BER Cert and secondary heat source

creedp

I am currently trying to finalise BER cert. As I was tight in achieving the 10 figure necessary for Part L compliance I was proposing to go with HP on its own as when I have a secondary heat source, the 10% heat output it takes from the HP brings me just under the 10 figure for Part L. I thought it was OK to go with a single heat source but my BER assessor has just advised that if I don't have a secondary heat source like a log stove then DEAP assumes I will use electricity as a back up heat source. This will obviously mean I will fail the Part L requirement. Is this correct?

I must have interpreted previous advice incorrectly which suggested that if I didn't install the stove in advance of the BER cert being finalised then the assessor would only take the HP into a/c in his assessment.

Also for Part L compliance I can only go with a log burning stove - a multi-fuel stove will fail. I want a Clearview stove which is sold as a log stove but can also burn coal etc. Will I be able to input the Clearview as a log burning stove or will it be seen as a multi-fuel stove?

This whole thing is getting ridiculous - the idea that if I install one kind of stove over another I will fail Part L. I intend burning wood and am purchasing the CLearview specifically for this purpose but will this be enough for DEAP purposes?

I'll be so glad to be finished with this carry on - at last hurdle now and just want to fall over it!!!

Thanks for any advice you can give

sydthebeat

creedp wrote: »

..... my BER assessor has just advised that if I don't have a secondary heat source like a log stove then DEAP assumes I will use electricity as a back up heat source. This will obviously mean I will fail the Part L requirement. Is this correct?

no, thats is not my understanding.

You ARE required to input a secondary heating system IF you have a fireplace, stove etc.
But you can always choose NOT to have a secondary heating source, and therefore no input for same.

DEAP states:
"The secondary heating system is based upon a room heater. Secondary heating systems are taken from the room heaters section of Table 4a . A secondary heating system is to be specified if:
a)
the main system is not sufficient in itself to heat the dwelling to the temperatures on which the DEAP is based
or b)
fixed secondary heaters are present (e.g. a gas fire, a chimney and hearth capable of supporting an open
fire or a solid fuel stove). "

So in the case of a Heat Pump, it will be more than efficient to heat the whole dwelling.
But if you have a stove or fireplace, you must input a secondary source.


tut tut on your assessor !!!

sydthebeat

creedp wrote: »

Will I be able to input the Clearview as a log burning stove or will it be seen as a multi-fuel stove?

From DEAP

2.2 When to select wood fuels in DEAP

As per section 10.3.3 of the DEAP manual, wood logs, pellets or chips may be selected as the fuel type for an appliance if its design is such as to prohibit the use of any other fuel type. This can be demonstrated by one
of the following:

Documentation showing that the product warranty is void if the product is used with any fuel type other than wood fuels ;

Listing of the product under http://www.hetas.co.uk/pdfs/Part_1_Appliances.pdf showing that the appliance burns wood fuels only.

In cases where there is any doubt about fuel type selection, then wood fuels should not be selected as the fuel type in DEAP assessments or for the purposes of demonstrating TGD L compliance. The appropriate choice of fuel should be made from one of option 2, 3 or 4 in DEAP manual Section 10.3.3.

Basically, it must be dedicated wood burning only.

creedp

sydthebeat wrote: »

no, thats is not my understanding.

You ARE required to input a secondary heating system IF you have a fireplace, stove etc.
But you can always choose NOT to have a secondary heating source, and therefore no input for same.

DEAP states:
"The secondary heating system is based upon a room heater. Secondary heating systems are taken from the room heaters section of Table 4a . A secondary heating system is to be specified if:
a)
the main system is not sufficient in itself to heat the dwelling to the temperatures on which the DEAP is based
or b)
fixed secondary heaters are present (e.g. a gas fire, a chimney and hearth capable of supporting an open
fire or a solid fuel stove). "

So in the case of a Heat Pump, it will be more than efficient to heat the whole dwelling.
But if you have a stove or fireplace, you must input a secondary source.


tut tut on your assessor !!!

