SAP rating

[Thedreamer]

Hi everyone,

 

I need to achieve a SAP rating of 85+ to achieve lending on a Ecology self build mortgage. Would anybody be able to offer a view as what would be the most cost effective way to achieve this target?

 

Thanks

 

Kerry

 

 

 

 

[le-cerveau]

That is a loaded question!

What is your current SAP assessment, House construction methodology, Insulation, air tightness, ventilation, heating system, hot water system, renewable......

We need more data to be able to give any advice.

Generally, well insulated, reasonably air tight shell will have the most impact, plus if you have mains gas that helps (very counter intuitive).  Renewable's also add to the score (ie lots of PV).

[Trw144]

Hi - I believe you only need to show that you are aiming to achieve the sap rating of 85 plus (don't tell them any different though). Having said that, I would think 85 plus is quite easily achieved. If you do need extra points - I think Pv gets you quite a few points so just show some on the plans.

 

On a side not, it looks like ecology have lowered their sap lending criteria -  would recommend them if anyone is looking for a mortgage.

[Bitpipe]

2 minutes ago, Trw144 said:

Hi - I believe you only need to show that you are aiming to achieve the sap rating of 85 plus (don't tell them any different though). Having said that, I would think 85 plus is quite easily achieved. If you do need extra points - I think Pv gets you quite a few points so just show some on the plans.

 

On a side not, it looks like ecology have lowered their sap lending criteria -  would recommend them if anyone is looking for a mortgage.

 

Agree - we are Ecology customers and at application just had to show how we were planning to achieve the required standard. During the build you are on their standard rate, discounts are only applied once you can demonstrate (with EPC) that you have achieved the standard.

 

I used the FSAP tool to model the house and generate a target EPC, Jeremy wrote some guidelines on this in his blog I believe. You can play with u values for the fabric (walls, windows) plus add PV and system details (heating, MVHR etc).

 

Given our house was designed to near passive standards we qualified easily enough, Ecology did not dig into it at all. We actually achieved 91 on the EPC which was enough to trigger a modest rate discount.

 

Agree that they are great to deal with, very personal service. Also, for us, we had full freedom on how to draw down the loan amount  - whether the full sum from outset or chunks as we needed them. No surveys or questions asked, a simple email from us released the funds.

[Alex C]

My experience with ecology is very similar to above. I achieved 89 without solar pv on a passive spec build and then managed 101 with 5.5kw of pv. I was aiming for 100 for a discounted rate. I knew all along though that the discounted rate would only be for a few months as it is a 2 year mortgage period and I started the clock running on that one before I even knocked my old house down.

[Thedreamer]

Thanks firstly for the helpful comments.

 

I'm a first time builder and this our first step on the house ladder and therefore have to be realistic as to my budget.

 

I'm building in Skye so pretty limited with mortgage lenders. The house is a 1.5 storey (138sqm in total). My hot water system will be a ecocent heat recovery system. I plan to heat the house with a stove and some portable backup electric heaters in the winter. We will most likely have a split heat/air con unit in our main living area.

 

My design is a slight modification of a house that was built previously and I was able to check with the owner as to how often he needed heating and how the ecocent has performed.

 

If I reach Ecology minimum standard I would like to invest any contingency left in PV or possibly a micro small wind turbine and perhaps boost the SAP rating further before completion. 

 

Thanks

 

Kerry

 

[jack]

Waste water heat recovery is worth a few SAP points for not too much money.

[Thedreamer]

1 hour ago, jack said:

Waste water heat recovery is worth a few SAP points for not too much money.

 

I had considered this previously.

 

http://www.earthsaveproducts.com/product/waste-water-heat-recovery-unit/

 

Do you use this in your house? This might sound like a stupid question but do you know if you can link a shower and bathroom to the one waste water recovery device?

[Ferdinand]

On 26/09/2017 at 20:35, Thedreamer said:

f I reach Ecology minimum standard I would like to invest any contingency left in PV or possibly a micro small wind turbine and perhaps boost the SAP rating further before completion. 

 

Has any micro wind turbine ever been proven not to be a red herring except on a boat or offgrid setting?

 

While solar is proven, it may still be worth registering as FiT etc. I would go solar on that.

 

Ferdinand

[jack]

8 hours ago, Thedreamer said:

I had considered this previously.

 

http://www.earthsaveproducts.com/product/waste-water-heat-recovery-unit/

 

Do you use this in your house? This might sound like a stupid question but do you know if you can link a shower and bathroom to the one waste water recovery device?

 

No, we used a shower wastewater heat recovery unit like this (can't remember the actual brand - edited to add: think it was the Recoup Pipe+ HE), plumbed into the two showers we use the most. They offer a several percent increase in SAP rating, depending on size.

 

I believe the unit you're looking at is intended to collect heat from all wastewater, not just from showers. I don't know what it costs compared to the shower-only version, but I seem to recall that I didn't like the prospect of the inside of the whole house version gumming up with all sorts of 'orrible stuff over time. I don't doubt the shower recovery version will look pretty skanky on the inside as well, but in theory it's cleanable.

 

The other thing is that in our house, the main sources of hot water are showers, with the washing machine and dishwasher a distant second. Neither the washing machine nor the dishwasher are in positions that would have made connection to a whole house unit convenient. The shower unit just sits out of the way in the back of a cupboard in our utility room, which puts it midway between the two showers from which it drains.

