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Topic Title: Raising the rating of an Energy Performance Certificate
Topic Summary: New legislation 1st April 2018- Private rented houses and flats
Created On: 12 November 2017 10:08 AM
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 12 November 2017 10:08 AM
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sparkingchip

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Raising the rating on an energy performance certificate.

I am working on some flats belonging to a longstanding customer of mine and a letting agent who have bought the eight flats in a partnership.

One of the flats is heated by two storage heaters and one of them has packed up, so we were discussing replacing them. To cut it short I suggested two convection heaters with a boost fan, timer and thermostat, because the tenant is only at home overnight and the ceiling heights are ten foot, so the fans would destratify the air pulling the heat back down from the ceilings.

The letting agent landlord said no, because the flats already have a low EPC rating and convection heaters will hinder raising the rating and from the 1st April next year flats owned by private landlords will have to have a rating of E or more otherwise generally it will be illegal to rent them out.

There is a couple of provisos, these flats are a listed building so there are exceptions on the EPC requirements, also they have solid external walls and these are to be reassessed regards energy efficiency, then the flats within the building may be reassessed and given a higher EPC rating as explained here:

Residential landlords Association

My question is, what is the most energy efficient electric heating system for flats in a Georgian listed property with solid walls?

Andy Betteridge

Edited: 12 November 2017 at 10:17 AM by sparkingchip
 12 November 2017 10:33 AM
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sparkingchip

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To understand the situation, here as an example is a flat currently available to let in Worcester that it will be illegal to rent out to a new tenant after 1st April 2018, given the information in the current Energy Performance Certificate, less than five months from now:

Rightmove

Here is the EPC:

EPC

So given that it currently has electric convection heaters with integral time clocks and thermostats installed and there isn't a gas supply to the building, what would you consider the best upgrade to the heating system?

Andy Betteridge

Edited: 12 November 2017 at 11:01 AM by sparkingchip
 12 November 2017 10:43 AM
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sparkingchip

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The other thing to consider is:

Lot 20

Lot 20.

Some of the electric heaters currently installed will no longer be available and any new electric heating scheme needs to be installed using lot 20 compliant equipment.

Andy Betteridge.
 12 November 2017 11:48 AM
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sparkingchip

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Is it a matter of fact that only using new storage heaters running on an off peak tariff will improve the EPC rating of a property or can it be done using other electric heaters with good controls?



From the EPC Register.

Q. I have a very modern electric heating system in my home. However, in the summary section of my EPC 'Main Heating' has an energy efficiency rating of only 1 star - why is this?

The Energy Efficiency column in the summary section of the EPC is related to the cost of running the heating system. This takes into account the price of the fuel used (per kWh) and the efficiency of the heating system. Electricity is significantly more expensive than mains gas, which is one of the cheapest forms of fuel. For example, if a home has a mains gas boiler it will cost less to run than an electric boiler or electric storage heaters. The Energy Efficiency column informs the consumer about the heating system purely from a cost perspective. The ratings in the table will vary depending on the fuel used and the efficiency of the heating system. Even though an electric heating system may be 100% efficient at the point of use, turning all the electricity used into useful heat, it will still be more expensive for a homeowner to run than a 65% efficient mains gas boiler. A gas boiler will have heat losses associated in converting the burning fuel into useful heat for the property, but these losses are outweighed by the lower cost of mains gas

Q. My property is heated by conventional electric heaters and the EPC recommends the installation of storage heaters. The resultant change makes the Environmental Impact Rating worse rather than better - why is this?

Storage heaters are recommended as they are cheaper to run, making use of low-rate night-time electricity. However the total amount of electricity used by a storage heater system is greater than that used by conventional panel heaters. Therefore the resultant Energy Efficiency Rating is improved as running costs are reduced but the Environmental Impact Rating is made slightly worse as the total amount of energy used increases.

Andy Betteridge

Edited: 12 November 2017 at 12:03 PM by sparkingchip
 12 November 2017 12:02 PM
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sparkingchip

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Efficiency in electric heating.

Efficiency is a widely misunderstood term when it comes to electric heating. The fact is that electric energy is converted to heat with 100% efficiency at the point of use.

Therefore the actual efficiency of an electric heater - any electric heater - is 100%.