Well that's very good news as now I can complete the BER without having to provide a secondary heat source from the start. I'm already a busted flush and need some time to recover! This is a good example to fit with my comment in relation to ' building facism'. The idea that you are being restricted to selecting from a very limited range of stoves simply because you have to qualify under Part L seems crazy. I want to burn wood but what happens in the very rare occasion I run out of wood and have been forced into installing a wood only stove? Surely its not necessary to be that restrictive for a secondary heat source? If its that problematic then put an extra duty on fossil fuels and encourage everyone, i.e including people in existing houses, with multi-fuel stoves to burn wood. Its the difference between the stick and carrot approach. the SEAI dont seem to understand this and yet they will give people massive grants to buy an electic car that is run from dirty electricity!

sydthebeat

its absolutley nothing to do with SEAI

this is a governmental building regulation requirement.

To me it makes complete sense. The regs require you to provide a portion of your demanded energy by renewable form. I dont agree with how they calculate this portion, but the goal posts are set as they currently are.

So, in order to meet the requirements, you need to analysis and synthesise different solutions. If wood, as a fuel, is to be considered renewable (which is a debate for another day) then there should be no deviation from it.
To me its pointless to consider a stove, which is a carbon producing heat source, as 'renewable' if it burns a fuel which has a high GWP.

what youve suggested about the carrot and stick approach already exists.. we call it carbon tax.

creedp

sydthebeat wrote: »

its absolutley nothing to do with SEAI

this is a governmental building regulation requirement.

To me it makes complete sense. The regs require you to provide a portion of your demanded energy by renewable form. I dont agree with how they calculate this portion, but the goal posts are set as they currently are.

So, in order to meet the requirements, you need to analysis and synthesise different solutions. If wood, as a fuel, is to be considered renewable (which is a debate for another day) then there should be no deviation from it.
To me its pointless to consider a stove, which is a carbon producing heat source, as 'renewable' if it burns a fuel which has a high GWP.

what youve suggested about the carrot and stick approach already exists.. we call it carbon tax.

One person's carbon tax is another person's tax! Agree with your point to a great extent however the current system focuses exclusively on new builds on two fronts. On the one hand they have to comply and bear the up front cost of much stricter regulations in relation to insulation etc. This significantly reduces the need for space heating in the first place, thereby reducing emissions and then are also hit with restrictions concerning secondary heating systems for these houses. At the same time we dole out significant grants to people to upgrade the insulation levels to a lessor std in existing houses while and allow then to have any kind of primary/secondary heating system they like without any restriction. As one guy doing A/T for me said he has done work for farmers upgrading their homes and getting significant grants making the job almost cost neutral while the front wheel of their tractor wouldn't even fit through the front door. So basically one set of restriction for one group and sod all for the next. Anyway as you will surmise I'm feeling rather sorry for myself:)

sydthebeat

creedp,

just checking again.... but any prov assessment ive done with a heat pump, even at min standards, it has absolutley walked the renewable requirement. usually ends up between 20-25 per sq m

are you inputting a heap pump with a low efficiency?? i think around the 300-310% efficiency mark the HP ceases to be 'renewable'

what efficiency are you inputting?

creedp

sydthebeat wrote: »

creedp,

just checking again.... but any prov assessment ive done with a heat pump, even at min standards, it has absolutley walked the renewable requirement. usually ends up between 20-25 per sq m

are you inputting a heap pump with a low efficiency?? i think around the 300-310% efficiency mark the HP ceases to be 'renewable'

what efficiency are you inputting?

The HP is rated at 385% on the HARP database which is disappointing because I see that the best performing brine to water HPs are rated at around 450%. That would certaintly make a big difference. The big problem for me (which should be the same for everyone) is the DHW heating which the HP is rated at 158.9% which means that my Delivered energy for DHW is 3,092 kWh/y and the Primary Energy is 8,347 kWh/. This compares to 2,027 kWh/y and 5,474 kWh/y respectively for space heating. So my big problem is with the DHW efficiency with energy requirements which seem extraordinary for a 300l cylinder. But there you are?

sydthebeat

thats not a great efficiency at all.... and thats where youre falling down badly.

has your assessor tried other avenues to get a better SPF fo rthat system?

if so, why select that heat pump?

creedp

sydthebeat wrote: »

thats not a great efficiency at all.... and thats where youre falling down badly.

has your assessor tried other avenues to get a better SPF fo rthat system?

if so, why select that heat pump?