 

Edited to add: @Thedreamer, look here and at page 12 of this document for some info on getting the most out of SAP with this technology.

[Thedreamer]

12 hours ago, jack said:

 

No, we used a shower wastewater heat recovery unit like this (can't remember the actual brand - edited to add: think it was the Recoup Pipe+ HE), plumbed into the two showers we use the most. They offer a several percent increase in SAP rating, depending on size.

 

I believe the unit you're looking at is intended to collect heat from all wastewater, not just from showers. I don't know what it costs compared to the shower-only version, but I seem to recall that I didn't like the prospect of the inside of the whole house version gumming up with all sorts of 'orrible stuff over time. I don't doubt the shower recovery version will look pretty skanky on the inside as well, but in theory it's cleanable.

 

The other thing is that in our house, the main sources of hot water are showers, with the washing machine and dishwasher a distant second. Neither the washing machine nor the dishwasher are in positions that would have made connection to a whole house unit convenient. The shower unit just sits out of the way in the back of a cupboard in our utility room, which puts it midway between the two showers from which it drains.

 

Edited to add: @Thedreamer, look here and at page 12 of this document for some info on getting the most out of SAP with this technology.

 Thanks that's really useful.

[TheMitchells]

Good luck on the build.  Can I ask you to look into the Passivhaus standard with the thought that it should not cost any extra to achieve.  there are plenty of examples now which prove that well built, low energy houses do not need to cost any more than a standard house yet you will end up with a healthier, more comfortable and cheaper house to run.  I can recommend the following magazine for plenty of articles giving inspiration as well as the exampes on BuildHub. 

 

https://passivehouseplus.ie/

 

[Thedreamer]

1 hour ago, TheMitchells said:

Good luck on the build.  Can I ask you to look into the Passivhaus standard with the thought that it should not cost any extra to achieve.  there are plenty of examples now which prove that well built, low energy houses do not need to cost any more than a standard house yet you will end up with a healthier, more comfortable and cheaper house to run.  I can recommend the following magazine for plenty of articles giving inspiration as well as the exampes on BuildHub. 

 

https://passivehouseplus.ie/

 

Thanks

[SuperJohnG]

Just cracking this thread open again as I am undergoing the same thing. 

 

I just done a predicated SAP rating with SAPEASY and it has come out at a 73C.

 

I have specced a kore insulated passive raft at 0.1 U value. 

External walls are 0.18 U value build up which is 169mm thick SIP panel. 

Roof is 0.12 build up to sloping ceilings with 194mm SIP panel.  

MVHR

ASHP

300LUVC

 

I guess i was assuming it would be higher off the bat. 

 

Only obvious thing I notice is the MVHR efficiency is at 70% when it can be 86% and the ACH rate is 2.5 and I am aiming for 1-1.5 hopefully?

 

They also said no overhang on windows, but I have a huge 3m canopy on the west face covering my 28m2 of glazed gable. Could that be having an effect?

 

Any hints appreciated.

 

 

Report here: 

 

 

[the_r_sole]

your sap report doesn't reflect the fabric uvaules you've said in the post?

[ADLIan]

The SAP rating is based on energy cost. Using an ASHP means electricity is the main fuel. Whilst this is the expensive option it is offset to a degree by the efficiency of the ASHP. The SAP calculation is not very sensitive to elemental U-values so lower U-values will have little effect on the SAP rating. MVHR unless correctly designed (and installed) can actually increase energy use (uses more energy than it saves) and negatively impact SAP rating and Bldg Reg compliance.

[Thedreamer]

Interesting looking back at this thread. In the end we had a SAP rating of 78 and used a different building society for the mortgage. 

 

Although we upgraded along the way slightly, I would expect our score to remain the same. Our built has around 20m2 of south facing glazing and our designer mentioned that this would help our score.  

 

There are loads on here who know more on this than me, but your report @SuperJohnG shows 6.00 for your air tightness I would have expected it to be a lot lower if you are having MHVR?

 

 

 

 

 

 

 

[SuperJohnG]

On 31/07/2020 at 13:56, the_r_sole said:

your sap report doesn't reflect the fabric uvaules you've said in the post?

 

@the_r_sole Thaks and I queried this with the SPA assesor who said 'The values shown in your screenshot is an "area-weighted averaged" value, which has taken the walls / roof areas in account respectively.'

 

On 02/08/2020 at 10:59, Thedreamer said:

There are loads on here who know more on this than me, but your report @SuperJohnG shows 6.00 for your air tightness I would have expected it to be a lot lower if you are having MHVR?

 

@Thedreamer I mentioend that to him and he has changed it, I suggested I was aiming fro 1-1.5, so he said he woudl put it to less than 2. Then ended up doing less than 3 in the fianl report he gave me for god knows what reason. 

 

In order to get it up to an an 86B from the previous number we made the following changes:

 

• Mitsubishi Ecodan heat pump specified (was a default heat pump)

• Vent-Axia Kinetic High Flow MVHR unit specified (was a default MVHR)

• Air test score = 3 or lower (was 6 or lower)

• 1kW south facing solar PV panels (was none)

 

This has ticked the box to predict as required, albeit I was hoping not to add Solar PV which is purely budget driven. We will see how it pops out once I get the Final SAP /EPC. 

 

thanks for the input