SAP Result

[SarahG]

We have just had our SAP report back based on our BR drawings and it has come back as 81 B. Does this sound ok for a new build house? I was looking at Ecology mortgages as they seem to be well recommend, but they only consider builds of 88 B and above. Our budget is limited but the report says we could invest x amount to bring the SAP rating up higher. It doesn't say what exactly we could do though.

 

The build is masonry with UFH downstairs, ASHP and a wood burner in the lounge. The report also suggest we need a front door with a u-value of 1.0, which seems quite low. I hope we can find one as we want a couple of small glazed panels in it. 

[Conor]

A few solar panels will get you up to 88. If you have a lot of glazing then a few more quid on triple glazed rather than double will make a difference. Fyi our front door is 0.6, but cost £3k.

 

The SAP system penalises ASHP because is a cost based system. You can look at individual elements and see what you can improve. Imho, that's where you architect comes in. Ask them how they'd get it up to an A rating.

 

Our old, 1970 semi was a C77 or something. So 81 for a new build ain't amazing.

Edited October 2, 2022 by Conor

[JohnMo]

81 B, isn't that good.  What are you U values, they will be in the report.  How is the house constructed.

 

With UFH you need a good, low U value, otherwise you will be paying to heat heat the earth below your house, as much as your house.

 

There may be things you can do to increase your rating easily and relatively cheaply.

[nod]

I’d perhaps try a different sap accessor 

We achieved 89 on our previous build 

No solar No MVRH Traditional build 

Gas boiler Double glazed 

Adding solar 7-9 k would have taken us up to 91 Neither here nor there 

 

As sap stands it’s a bit of a joke 

The final sap As built report has to take your word that you have built it to the original spec 

If you go to one of the online sap companies and tell them what you are looking to achieve They will produce a new report 

Ours told me not to include MVRH Just fit it and don’t show any windows as fixed as both will effect the sap 

Very much like air tests 
Lots of companies chasing the same business 

Treat both as Anotger bit of paper in the process 

[ProDave]

Our design SAP was I think 84, which I was disappointed with, but it made a lot of assumptions, including an assumed air tightness of 4ACH. 

 

Right at the end of the build, I got the as built SAP done by the same assessor.  For that I was able to provide all the finer details to replace the assumptions, every Uw value for all the windows, the actual tested air tightness reading, details of the exact stove and ASHP fitted , solar PV fitted, heating controls fitted (thermostat in every room gets a couple of points on the SAP even if totally pointless in a near passive house) etc

 

My instructions to the assessor were if it does not achieve an A rating, (92 or greater) then don't issue the EPC, instead discuss with me what improvements I need to make to get it to an A.  the final result was A94

 

Our BC inspector said it was the first A rating he had yet seen.

[Kelvin]

The as designed SAP is typically inefficient with lots of assumptions. Have you gone through it and checked what assumptions have been made. That said, I got my design SAP back last week and it was 92. 

[SarahG]

Thanks for the replies. 

 

@Conor I didn't realise ASHP penalises SAP, that goes against what is in my head that is a more environmentally friendly and the preferred option over gas. Seems strange to me! We don't have a lot of glazing, we have timber framed sash windows, I would guess they aren't the bet for thermal efficiency but we have to use them due to the conservation area we are in. We do have some fairly large patio doors- 4.5m x 2.5m. Would love solar panels but worried about the cost and they would also require us to go through a planning change.

 

@JohnMothese are the values in the report:

External walls 0.18

Ground floor 0.11

Slope roof 0.15

 

Front door 1.0

Glazed door 1.2

Windows 1.2

Half glazed doors 1.2

 

It does say on the report we can spend between £15k-£25k to achieve A 97, so it doesn't feel a million miles away. I guess it depends on whether it is worth it to us to do that. All we really want is to build a family home in our budget and for it to be reasonably efficient.

 

The house is standard brick and block, our architect said that the new BR are pretty close to Passivhaus anyway so we just said well go with the minimum we need to get through (budget in mind). So I guess I thought we would get higher than that.

 

In hindsight perhaps we should have said to the architect/SAP assessor we want to achieve mim 88. I'll discuss with the architect and see what changes we can make to get the 88.

 

@nod I was wondering who actually checks this after the build, I assume the building officer isn't going to check every single one of those values! Does seem a bit of a joke.

Edited October 2, 2022 by SarahG
typo

[JohnMo]

SAP is still based on old values for embedded carbon within electric generation, so gas wins with SAP scores.

 

U values look fine.

 

So where you can improve is against standard details, that remove thermal bridges, these are lintels, windows and door returns and heads.  So something to investigate. All low cost attention to detail.

 

Also airtightness, assuming you haven't given SAP an airtight target.  Again doesn't need to cost a lot, needs detailing early on and watch execution.

 

Things to watch with airtightness.

Anything better than I think 5 would drive you to MEV or dMEV, better than 3 MVHR.  Ventilation without going the MVHR would be better as a demand based MEV or dMEV system.  So something else to look at.