I though the assessor could only operate off the HARP database so if it 385% there not much else that can be done. When selecting the heatpump I went with feedback from a couple of people I knew who found it reliable and efficient, i.e. low electricity bills. I was told official COP was 430% which wasn't extraordinary but up there with most. I knew nothing about HARP database at that time and actually the HP was only recorded on HARP from April of this year. Installer complains that manfacturer reduced the COP unnecessarily for HARP in order to have no issues with people complaining about stated efficiency but in any case I am where I am now and because of this I find myself in a bind with regard to Part L.

Another linked issue here is the DHW cylinder which my builder installed - its a Joule and the heat loss specified is 2.71 kw per 24hr. This seems high to me and is also impacting negatively on my rating. What heat loss would you normally expect for a 300L SS cylinder? Another issue I wasn't aware of and was told the cylinder was one of the best available .... nievety at its worst on my behalf:(

sydthebeat

creedp wrote: »

I though the assessor could only operate off the HARP database....

from SEAI

"The usual route for use of test data for heating systems in DEAP assessments is by use of data from the HARP database. Once a manufacturer successfully submits their heat pump information through the normal HARP application process, the heat pump Seasonal Performance Factor details will be displayed on the HARP Webpage. If a product is included on the HARP database, Assessors may use this information in a BER assessment as outlined in the DEAP Manual and they are not required to have a copy of appropriate test data from a suitably accredited laboratory or organisation.Alternatively, a Seasonal Performance Factor (SPF) based on accredited test data may be used in the BER assessment instead of the DEAP Table 4a defaults or HARP non-default value. In the case of brine/water, air/water or water/water heat pumps, this SPF is the mean COP for the test temperatures specified in the following document for the applicable system type when tested to EN14511-2. If inputting an SPF value, Assessors should ensure that they are using the appropriate test data from a suitably accredited laboratory or organisation for the heat pump model specified in the BER assessment. Manufacturer declared data is insufficient."

its a Joule and the heat loss specified is 2.71 kw per 24hr. This seems high to me and is also impacting negatively on my rating. What heat loss would you normally expect for a 300L SS cylinder?

that would work out at approx 60% better than the default value of 300 cylinder with 20mm insulation.
300 cylinder as default, storage losses = 1216 kWh/y
joule 300 cylinder, storage losses = 534 kWh/y

creedp

sydthebeat wrote: »

from SEAI

"The usual route for use of test data for heating systems in DEAP assessments is by use of data from the HARP database. Once a manufacturer successfully submits their heat pump information through the normal HARP application process, the heat pump Seasonal Performance Factor details will be displayed on the HARP Webpage. If a product is included on the HARP database, Assessors may use this information in a BER assessment as outlined in the DEAP Manual and they are not required to have a copy of appropriate test data from a suitably accredited laboratory or organisation.Alternatively, a Seasonal Performance Factor (SPF) based on accredited test data may be used in the BER assessment instead of the DEAP Table 4a defaults or HARP non-default value. In the case of brine/water, air/water or water/water heat pumps, this SPF is the mean COP for the test temperatures specified in the following document for the applicable system type when tested to EN14511-2. If inputting an SPF value, Assessors should ensure that they are using the appropriate test data from a suitably accredited laboratory or organisation for the heat pump model specified in the BER assessment. Manufacturer declared data is insufficient."





that would work out at approx 60% better than the default value of 300 cylinder with 20mm insulation.
300 cylinder as default, storage losses = 1216 kWh/y
joule 300 cylinder, storage losses = 534 kWh/y

Problem I have is that I don't have any other accredited results other that those provided by the company itself (i.e. a COP of 430%) and the Harp Database. I have asked the installer about this and as I said earlier he said he was aware of the problem and said it was the manufacturers who choose to submit this data to HARP .. this may be an overly simplisitic view of the process!

I'll work with the assessor to try to comply with Part L .. at this point the BER rating itself is irrelevant as long as above minimum requirements. Its shrug the shoulder time and walk away time for me I'm afraid. It has turned out to be a pretty disillusioning process.

