EPCs based on RdSAP - Evohome

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  • HenGus
    Automated Home Legend
    • May 2014
    • 1001

    #31
    This was the list that ElmHurst Energy provided me with. If it isn't on the list then it does not get taken into account:

    IMG_0624.jpg

    Comment

    • paulockenden
      Automated Home Legend
      • Apr 2015
      • 1719

      #32
      Do all EPC providers use the same database?

      Oh, and that appears to be a list of boiler manufacturers rather than smart heating controls.

      Comment

      • HenGus
        Automated Home Legend
        • May 2014
        • 1001

        #33
        Originally posted by paulockenden View Post
        Do all EPC providers use the same database?

        Oh, and that appears to be a list of boiler manufacturers rather than smart heating controls.
        It's confusing. I got this from BRE today in response to a question from me about responsibility:


        Quote: Thank you for contacting BRE.

        Unfortunately we no longer deal with EPC Assessments here at the BRE we sold this to Elmhurst Energy who deals with these. Unquote

        Elmhurst Energy has just responded with the following:

        Quote: The Building Research Establishment (BRE) is behind the software which is available to Domestic Energy Assessors. The rules about what should be included within an assessment are governed by the Government Department, the MHCLG, and published as RdSAP Conventions. Unquote

        I am even more confused given that my questions to BRE were about what does and doesn't get taken into account in an EPC assessment.

        Elmhurst said earlier:

        1. that the only main heating systems that will be awarded 5 stars, are boilers which also generate electricity (eg; Flow)

        2. Communicating TRVs can only be selected from the software if they are a brand which has been independently tested by the BRE. As you can see from the selection below, Honeywell has not had any of their heating controls subjected to this procedure, and only ‘ordinary’ TRVs can therefore be reflected in your EPC. (that is the graph posted above, which I agree looks like a list of boiler manufacturers)

        3. Smart/zoned heating controls are only available for selection if they have been tested by BRE.

        What I find interesting is that a lot of Honeywell products have been tested across the Channel. One would have thought that there would be a direct read across. I confess none of this makes a lot of sense and assessors do not have a clue. They just record what they they see and input the data.

        FWiW, my property came out at C - 80: 1 below a B.

        Comment

        • paulockenden
          Automated Home Legend
          • Apr 2015
          • 1719

          #34
          A bit of googling suggests that Elmhurst/BRE is just one supplier of EPC software / training.

          Others (for existing dwellings) include: NES, Northgate, Stroma, RICS, ECMK Ltd, Quidos, Heating and Ventilation Certificated Associates

          Maybe some of the others are more switched on when it comes to smart heating controls.

          Oh, and see page 32 of http://www.elmhurstenergy.co.uk/uplo...l_Aug_2016.pdf
          Last edited by paulockenden; 14 May 2018, 07:18 PM.

          Comment

          • HenGus
            Automated Home Legend
            • May 2014
            • 1001

            #35
            Originally posted by paulockenden View Post
            A bit of googling suggests that Elmhurst/BRE is just one supplier of EPC software / training.

            Others (for existing dwellings) include: NES, Northgate, Stroma, RICS, ECMK Ltd, Quidos, Heating and Ventilation Certificated Associates

            Maybe some of the others are more switched on when it comes to smart heating controls.
            If only: I was told that they all work to the same assessment criteria which comes from Government. My assessor was Stroma accredited, and he suggested that I contact BRE if I was unhappy with what he could and couldn’t include. BRE clearly do not like dealing with questions from homeowners.

            Comment

            • paulockenden
              Automated Home Legend
              • Apr 2015
              • 1719

              #36
              Don’t know if my edit crossed in the ether with your reply, but see that document I linked to. It specifically mentions zoned TRVs.

              Sounds like the software is just a load of tick boxes, and the operator isn’t given the chance to use his/her own intelligence.

              Comment

              • HenGus
                Automated Home Legend
                • May 2014
                • 1001

                #37
                Originally posted by paulockenden View Post
                Don’t know if my edit crossed in the ether with your reply, but see that document I linked to. It specifically mentions zoned TRVs.

                Sounds like the software is just a load of tick boxes, and the operator isn’t given the chance to use his/her own intelligence.
                Paul, I have been through the link ad nauseum. The problem with EPCs is encapsulated here:

                Programmable TRVs or communicating TRVs that are able to provide time and temperature zone control (conventional TRVs without a timing function provide only independent temperature control). In this case the device must be located in the database.

                Sadly, it’s a double whammy as far as I can see. Treating HR92s as default normal TRVs also defaults Evohome to single zone heating. There is a EPC SAP gain with 2 or more zones.