If you pay for 1kWh of electricity, 1kW of heat will be transferred into the room for one hour. This is dictated by one of the principal laws of physics, The Law of Conservation of Energy - "Energy cannot be created or destroyed, but can only change from one form to another."

However while it is true that all electric heaters are 100% efficient, they don't all operate in the same way.

For example an oil (or thermodynamic fluid) filled radiator has different performance characteristics to a panel convector heater.

The fluid in the radiator will transfer the heat uniformly around the radiator giving a higher proportion of radiant as opposed to convected heat in comparison to a convector heater. This is useful for certain applications, however the very small thermal storage capacity of a fluid filled radiator also results in slow release heat to the room during start up and a slightly prolonged release of heat to the room after switching off.

By comparison a radiator or panel convector heater with no fluid would release heat to the room more quickly during start up and stop releasing heat more quickly at "switch off".

Importantly in both cases they release exactly the same amount of energy to the room.

The European Commission Study of Local Room Heating products (DG Ener Lot 20) states: "Since the 'heat generation efficiency' is always 100%, it does not allow comparing the energy performance of electric room heaters."

The government's standard assessment procedure for energy rating of dwellings (SAP 2012 Version 9.92 Dec 2011) draws no distinction between panel, convector or radiant heaters, water or oil filled radiators, fan heaters or portable electric heaters - each has an efficiency of 100% and a responsiveness of 1.Dimplex

Andy Betteridge
 12 November 2017 12:55 PM
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sparkingchip

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So my question in the original post:

"My question is, what is the most energy efficient electric heating system for flats in a Georgian listed property with solid walls? "

is answered as they are all the same!

"The European Commission Study of Local Room Heating products (DG Ener Lot 20) states: "Since the 'heat generation efficiency' is always 100%, it does not allow comparing the energy performance of electric room heaters.
The government's standard assessment procedure for energy rating of dwellings (SAP 2012 Version 9.92 Dec 2011) draws no distinction between panel, convector or radiant heaters, water or oil filled radiators, fan heaters or portable electric heaters - each has an efficiency of 100% and a responsiveness of 1"

It's not what you do, but the way that you do it, that's what gets results!

Andy Betteridge

Edited: 12 November 2017 at 01:21 PM by sparkingchip
 12 November 2017 02:38 PM
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leckie

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When you look at the "is this product compliant" section in the link for. Lot 20, it gives various option. But it doesn't give the option of a 7-day time control and a thermostat/ electronic thermostat as a combined control, just either or. So maybe the Dimplex heaters with an integral thermostat and a 7-day time clock module that is linked to each heater via a pilot word is in fact compliant.

It als says that existing heaters are not affected, only new installations, or that's how I read it.
 12 November 2017 05:22 PM
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sparkingchip

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I have brought two different, but associated, soon to be compulsory legislation into the discussion, that isn't much of an discussion at the moment with me talking to myself; I am putting that down to not many people actually knowing what is going on. I foresee some landlords getting very upset when they actually find out they cannot rent out some houses and flats without making improvements to them.

Existing heaters without timers and with analogue timers are no longer going to be manufactured, that is part of Lot 20.

The EPC is based on cost to run, so the new storage heaters win everytime, because the electric is less than eight pence per kilowatt hour to charge them. The fancy wifi controlled electric radiators may be okay as may other heaters with good control systems, if the house or flat is really well insulated and everything else that is assessed for the EPC is good.

Replacing heaters alone may not sufficiently raise a the EPC rating of an flat or house that it will be illegal to rent out from F or G, but heating will always be a major consideration.

The standard rate electric heaters are ALL classed as poor as I understand it, but having good controls on them makes them a bit better, but not necessarily good enough, because they are consuming electric at the higher standard rate.

Andy Betteridge.
 12 November 2017 05:30 PM
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justinneedham

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Interesting..thanks for pointing out the Lot 20 stuff. I've had my head down and it had crept up on me.

On a related note (not really answering original question)... Do I assume this then means that all basic heaters which don't have integral controllers fitting the definitions needed, will then be outlawed? (For example I've recently installed a number of Herschel far-infrared panels using A.N.Other controllers). There are so many stand-alone options available, surely the industry must continue to build "basic/dumb" heaters to enable this flexibility for installers?