Re: the Joule I was working it out at 2.71x365 = 989.15 kWh/y. Am I wrong?

sydthebeat

creedp wrote: »

Re: the Joule I was working it out at 2.71x365 = 989.15 kWh/y. Am I wrong?

you are correct, but when entered into deap there are adjustments made for the type of storage ie cylinder, and also the control system, ie cylinder stat and separate control of DHW and space.

this works out at 989 x 0.6 (for cylinder) x 0.9 (for controls) = 534 kWh/y

creedp

sydthebeat wrote: »

you are correct, but when entered into deap there are adjustments made for the type of storage ie cylinder, and also the control system, ie cylinder stat and separate control of DHW and space.

this works out at 989 x 0.6 (for cylinder) x 0.9 (for controls) = 534 kWh/y

You are correct of course Syd .. I have just looked at the DEAP spreadsheet! Thanks for that.

sydthebeat

creedp wrote: »

You are correct of course Syd .. I have just looked at the DEAP spreadsheet! Thanks for that.

creedp, im still amazed youre finding if difficult to reach the renewable requirement with what sounds like a well insulated, well controlled house... with a aheat pump energy source.

what thermal briding factor are you inputting?
what air change rate?
any hrv?
what rough floro area?

creedp

sydthebeat wrote: »

creedp, im still amazed youre finding if difficult to reach the renewable requirement with what sounds like a well insulated, well controlled house... with a aheat pump energy source.

what thermal briding factor are you inputting?
what air change rate?
any hrv?
what rough floro area?

Thermal Bridging is default 0.15
Air Change Rate 0.13 (2.64 m3/h at 50Pa)
Yes - ProAir SFP 0.9; Efficiency 90%
Rough floor area 265m2 (Vol 689m3)

THe HRV made an awful mess of the Part L figure becasue it was too efficient!! and reduced significantly the SH demand. So the problem I currently have is that I am putting in U value of 2 for windows instead of supplier figure if 1.4 because if I put in 1.4 my Part L would drop to 8.6 from 10.3. I'm loving this BER thing:)

creedp

creedp wrote: »

Thermal Bridging is default 0.15
Air Change Rate 0.13 (2.64 m3/h at 50Pa)
Yes - ProAir SFP 0.9; Efficiency 90%
Rough floor area 265m2 (Vol 689m3)

THe HRV made an awful mess of the Part L figure becasue it was too efficient!! and reduced significantly the SH demand. So the problem I currently have is that I am putting in U value of 2 for windows instead of supplier figure if 1.4 because if I put in 1.4 my Part L would drop to 8.6 from 10.3. I'm loving this BER thing:)

By the way Syd I checked the impact of inputting a HP at 450% and windows with a 1.4 u value into my calculations and found to my misery that I would have an A3 rating of 69 kWh/y and Part L result of 10.8. Bit of a difference! Even if I input the original quoted COP value of 430% I would have a 71 kWh/y A3 and a Part L 10.2. So the culprit is clear .. I'd better not tell the other half this as I would be lynched!!

sydthebeat

creedp wrote: »

Thermal Bridging is default 0.15
Air Change Rate 0.13 (2.64 m3/h at 50Pa)
Yes - ProAir SFP 0.9; Efficiency 90%
Rough floor area 265m2 (Vol 689m3)

THe HRV made an awful mess of the Part L figure becasue it was too efficient!! and reduced significantly the SH demand. So the problem I currently have is that I am putting in U value of 2 for windows instead of supplier figure if 1.4 because if I put in 1.4 my Part L would drop to 8.6 from 10.3. I'm loving this BER thing:)

Why in all thats holy are you inputting a TB factor of 0.15???
do, or did, you deliberately not intend on building in accordance with best practise?

why are you not inputting 0.08 here, it will make a world of differenced!!!!

air change is pretty good.... is that from results you currently have?

that window u value would mean automatic non compliance with elemental u values anyway... so forget about that. find your window supplier and input exact manufacturers data here.
1.4 is an ok window, but you can get better in a DG 16mm window.