                It is just a tick box exercise. If something cannot be seen/measured or it is not in the database, then the EPC defaults to a conservative position. Full SAP for new homes is a more extensive/invasive assessment with leak tests etc. At the end of the day, RdSAP or SAP comes down to what Government thinks people will pay.

                Comment

                • HenGus
                  Automated Home Legend
                  • May 2014
                  • 1001

                  #38
                  Originally posted by paulockenden View Post
                  Don’t know if my edit crossed in the ether with your reply, but see that document I linked to. It specifically mentions zoned TRVs.

                  Sounds like the software is just a load of tick boxes, and the operator isn’t given the chance to use his/her own intelligence.
                  I have exchanged a few more e-mails with Elmhurst and got nowhere. As far as they are concerned, if a heating control hasn't been tested by BRE then it doesn't go in the EPC database. I pointed out that for marketing purposes, manufacturers can self-certify their products under the EU ErP Directive (now enshrined in UK Law) and lodge the supporting technical papers etc with the UK Office of Standards and Safety. It follows, why would any manufacturer want to pay BRE to confirm something that is already on public record?

                  To move things on, and to get something back which is definitive rather than a personal opinion, I have lodged a formal objection to my EPC on the basis that reasonable steps have not been taken in its preparation to ensure that it is accurate. I pointed out that all controls etc are clearly visible to the assessor, and ErP energy efficiency data is freely able on a Government website. I was also told this morning that whilst Elmhurst Energy is now responsible for the EPC Assessment Scheme, the raw EPC computer program that assessors use is still produced by BRE. A cynic might see a potential commercial conflict of interest.

                  Comment

                  • HenGus
                    Automated Home Legend
                    • May 2014
                    • 1001

                    #39
                    The latest Government-sponsored report from Loughborough University on heating controls states the following:

                    Most studies of usability focussed on central timers, room thermostats and programmable thermostats as a single device. Few mention TRVs or automation; no studies covered usability issues relating to weather compensators or optimisation. None identified, with any robustness, the consequence of poor usability in terms of energy or cost-effectiveness.

                    Overall, this review has identified a dearth of evidence relating to the energy savings, cost effectiveness and usability of heating controls in the UK literature. It isn’t that there are evidence gaps so much as no robust evidence at all for most controls.

                    Overall Conclusions

                    From the systematic scoping review conducted of UK relevant studies, the following conclusions can be drawn:

                     This review has identified a dearth of evidence relating to the energy savings, cost effectiveness and usability of heating controls. It isn’t that there are evidence gaps so much as no robust evidence at all for most controls.

                     Quantitative evidence has been generated from models, test houses, individual occupied homes and large-scale field trials of occupied homes.

                     Whilst large-scale trials in occupied homes could provide the most compelling evidence about the impact of controls, no such trials have been reported in the UK literature.

                     Adventitious use has been made of existing large-scale trials to indicate the effect of controls on room temperatures. It is not possible to infer the impact of the controls on energy demand.

                     Compelling evidence is emerging from side-by-side trials in well-characterised homes with synthetic occupancy. Such trials have demonstrated energy saving from zonal control for a particular chosen occupancy regimen.

                     Other side-by-side trials in experimental houses have shown that whole house thermostats can save energy as can the addition of TRVs. Whether timers and programmers save energy is unclear.

                     A large-scale field study in occupied homes showed no energy savings when TPI controllers were installed in place of standard room thermostats in homes with condensing boilers.

                     Usability studies focus on the requirements for users rather than the consequences of poor design. Consequently the energy impacts of a heating controller that is difficult to use are unknown.

                     A large-scale field study in Newcastle showed that in-home advice and an information leaflet did not significantly reduce gas consumption compared with residents that received no advice.

                     Large-scale field trials combining quantitative, measured data with qualitative surveys are needed, but these are expensive and need very careful planning.

                    There is an interesting table on page 33. My guess is that smart heating controls are not coming to the EPC process anytime soon. The bit that I do not understand is why the Government brought into Law The EcoDesign Regulations 2016 which classifies all energy-related products with the aim of increasing energy efficiency.

                    Comment

                    • DBMandrake
                      Automated Home Legend
                      • Sep 2014
                      • 2361

                      #40
                      Originally posted by HenGus View Post
                      The latest Government-sponsored report from Loughborough University on heating controls states the following:
                      Some interesting findings, and none particularly surprising I think. What we see is manufacturers quick to make claims of improved energy efficiency but no statistically valid testing to back that up. No surprise there!
                       Compelling evidence is emerging from side-by-side trials in well-characterised homes with synthetic occupancy. Such trials have demonstrated energy saving from zonal control for a particular chosen occupancy regimen.
                      In other words, energy savings from zoning such as Evohome depends highly on the occupancy pattern. If you are able to switch unused rooms off for long parts of the day (bedrooms during the day, downstairs during the night when bedrooms may be on) then there can be a significant benefit. If not, no.

