximum heat output to heat up the room quickly and efficiently. Once the set room temperature is reached (e. g. 20 degrees C), Heatermate will disconnect the heater from the power and the heat will start to slowly dissipate within the room. After a while, when all heat is dissipated, the room begins to cool down. When its temperature drops by more than 1 degree below the set point (e.g. to 19 degrees C as in the above example), Heatermate will connect the heater back to power and the room will begin to warm up again. When the set room temperature (e. g. 20 degrees C) is reached, the Heatermate will disconnect the heater from the power and so on. Overall, Heatermate will cycle the heater on and off as necessary to maintain the set room temperature within one degree of the set point, e. g. between 19 and 20 degrees C. Such digital room temperature control delivered by Heatermate will provide the users of the existing non-digitally controlled heaters with the opportunity to save energy based on the "10% per degree" rule.
The operation of Heatermate with air-conditioners is similar, but reversed: the air-conditioner will be turned ON when the room temperature exceeds the set temperature by more than one degree C and turned OFF when the room temperature is lowered (the room is cooled down) to the set temperature. For example, if the set temperature is 24 degrees C, Heatermate will cycle the air-conditioner to maintain the room temperature between 24 and 25 degrees C, a similar performance to a permanently fixed electronic thermostat of a ducted reverse cycle air-conditioning system. In this case, however, to save energy a window/wall or portable air-conditioner is used to cool the one room which is used, not the entire house.
Figures 4 and 5 below illustrate the use of Heatermate with all heater and air-conditioner types, which are listed in Tables 1 and 2, respectively.
Figure 4 (below). The use of EnergySmart Thermostat – Heatermate, to retrofit digital temperature control to different types of non-digitally controlled electric heaters currently used in Australian households:
a.) – radiant; b.) – column; c.) – convection; d.) – fan.
Figure 4 (above). The use of EnergySmart Thermostat – Heatermate, to retrofit digital temperature control to different types of non-digitally controlled electric heaters currently used in Australian households:
b.) – radiant; b.) – column; c.) – convection; d.) – fan.
Figure 5 (below). The use of EnergySmart Thermostat – Heatermate, to retrofit digital temperature control to different types of non-digitally controlled air-conditioners currently used in Australian households:
a.) – window/wall; b.) – portable.
Figure 5 (above). The use of EnergySmart Thermostat – Heatermate, to retrofit digital temperature control to different types of non-digitally controlled air-conditioners currently used in Australian households:
a.) – window/wall; b.) – portable.
Expected energy savings
The "10% per degree" rule provides a good guide to the energy savings that can be achieved with the digital room temperature control once it is implemented / retrofitted using Heatermate plug-in thermostat. While the digital temperature control gives the user the required tools to cut their heating and cooling costs, the actual energy savings will ultimately depend on many factors as well as the choices that the user will make. These factors include the size of the room, the level of room insulation, the outside temperature, the heater power and its daily use, as well as the set room temperature, which is where "10% per degree" rule comes into play. The Table 3 below illustrates how these and other factors can affect the energy savings.
Table 3. Factors influencing the energy savings that can be achieved with Heatermate.
|Energy saving with Heatermate||Set Temp.||Outside Temp.||Heater power||Room insulation||Room size||Daily Heater use||Energy saving with Heatermate|
|24||Sub zero||0.5kW||Bad||>20m2||3 hours|
On can see that in a more favourable scenario, when an average size, reasonably insulated room is heated by a powerful heater (2.4kW) and the user is comfortable with 20 degrees C set room temperature – the energy savings delivered by Heatermate could be quite substantial. On the other hand, in a less favourable scenario, when a larger and not well insulated room is heated by a small heater (0.8kW) and the user prefers a higher room temperature (e.g. 23 deg. C), the Heatermate will not be able to deliver much energy savings since under these circumstances the heater will be struggling to reach the set room temperature and, correspondingly, Heatermate will keep it ON most of the time.