On the heating "efficiency" (misnomer), given the unavoidable physics that all electrical heating is 100% efficient, the only way to reduce energy input is to enable the space to cool down during unoccupied times. The ability to re-heat it quickly depends on the thermal mass. In many respects, a very low thermal mass (which is traditionally seen as a poor idea, but I sit on the fence) would greatly help in this respect, enabling fast temperature changes which would benefit the capability of an energy-saving thermostat/timer/activity sensor type control.
 12 November 2017 07:33 PM
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sparkingchip

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I don't know the answer to the issue of central controls on domestic electric heating system, at the moment I think that each new Lot 20 compliant heater will have integral time and heat controls, then these may be overridden by wifi controllers, I don't know if some can be overridden by a central controller connected by a pilot wire.

I phoned one manufacturer on Friday afternoon and asked the question how a expensive electric radiator can raise a EPC rating; and didn't actually get an answer. I believe that when assessed for a EPC it is just another electric heater with a timer and thermostat, so does not raise the rating at all, despite having a wifi connection and being expensive.

If I get time tomorrow I intend to have a chat with a fan assisted storage heater manufacturer and ask the same question again.

Andy Betteridge
 12 November 2017 07:34 PM
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sparkingchip

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Housing associations and homeowners don't have to improve their properties with low EPC ratings, only private landlords.

Andy Betteridge
 13 November 2017 09:02 AM
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mapj1

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Hmm - thanks for spotting this, its new to me and I must admit it seems to have aspects that come from the same stable as the thinking that a 1kW kettle is more efficient than a 3kW.. Which generally it isn't, its just slower.
There are some tricks that can be played with electric heating such as radiant heaters that warm the person in the beam rather than the fabric of the buildings, very effective in buildings of intermittent occupancy like church halls where to warm the brickwork takes longer than the meeting of folk within, and if you want to heat the inside of a building, and have the space to allow it, then pumping heat in at the expense of cooling something else.outside. But that is not what we have here.
In the case here, the idea that adding a timer to a heater saves energy may to the degree assumed, especially if it is switched on and off from elsewhere seems to be misplaced.

-------------------------
regards Mike
 13 November 2017 09:53 AM
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sparkingchip

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As I have tried to make clear there are two sets of legislation coming in.

Lot 20 means some basic electric heaters will no longer be available.

The minimum standards for private rented housing will make it illegal to rent out homes with a low EPC rating and electric heating is a issue that may need improvement amongst others.

Andy Betteridge
 13 November 2017 03:10 PM
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AJJewsbury

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Originally posted by: sparkingchip
:
Here is the EPC:
EPC
:

I'm confused - how can some of the "potential" ratings be worse than the "current" ones? (Overall CO2, Energy Use, Lighting etc)?

- Andy.
 13 November 2017 03:41 PM
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mapj1

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Interesting cert, seems odd not to recommend double glazing or secondary glazing, and maybe internal dry lining of external walls, before the heating.
Any kind of heating is cheaper during periods when not needed.

-------------------------
regards Mike
 13 November 2017 04:45 PM
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electric

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Andy

Yes, it does seem a little contradictory. We do not know all the detailed facts about the property in question, however here is a possible answer to how can some of the "potential" ratings be worse than the "current" ones? (Overall CO2, Energy Use, Lighting etc)?

The EPC in question related to a home heated by direct acting electric heaters. If we assume the property was on a standard single rate electricity tariff, then a potential change to electric storage heating and a dual rate tariff (ie Economy 7) COULD:-
a) Lower heating running costs, as heating energy would now be based upon the Off Peak KWH cost,
b) Increase the total KWHs used as storage heating is less controllable.
c) Increase lighting cost as dual rate peak time KWH cost is greater than standard rate tariff KWH cost.
d) Increase water heating cost if the current water heating system was not able to make full use of off peak times.

Ironically, when it comes to electric heating system type and design and associated tariff, running costs and overall energy consumption do not always go hand in hand. I.e. you can often use more energy, but overall pay less for it.

Kind regards

Chris

-------------------------
Kind regards, Chris
 13 November 2017 09:06 PM
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sparkingchip

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Originally posted by: AJJewsbury

Originally posted by: sparkingchip

:

Here is the EPC:

EPC

:



I'm confused - how can some of the "potential" ratings be worse than the "current" ones? (Overall CO2, Energy Use, Lighting etc)?



- Andy.


That's a building I know as one of my brothers rented a flat there for a couple of years.

As Chris just said with storage heaters you can use more electricity for less money, the EPC rating is based on cost, not saving polar bears.