                      A standard two zone upstairs downstairs split system will give you most of the daytime nighttime benefits, so if you go from that to fully zoned you'd only see a significant further improvement if you had a particular occupancy pattern that included unused downstairs rooms during the day etc. In my experience it takes significant tuning of your schedules to make significant gains - things like being willing to drop your bathroom temperature a bit outside of normal bathroom occupancy times like shower times. (you don't need the room toasty warm all day just in case for a short, randomly timed toilet stop)

                       Other side-by-side trials in experimental houses have shown that whole house thermostats can save energy as can the addition of TRVs. Whether timers and programmers save energy is unclear.
                      Why are reports still focusing on "the addition of TRV's" ? Surely they are mandated in building regulations for how long now ? Why would't you have TRV's of some description in all your rooms ? For that matter what house would't at least have a whole house thermostat ? Without some kind of thermostat temperature control of the house would just be guesswork requiring constant manual fiddling of the flow temperature with huge differences in temperature from one room to another.

                       A large-scale field study in occupied homes showed no energy savings when TPI controllers were installed in place of standard room thermostats in homes with condensing boilers.
                      I could have told them that. I've never bought the "TPI is more efficient" dogma. It's not. It's still just cycling the boiler on and off.

                      What it is, is a better way to modulate the heat output of a boiler under the control of a proportional thermostat system like Evohome, in the absence of an even better way to modulate boiler heat, such as OpenTherm. In essence it's a half step towards Opentherm for boilers that don't support Opentherm.

                      Compared to a traditional thermostat which fires the boiler continuously until the room is 1 degree over temperature, then leaves it off continuously until the room is under temp by 1 degree, (which can lead to a cycle time of anywhere between 30 minutes and 2 hours depending on room thermal characteristics) it will turn the boiler on and off typically every 10 minutes, varying the on time based on heat demand.

                      This prevents the large temperature swings that traditional controls cause, in theory TPI can maintain a very steady comfortable room temperature. It also prevents rooms that are manual TRV only from being starved of heat for long periods of time as there is usually at least some heat flow in any 10 minute period instead of potentially no heat flow for a couple of hours at a time. So it is great for comfort. It's not great for efficiency.

                      During each on period when the duty cycle is low the flow temperature is way below the flow temperature set on the front of the boiler, so the boiler will naturally run at full burn trying to get up to that set flow temperature quickly - and fail, because the TPI device will usually switch it off again before it gets there. Then by the time it comes on again the flow temperature will be low again so it will run full burn again trying in vain to reach the flow temperature.

                      So it will perform a series of short, full burn sessions trying to reach a target it can't get to. So the modulating boiler never gets a chance to modulate except under high load conditions!

                      Ironically with a traditional thermostat that might have a cycle time of more than an hour, the boiler will be able to reach its flow temperature and the run with a modulated burn rate for long periods of time.

                      The lack of the boiler being able to modulate its burner properly and the frequent on/off switching won't improve efficiency, if anything it might be slightly worse as there will be startup losses every time the burner re-lights.

                      OpenTherm on the other hand will call for a specific flow temperature when there is a low heat demand, this allows the boiler to run continuously in modulating mode where the burner is not running at full blast - this should in theory give slightly improved efficiency over TPI and yet still allow for proportional control, and a more responsive proportional control than TPI, which is slow to respond to changes in heat demand since the heat output is only an average across a 10 minute period with TPI.
                      Last edited by DBMandrake; 19 May 2018, 11:13 AM.

                      Comment

                      • HenGus
                        Automated Home Legend
                        • May 2014
                        • 1001

                        #41
                        Thanks. Your considered opinions are always of value. What I find interesting is that the new Boiler + regulations allow installers/consumers to satisfy the + bit with a smart controller which is likely to be ignored in an EPC assessment. It follows that someone who needs to raise a property’s EPC for letting purposes would be well advised to go for something other than a smart control. I have an open question with BRE whether Evohome is treated as two zones or a single thermostat? They have already confirmed that the HR92s are treated as standard TRVs.

                        Comment

                        • paulockenden
                          Automated Home Legend
                          • Apr 2015
                          • 1719

                          #42
                          For me, Evohome has always been primarily about comfort. Any savings (and there definitely HAVE been savings) are secondary.

                          P.

                          Comment

                          • DBMandrake
                            Automated Home Legend
                            • Sep 2014
                            • 2361

                            #43
                            Originally posted by paulockenden View Post
                            For me, Evohome has always been primarily about comfort. Any savings (and there definitely HAVE been savings) are secondary.
                            Same here.

