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Hello all,

 

Just had our SAP calculations done (I don't have anything windows, so couldn't use the free software) and we've been advised that its better to have a gas boiler fitted then use ASHP (brings us up form a C to a B). I thought ASHP would have been preferred? Anyone give any guidance on why this is?

 

TIA!

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ZacP    

 

looking to get our SAP calcs this week too, had a Quote for £165 (design PEA) then £135 for SAP / EPC on completion, how does that sound to you?

 

Sorry cant help with your question though!!

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@Critical Path I went with SAPeasy who were £168 inc vat for their expedited (24hr) service and have turned the report around in about 5 hours. Seem very good and helpful discussing spec levels etc in order to meet our required 85+. Their usual 4-5 day service is currently taking 7 days apparently as they're really busy and is £108.

 

Good luck!

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I spent a few hundred on a detailed Sap via our Architect 

I needed to get one in a hurry so I went the online route 

89 score It made me realize  how pointless a sap is I could have told him anything 
It’s a toss up between the sap and the air test as to which is the biggest Scam 

 

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Nod - yes I agree but need the SAP prediction for the Ecology Mortgage, not sure what score Ecology are expecting though, Anybody know?

 

Air tests - Developers tape / sheet everything up -  test it, un tape and let the leaks continue - another sham.

 

we have to play the game though !! I need their money...

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I think it is a little pointless, but it does give an indication of spec to make things reasonable energy efficient. This is the spec I gave them. Score 85 on the nose!

 

- Walls to be built in ICF with a u value of 0.14

- floor to be insulated raft u value of 0.11

- ceilings/roofs to be u value 0.13

- Windows to be u value of 1.3

- Heating/hot water to be UFH with Viessmann VITODENS 111-W gas boiler

- generic MVHR (haven't chosen specific model yet)

 

Just gives an idea of spec just in case anyone else needs it too!

 

@Critical Path I'll give you one guess at what minimum score Ecology need.... it begins with an 8 and ends in a 5..... 😉

Edited by ZacP

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The air test can be useful. On our last project we did two. One before lining the walls and one final when everything was done. The aim was to find our where we had leaks and fix them prior to the lining out. It was a timber frames house with dry lining. First run was 2.3 final just over 1. We fixed lots of things but the real problem was and remained the windows and doors. They were custom British made timber. Never again.

 

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What version of SAP are they using?

There's a few tricks/cheats you can look at to get decent scores - but it also needs a bit more input!

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No Idea, I have my score now and its where it needs to be for Ecology, so I'm happy. In a way (and this is probably bad) I don't really care how they got it. From what I can tell things may well change during the build and create change in a positive or negative direction way for the final EPC anyway. 

 

for example I'd rather have an ASHP but they said no, so I won't have one. Until it comes to being signed off then I might add one in later. 

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3 minutes ago, ZacP said:

No Idea, I have my score now and its where it needs to be for Ecology, so I'm happy. In a way (and this is probably bad) I don't really care how they got it. From what I can tell things may well change during the build and create change in a positive or negative direction way for the final EPC anyway. 

 

for example I'd rather have an ASHP but they said no, so I won't have one. Until it comes to being signed off then I might add one in later. 

 

The thing is, if you have no understanding of what changes will impact the SAP then how do you decide what changes you want to make?

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Because I don't really care about SAP values in their basic form, I care mainly about money leaving my bank account. If gas will mean less money leaves it then I'll keep it. If an ASHP will reduce our bills I'll do a basic cost benefit analysis and make a decision on that rather then some arbitrary number which doesn't mean much to me.

 

We're not doing this build to be 'eco', but more to be cost effective and cost efficient, sometime I think it's very easy to buy into better must be better when sometimes it isn't. 

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I understand that in the current version of SAP the score improves if you use mains gas.  It is also cheap to buy, install and maintain a gas combi and you get unlimited hot water.

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I claim to have no understanding of saps calcs. I have only ever had to get One. I got a reccomendation from a house building mate. When i spoke to the sap bloke he asked me what i wanted it to say. I said i didn't know but that the council BC bloke said i had to have one due to large bi-fold doors, and a very large roof light in the roof on an extension at my daughters. £149 quid and he emailed it to me that afternoon. It was several pages of math stuff, and the last page said pass,pass,pass etc. When i offered it to the BC bloke he simply asked me did it pass, and handed it back to me. Did'nt even look at it.

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6 hours ago, ZacP said:

I thought ASHP would have been preferred? Anyone give any guidance on why this is?

 

The SAP score is a cost index, higher values, B rather than C indicates a lower fuel cost. SAP uses a cost 0f 13.19p/Kwh for electricity and (where a value is not available on the PCDB, product characteristics database) a default COP of 1.7 for ASHP or a cost of 13.19/1.7 or 7.76p/Kwh. For gas SAP uses 3.48p/Kwh for gas  and primary energy factor (a measure of the amount of gas to give 1Kwh of output) of 1.22 and therefore a cost of 3.48 x 1.22 or 4.12p/Kwh. Thus gas will give a higher SAP score than an ASHP.

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1 hour ago, A_L said:

 

The SAP score is a cost index, higher values, B rather than C indicates a lower fuel cost. SAP uses a cost 0f 13.19p/Kwh for electricity and (where a value is not available on the PCDB, product characteristics database) a default COP of 1.7 for ASHP or a cost of 13.19/1.7 or 7.76p/Kwh. For gas SAP uses 3.48p/Kwh for gas  and primary energy factor (a measure of the amount of gas to give 1Kwh of output) of 1.22 and therefore a cost of 3.48 x 1.22 or 4.12p/Kwh. Thus gas will give a higher SAP score than an ASHP.

 

Ah ha! A minefield of information! Thanks! So using those calculations I would have to find an ASHP with a COP of around 3.5 to make it more cost effective? Obviously not taking into account the cost of purchase, installation and maintenance of either fuel type, or of course the long term change in fuel prices for each fuel type.

 

Edited by ZacP
SPG

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