 

Other things are heating controls, certain ones will improve SAP score.

 

 

[nod]

59 minutes ago, SarahG said:

Thanks for the replies. 

 

@Conor I didn't realise ASHP penalises SAP, that goes against what is in my head that is a more environmentally friendly and the preferred option over gas. Seems strange to me! We don't have a lot of glazing, we have timber framed sash windows, I would guess they aren't the bet for thermal efficiency but we have to use them due to the conservation area we are in. We do have some fairly large patio doors- 4.5m x 2.5m. Would love solar panels but worried about the cost and they would also require us to go through a planning change.

 

@JohnMothese are the values in the report:

External walls 0.18

Ground floor 0.11

Slope roof 0.15

 

Front door 1.0

Glazed door 1.2

Windows 1.2

Half glazed doors 1.2

 

It does say on the report we can spend between £15k-£25k to achieve A 97, so it doesn't feel a million miles away. I guess it depends on whether it is worth it to us to do that. All we really want is to build a family home in our budget and for it to be reasonably efficient.

 

The house is standard brick and block, our architect said that the new BR are pretty close to Passivhaus anyway so we just said well go with the minimum we need to get through (budget in mind). So I guess I thought we would get higher than that.

 

In hindsight perhaps we should have said to the architect/SAP assessor we want to achieve mim 88. I'll discuss with the architect and see what changes we can make to get the 88.

 

@nod I was wondering who actually checks this after the build, I assume the building officer isn't going to check every single one of those values! Does seem a bit of a joke.

No one checks it 

BC has no interest in Sap 

Only that you are doing things correctly 

As with air tests Sap is pointless 

Paper pushing 

All on here will exceed what is required for airtightness and sap 

1 in 7 new homes on the sites I work on each day are required to do an air test It’s years since I’ve seen one being done Most are being done remotely and scoring around 2 

Not a level playing field 

 

While MVRH is super efficient and extremely cheap to run 

Opening a window is also efficient and uses no energy 

Bad for sap 😁

[SarahG]

Having chatted to architect this morning we are going to leave SAP report as it is, so unfortunately that will cross Ecology mortgages off our list! See other post about lenders  When we do the build we will pay attention to all those small details to hopefully improve the SAP outcome, or keep up with the one we have been projected!

 

Our air tightness is 5, but we can't make walls any thicker for added insulation or the rooms would be too small. @nod I would rather open a window than have MHVR personally! We could probably upgrade our windows and doors, but that will be budget dependant.

 

Glad the u-values look ok thanks @JohnMo 

[Kelvin]

Air tightness isn’t about thick walls and more insulation. That’s definitely an area for improvement. 

[nod]

1 hour ago, SarahG said:

Having chatted to architect this morning we are going to leave SAP report as it is, so unfortunately that will cross Ecology mortgages off our list! See other post about lenders  When we do the build we will pay attention to all those small details to hopefully improve the SAP outcome, or keep up with the one we have been projected!

 

Our air tightness is 5, but we can't make walls any thicker for added insulation or the rooms would be too small. @nod I would rather open a window than have MHVR personally! We could probably upgrade our windows and doors, but that will be budget dependant.

 

Glad the u-values look ok thanks @JohnMo 

I agree 

The amount of insulation on your walls will make no difference to airtightness 

Sealing around windows and doors will make a massive difference 

 

[saveasteading]

When it was new I met some of the people who set  up the SAP and EPC processes.    That made me realise that a lot of it  was illogical and rushed through.  Worse was that they didn't understand  a lot of what they were doing. In fact the excuses for anything wrong was that these were temporary  settings and would be changed. But they usually weren't.   We bought the calculation programme and played with it, and it is easy to improve figures by illogical decisions. Any use of electricity was penalised. Air conditioning is programmed in to any epc, whether installed or not. And so on.

Also it is clearly quite easy to get any epc assessment to say what you want. (This based purely on personal opinion and inspection of a property as compared to the certificate on the wall). Whether this was ignorance or worse I can't say.

 

Solar panels will score points whether in sun or shade, so I generally showed the ones that the client would be fitting in due course.

 

Fortunately I never had a project where the client demanded any particular figure so we only had to do what was best for the project and then find a way to meet the minimum pass mark without spending their money pointlessly.

 

The same logic applies to SBEM, where there are points for fluffy animals on site, or a bus stop being near, which are not usually in our control. 

 

All very annoying but hey, just make a good building.

 

 

                                                                                                                                                                                                                                                                        

[Kelvin]

Sure but a building that scores C77 will be worse and more costly to run than a building that scores A94 regardless. 
 

Like is often touted on here you take a fabric first approach spending your limited funds where it will have the most impact. In this case the air tightness target isn’t very ambitious and could easily be improved upon. 

[JamieG]

23 hours ago, SarahG said:

Thanks for the replies. 