Andy B.
 13 November 2017 11:51 PM
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electric

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Yes. it is interesting subject that has many variables.

The question original posted by Andy B "what is the most energy efficient electric heating system for flats in a Georgian listed property with solid walls?".--- Good question.

The EPC meaning of the term efficiency, is not efficiency in terms of the amount of energy used v heat produced, but in terms of the cost of that energy used v heat produced. Of course, the annual running cost of a heating system is paramount for most folk.

However unlike Gas, Oil, or LPG, the cost of electric heating can be far more variable due to the availability of tariffs that allow it to be sold at a different KWH price at certain periods throughout the 24hour day.

When designing a electric resistive heating system the house type, location, building fabric, and occupancy pattern have to be taken into account. Whilst direct acting electric heating maybe suitable for some properties, generally in a high heat loss property with a high occupancy pattern is not a good idea when it comes to running costs. The use of Off Peak tariffs is therefore favourable, and a good place to start is to first chose a suitable tariff, for example, Economy 7, or Economy 10, and then design the electric space and water heating system in conjunction with it, choosing appropriate equipment that will work, and take full advantage, of that tariff.

Going down the Off Peak route means to take maximum advantage of the Off Peak you have to have some sort of heat storage in the system. Ultimately, if the system can maximise Off Peak electricity, and you can closely control both the heat input to the store, and output to the property, then that is the most cost effective way.

Without going into too much fine detail, in Electricity Board days, a domestic mixed storage and direct acting heating system was designed to achieve following split in annual KWH consumption, depending upon tariff:-

a) For Economy 7 system, 90% of the annual space and water heating KWH consumption from Off Peak, and 10% from On peak

b) For Economy 10 system, 95% of the annual space and water heating KWH consumption from Off Peak, and 5 % from On peak

This would help assure low running costs, and the Board would publish running cost information for the house type concerned. (Their were other tariffs but lets just stay with these popular ones for now).

Some system designs would achieve this with less annual total KWH consumption than others, mainly due to their controllability. A good example would be a GEC Nightstore dry core electric boiler serving a wet radiator system as both the Off Peak electricity Input, and the heat output were both highly controllable, and the unit had exceptional heat retention with a very low standing heat loss, and what heat it did lose went into the house. These are no longer available.

More popular was the traditional storage heater and panel radiator systems, whereby fan assisted storage heaters gave the best controllability of the heat output, supplemented with direct acting panel radiators/convector heaters which were fitted with close control thermostats and a programmer. In essence, for resistive electric heating not much has changed from this concept today, except with modern aids, controllability is now at a more advanced level all round.

The Electricity Boards are long gone, but electric heating manufactures such as Dimplex still offer a heating design service.

The EPC will take into account the buildings fabric, primary heating energy source, heating system type, controllability, and apply a standard heating and hot water consumption assumptions. Of course those assumptions do not take into full account of the type of resident that is living in the property. There is a big difference for someone who spends most of their day and night at home and need constant warmth, and some one who just sleeps and eats breakfast at home. You can design a suitable "efficient" electric heating and hot water system for both, but a EPC cannot differentiate between them.

-------------------------
Kind regards, Chris
 15 November 2017 10:58 AM
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tjs2

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I understand that this will probably not be suitable for your case (due to the need to accommodate an outdoor unit) but this Mitsubishi mini split air source heat pump will put ~ 3 kW of heat into the room for a 600 W electrical load.

I'm not entirely sure how the EPC treats them, it may well be a bodge like most of RdSAP (which is used to create most EPCs). If RdSAP does allow you to take account of that unit's impressive SCOP of 5.5 then that'll definitely put a dent in the EPC.

Obviously way more upfront cost than the majority of electrical heaters (and unlikely that most landlords will be interested unless their hands are forced), but it'd be interesting to see what the pay back period is.

Edited: 15 November 2017 at 11:25 AM by tjs2
 15 November 2017 11:12 AM
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tjs2

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Originally posted by: sparkingchip
with storage heaters you can use more electricity for less money, the EPC rating is based on cost, not saving polar bears.
Andy B.


The UK grid is also usually "cleaner" during the economy 7 period than typical peak heating times, as you can see at:
https://www.electricitymap.org...country&countryCode=GB - although not by that much last night - quite often it's half the peak CO2 per kWh.
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