As a general rule, if the heater power and the room insulation are such that the heater is capable of heating the room to well over 25 degrees C when operating at full power, and if the user is comfortable with the set room temperature of around 20 degrees C, the energy savings delivered by Heatermate could be quite substantial. However, the reverse is also true i.e. If the heater is barely capable of reaching the set temperature (due to its low power, poor room insulation or the high set room temperature) than the energy savings will be correspondingly much less.
In order to make a qualitative estimate of the energy savings delivered by Heatermate we will need to take finite values of all the relevant factors for the purposes of such calculation and compare them with the available experimental data. While we will attempt to use more typical/average Australian conditions to try to capture a more general user situation, it should be understood that these conditions will inevitably vary from State to State, as well as within the States (e.g. coastal vs. inland areas).
An average in power, 1.5kW rated electric heater constantly operating for 9 hours a day (e.g. from 10pm to 7am) has a daily energy consumption of 1.5x9=13.5kWh.
Assuming that this heater is operated with 6/10 thermostat setting (this is a fairly conservative assumption since quite often the thermostat is set to 10/10 in an attempt to heat up the room faster), the heater will be ON proportionally less and the daily consumption will be 13.5x0.6=8.1kWh.
When Heatermate controls this electric heater to maintain a 12-14 sqm room at the temperature, as set on Heatermate display, of 20 degrees C and for an average Australian winter climate (night temperatures 5-10 degrees C), the daily consumption is reduced to around 3kWh (as supported by the experimental data shown below in Figure 6), providing daily savings of 5.1kWh. 3kWh daily energy consumption with Heatermate is the measured average figure: on some not so cold nights the consumption is less and on some colder nights it is more – Heatermate adjusts the consumption accordingly to maintain the 20°C set point regardless of the weather.
Average daily energy savings of 5.1kWh with Heatermate taken over 120 day heating season (mid May to mid September) will translate into a total energy savings of 5.1x120=612kWh per heating season per room.
Since the generation of 1 kWh of electricity requires the emission of around 1 kilogram of carbon dioxide, the above 612kWh of energy savings delivered by Heatermate will result in approx. 0.6 ton reduction of green house emissions per heating season per room.
Figure 6. Daily energy consumption reduction when using Heatermate in a Sydney home in July.
Figure 6 shows Heatermate testing results for a typical Sydney home. The data were taken over July month with Heatermate controlling a 1.5kW column heater with its power consumption measured daily by a plug-in Power meter before the heater was switched off in the morning. The heater was operated for 9 hours a day, from 10 pm to 7am with the set room temperature on the Heatermate display of 20 degrees C. The size of the room was approximately 13m2 and the room was reasonably well insulated (single glazed windows, but properly sealed + insulation in the ceiling + draught protector under the door).
The results demonstrate that the daily energy consumption changed from day to day, mainly depending on the weather, with the average consumption over the July month period of 3kWh. Also shown for comparison, is the power consumption of the uncontrolled heater with a permanent 6/10 thermostat setting. The average daily power consumption reduction that has been achieved by using Heatermate is quite considerable at 5.1kWh.
The above result may appear to some extent surprising. It indicates that, as a matter of fact, very little energy is required to keep a reasonably insulated room at a temperature of 19-20 deg C for a mild Australian winter climate (5-10 degrees C). With the individual room digital temperature control being largely unavailable until recently, this data represents a new insight into the energy savings when heating individual rooms. Based on this finding, considerable energy savings can be achieved by implementing a precise digital room temperature control with Heatermate: the controller will help to constantly deliver the precise small portions of energy/heat into the room and fine-tune them as the external/internal conditions change – a task that is impossible to perform manually.
The permanent setting of the heater thermostat at 6/10 taken as the average baseline energy comparison in the above experiments deserves a bit more discussion. This baseline energy consumption could be different in two ways. Some users set the heater thermostat to maximum trying to warm up the room quicker and then often forget to turn it down – in that case the energy savings with Heatermate will be larger than estimated. Another category of users are trying to adjust the thermostat on a daily basis depending the weather – in this case the energy savings with Heatermate will be less than estimated as the user is essentially trying to do the Heatermate job manually with varying degree of success. However, such manual adjustment is as tedious as it is impossible to do continuously, especially during the night time, and this situation does not appear to be representative of the majority of the users.