 

@Conor I didn't realise ASHP penalises SAP, that goes against what is in my head that is a more environmentally friendly and the preferred option over gas. Seems strange to me! We don't have a lot of glazing, we have timber framed sash windows, I would guess they aren't the bet for thermal efficiency but we have to use them due to the conservation area we are in. We do have some fairly large patio doors- 4.5m x 2.5m. Would love solar panels but worried about the cost and they would also require us to go through a planning change.

 

@JohnMothese are the values in the report:

External walls 0.18

Ground floor 0.11

Slope roof 0.15

 

Front door 1.0

Glazed door 1.2

Windows 1.2

Half glazed doors 1.2

 

It does say on the report we can spend between £15k-£25k to achieve A 97, so it doesn't feel a million miles away. I guess it depends on whether it is worth it to us to do that. All we really want is to build a family home in our budget and for it to be reasonably efficient.

 

The house is standard brick and block, our architect said that the new BR are pretty close to Passivhaus anyway so we just said well go with the minimum we need to get through (budget in mind). So I guess I thought we would get higher than that.

 

In hindsight perhaps we should have said to the architect/SAP assessor we want to achieve mim 88. I'll discuss with the architect and see what changes we can make to get the 88.

 

@nod I was wondering who actually checks this after the build, I assume the building officer isn't going to check every single one of those values! Does seem a bit of a joke.

building regulations aren’t really anywhere near passivhaus standard. Our house which is designed as a passivhaus has a sap score of 118 and the airtightness was 0.18. 
 

We have an ashp and 50m2 of solar though. 

Edited October 3, 2022 by JamieG

[Radian]

9 minutes ago, JamieG said:

building regulations aren’t really anywhere near passivhaus standard. Our house which is designed as a passivhaus has a sap score of 118 and the airtightness was 0.18. 
 

We have an ashp and 50m2 of solar though. 

Hi JamieG, Is your house new or did you purchase it off someone? I'm only asking because it seems most BH PH members come here before they build anything. Just being nosey 😄

[SarahG]

19 minutes ago, JamieG said:

building regulations aren’t really anywhere near passivhaus standard. Our house which is designed as a passivhaus has a sap score of 118 and the airtightness was 0.18. 
 

We have an ashp and 50m2 of solar though. 

Yes, I thought his comment was a little strange. We didn't ask for an eco house, so he has done the job as we asked which is fine, but it isn't Passivhaus. An eco house used to be my dream, maybe one day  Anything over 100 is awesome.

[Andehh]

I'd love the see the difference in running costs between A90 and  A110.... maybe £20 a month? 

 

It's the ecofriendly top trumps... Who cares if you can't drive 220mph, it beats your 185mph....  

[JohnMo]

1 hour ago, JamieG said:

Our house which is designed as a passivhaus has a sap score of 118 and the airtightness was 0.18. 
 

We have an ashp and 50m2 of solar though. 

Your SAP is representative of having 50m2 of solar, not really being passiv or an airtightness of 0.18.  just about any house with 50m2 would be over the 100 SAP score.

[SarahG]

I worked out the suggested £25k we could spend to get an A rating would take 56 years to break even. Well depending on how energy prices go.

 

We are actually thinking about putting some pv panels on the roof of our new log cabin at the end of the garden. I wonder if somehow we could include them in the SAP report. We would need to get planning permission though (conservation area), so it won't be soon.

[Jilly]

See previous threads, there are some solar roof tiles/slates that are barely visible.

[SarahG]

I'm back to this again and looking for some more advice   So we have our suggested u-values for our windows and doors:

 

 

Front door 1.0

Glazed door 1.2

Windows 1.2

Half glazed doors 1.2

 

We have some concerns here. 

 

1. Do we have to use triple glazing to achieve these values?

2. If yes, we don't really want triple glazing for the following reasons- it is too thick and looks unattractive in a timber sash window, the cost is a lot higher than double glazing, the patio doors would need to be craned in due to the weight (I think?) so again a much higher cost, I also can't find many suppliers that supply u-values this low

 

Potentially we would prefer to have u-values of 1.4 and add some solar panels to offset this (can I do this, and should we do it now before we submit?).

 

Just wondered what other people's opinions were or any advice? I will of course talk to our architect, but would like to know what others on here think too.

[JohnMo]

1.  No, but many suppliers will want to offer 1.4.  Problem is not the glass but the frames, you need good frames to get 1.2 or better.  We have a couple of double glazed doors, which I had Krypton filled, they achieve U value for whole door of 1.1. An insulated door will get 1.0.

 

Increase insulation in floor, walls and roof.  Adding solar panels.  Adding waste water heat recovery. Better airtightness.  MVHR. Improved boiler controls. Will all get you more points on the SAP report.

 

 

[deancatherine09]

We have got Velfac triple glazed windows. All of them are below 1 with some of the larger fixed windows achieving around 0.7. Not too expensive either!

 

If you definitely want DG (I would urge you to reconsider) Velfac do that too, I am sure their U values will be decent as the frames are good.