im still not convinced that the HP the main detractor here.... theres lots of bad default values being used, which i cant understand why...

creedp

sydthebeat wrote: »

Why in all thats holy are you inputting a TB factor of 0.15???
do, or did, you deliberately not intend on building in accordance with best practise?

why are you not inputting 0.08 here, it will make a world of differenced!!!!

air change is pretty good.... is that from results you currently have?

that window u value would mean automatic non compliance with elemental u values anyway... so forget about that. find your window supplier and input exact manufacturers data here.
1.4 is an ok window, but you can get better in a DG 16mm window.

im still not convinced that the HP the main detractor here.... theres lots of bad default values being used, which i cant understand why...

Unfortunately Syd this is the work I should have had my assessor do forthe preliminary BER. I did get one done but I didn't know anything about cold bridging values amongst many other issues. He completed the BER and used those defaults. Unfortunately when I got a copy of the DEAP excel spreadsheet and started changing values I found that no matter what I did to improve BER rating I was continuously frustated by the Part L issue.

If I input the 0.08 cold bridge default, 1.4u for the windows, remove the default for 'a warm air heating system' under Pumps/fans in SH sheet I will end up with a reasonable BER rating of A3 (67 kWh/y) but my Part L is a chronic 6.4!! So what can I do? I can't understand this and short of installing a wad load of solar heating tubes I have no [known] way out of this predicament.

Btw the air change value is the offical one from my test. However, I know it can be improved because we found a leak from the attic where the cabling etc comes down from the attic - a 300mm sq channel which leads from the attic down to the ground floor ceiling - there was air gushing out from this source during the test - was not sealed off in any way!! When I seal this the real result will be much improved, however, I didn't bother trying to the job on the day of the test because the better the result the worse the Part L .. damm and blasted Part L!!

sydthebeat

creedp wrote: »

, remove the default for 'a warm air heating system' under Pumps/fans in SH sheet !

im not sure what you mean here??

do you mean your including no secondary hetaing system?

creedp

sydthebeat wrote: »

im not sure what you mean here??

do you mean your including no secondary hetaing system?

I am not specifying a secondary heating system at present. The 'warm air heating system' issue has been there from day one, i.e. when the preliminary BER was completed, and maybe I've got the wrong end of the stick here but I thought it related to the electricty consumed by the pumps/fans used to power a warm air heating system such as a MHRV with a heating element which is used to distribute heated air around a house or maybe a water to air system which distributes warm air rather than warm water around a house. I have neither so I'm of the view that this section under Space Heating - Pumps/fans - Is there a warm air heating system present? should be set to 'no'. It is currently at 'Yes' and results in electricity consumption of 413 kWh/y per year and Heat Gain [W] of 41 w.

Of course I might be wrong and maybe this should always be set to 'yes'?

sydthebeat

creedp wrote: »

I am not specifying a secondary heating system at present. The 'warm air heating system' issue has been there from day one, i.e. when the preliminary BER was completed, and maybe I've got the wrong end of the stick here but I thought it related to the electricty consumed by the pumps/fans used to power a warm air heating system such as a MHRV with a heating element which is used to distribute heated air around a house or maybe a water to air system which distributes warm air rather than warm water around a house. I have neither so I'm of the view that this section under Space Heating - Pumps/fans - Is there a warm air heating system present? should be set to 'no'. It is currently at 'Yes' and results in electricity consumption of 413 kWh/y per year and Heat Gain [W] of 41 w.

Of course I might be wrong and maybe this should always be set to 'yes'?

i though your heating systenm was a heat pump with UFH???

the MHRV system is not a heat system, its a ventilation method.
you should have 'no' here.
The energy consumption of the HRV system is accounted for in the ventilation workspace.

creedp, any chance of having a look at your xml file?

creedp

sydthebeat wrote: »

i though your heating systenm was a heat pump with UFH???

the MHRV system is not a heat system, its a ventilation method.
you should have 'no' here.
The energy consumption of the HRV system is accounted for in the ventilation workspace.

creedp, any chance of having a look at your xml file?

Another eg of my ineptitude is that the document I have is a excel spreadsheet and I can't attach it to a PM I was going to send to you.