In regards of the Cooling applications, at present, there are no experimental data available on energy savings that can be achieved by controlling a non-digital air-conditioner with the digital plug-in thermostat of this new technology. Work is currently in progress to collect such data. However, by drawing on the analysis performed for heaters combined with the "10% per degree" rule, one can note that a precise room temperature control delivered by the plug-in thermostat will provide the user with the tools to save energy in Cooling applications as well. These energy savings will generally be greater for a more powerful air-conditioner/smaller room, a situation which is more prone to produce the unnecessary cooling, which the precise digital control helps to eliminate.
The graph in Figure 7 shows the projected energy savings from implementing this technology for the Heating applications only over the next 10 year period. While, ideally, every household with a non-digitally controlled heater would benefit from using this energy saving device, in reality, however, it will take time for the technology to become known and adopted. In Figure 7 this is represented by the annual adoption rate, which is defined as the percentage of the existing non-digital electric heaters that are retrofitted with the digital temperature control of this new technology per year. The number of electric heaters nationwide is taken as 10millions , but to obtain a more realistic picture, a "dormant heater" factor of 20% has been assumed to account for the heaters which are owned by the Australian households, but which are not used regularly for various reasons, reducing the total number of heaters to 8 millions. The energy savings from implementing the digital temperature control for one heater are taken as 612kWh per heating season, based on the above calculation.
Figure 7. Projected energy savings and the corresponding reduction in the Green House Emissions (GHE) from the adoption of this new technology for different annual adoption rates (Heating applications only).
One can see that the annual adoption rate makes large difference to the nationwide energy savings and the resultant reduction in the Green House Emissions (GHE). The adoption rate in turn will depend on the general awareness of this new technology, which currently has no comparables on the Australian market and is largely unknown. The above mentioned misconception about the knob heater thermostat, as the room temperature control tool, compounds the problem further and requires more effort to be placed into the education of the general population of the heater users to help them to save energy.
On a purely commercial basis, the digital plug-in thermostat of this new technology offers a good return on investment to the customers, with the purchase price of the device typically returning in less than one heating season via energy savings.
From the Government's perspective and its current policies directed at reducing country's carbon footprint, the cumulative expected reduction of the GHE of more than 3 million tons over the next 10 years from the adoption of this new technology is a good value proposition, given that the technology has already been developed, saving on investment in its R&D and commercialisation. What is required, however, is a relatively small investment into consumer education to help to increase the annual adoption rate of this new technology (Figure 7).
Overall, the new technology presented in this paper appears to be one of the win/win solutions both for the Government in its efforts to minimise the country's GHE and for the individual consumers, who are trying to mitigate the rising electricity prices and cut their power bills.
- A new technology, EnergySmart Thermostat – Heatermate, has been developed to solve the problem, which is facing millions of Australians: how to reduce the costs resulting from the use of portable heating/cooling appliances, which, in peak seasons, could account for up to 50% of household electricity consumption.
- Heatermate will help Australian families, including those living in the State of Victoria, to retrofit a digital room temperature control to any existing electric heater or air conditioner, providing the users with the thus far missing controls required to manage and reduce their heating/cooling costs.
- The new technology has the potential to help the State of Victoria families to mitigate the impact of the rising electricity costs, while making a sizable contribution to the reduction of the State's carbon footprint.
- It is recommended that (i) the information about this new technology is added to the energy saving education in the State of Victoria and (ii) plug-in digital thermostats are considered for including in the range of free energy saving products available to Victorian households who currently use portable heating and cooling appliances without the digital room temperature control.
1. BIS Shrapnel, 2002, The Household Appliances Marketing Australia, 2002-2004, Vol. 3: Climate Control – Consumer and Retailer surveys and forecasts.
Page last updated: 24/06/20