                            Personally I think all the smart heating controls (not just Evohome) oversell the "save you money" angle, when the savings may be relatively small depending on your occupancy pattern, and willingness to learn how to optimise your schedule. (Not everyone is a heating theory nerd, hard to believe, I know... )

                            When you add in the considerable cost of buying and installing the equipment and the expected life time before it is either obsolete or starts breaking down, the total return on investment over a several year period is probably a negative number, in other words it has cost you more overall!

                            However, I think people only buying smart home controls in an often misguided attempt to save money is being short sighted, and overlooking the benefits of much better comfort, the ability to monitor and remote control your heating etc, which I now wouldn't like to give up.

                            People seem to be willing to spend money on fancy equipment to save them money (even if it won't in reality) but they're not interested in spending money to make their house more comfortable. How perverse... These same people may well spend a lot of money on expensive, comfortable furniture like sofas, chairs, carpets, beds etc, but aren't interested in spending money on heating system controls that make their house feel more comfortable unless it also saves them operating costs.

                            Is comfort from superior controls not a good reason on it's own for most people ? Would people buying a larger, more expensive, more comfortable car also expect that to save them running costs ?
                            Last edited by DBMandrake; 20 May 2018, 12:19 AM.

                            Comment

                            • HenGus
                              Automated Home Legend
                              • May 2014
                              • 1001

                              #44
                              Originally posted by DBMandrake View Post
                              Same here.

                              Personally I think all the smart heating controls (not just Evohome) oversell the "save you money" angle, when the savings may be relatively small depending on your occupancy pattern, and willingness to learn how to optimise your schedule. (Not everyone is a heating theory nerd, hard to believe, I know... )
                              The savings are indeed small; however, ErP for heating controls is enshrined in UK Law, under The EcoDesign Regulations 2016, with Evohome/OT/HR92 coming in with a 5% efficiency saving. Under Boiler + regulations, this would increase the seasonal efficiency of a 92% boiler to 97%. If a landlord is hoping that Evohome might get his property over the EPC classification threshold for letting, then he might be disappointed. Fitting a flue gas heat recovery system might be a better bet as these covered by SAP Appendix Q.

                              Comment

                              • HenGus
                                Automated Home Legend
                                • May 2014
                                • 1001

                                #45
                                An interesting set of comments from BRE about Evohome and how it is treated for EPC purposes:


                                WG - The SAP specification provides for a boiler efficiency credit for boilers connected to compensating boiler controls - see the SAP 2012 specification: www.bre.co.uk/sap2012 - From SAP 2012, the Product Characteristics Database (PCDB) has been used to record controls that satisfy the SAP definition for compensating controls (i.e. they're not TPI based controls and control the measured flow temperature) and are declared as being compatible with particular condensing boilers.

                                WG - The OpenTherm specification is not an energy saving mechanism in itself. The Product Characteristics Database records when boiler and compensating control manufacturers provide evidence of OpenTherm compatibility. For example, you will note that Danfoss have an OpenTherm certified control listed in the PCDB - see here: https://www.ncm-pcdb.org.uk/sap/pcdb...ype=371&pid=43. This means that a SAP assessor may select such a control with, for example, certain Ideal boilers and receive an efficiency credit

                                WG - Optimum start/stop is not a recognised energy saving mechanism. The SAP specification is based on idealised assumptions regarding a dwelling's operation and condition. This includes an assumption that, during standardised heating times the heating is simply on and the required temperature is immediately achieved..... any operational benefit from preheating a dwelling to achieve a temperature is not recognised. Such preheating would not be an energy saving.


                                I have been led to believe that as Evohome has not been assessed by BRE, then it will have been assessed as single thermostat and no zoning despite its published ErP rating of +5% efficiency (Class 8 device).

                                WG - Correct, the Honeywell Evohome has not been submitted to the PCDB by the manufacturer.


                                All ErP ratings, as you may know, are lodged with the UK Office for Safety and Standards which sits within BEIS.

                                WG - The Ecodesign regulation stipulates boiler efficiency credit for different classes of compensating control. Under the regulation, and at the point of sale, packages sold with such controls must be provided with a Package Label confirming the appropriate efficiency uplift provided by the Ecodesign control class and resultant efficiency for the package.

                                WG - There is no linkage between SAP (National Calculation Method for energy rating of dwellings) and Ecodesign control classes, nor is one required. However, you will note that from SAP 10 (to be published later this year), the specification will make explicit reference to Ecodesign control class definitions - see consultation version of the SAP-10 specification here: https://www.bre.co.uk/sap2016/page.jsp?id=3618.

                                WG - However, please note that, whilst the SAP-10 specification will make reference to Ecodesign control class definitions, the boiler efficiency credits prescribed by Ecodesign regulations are not based on a scientific method and not relevant to SAP, they are not therefore used.

                                Comment: Mis-selling on a grand scale me thinks.

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