Air to Water Pump- what's the ideal q50/BER rating?

jay0109

Hi

I just had my house externally insulated and the BER test has come back as a C1, up from C3 when a test was last done 4 yrs ago.
Also had an air tightness test and the result is a q50 of 8.23 and DEAP score of 0.41.

I was talking to a plumber who did some work in the house during the installation of the insulation (he's worked on a lot of A-t-W pump jumps for the SEAI) and he believes that my house would be suited to a A-t-W pump and at a rough estimate, it would cost €12k before grants. That would include piping, new rads and extra rads where required, zoned heating etc.
He did stress that underfloor insulation would be needed once the piping was done as there's none there at present (1960's house, suspended timber flooring).

My question: with a BER of C1 and the Q50 score of 8.23, is my house suitable for an A-t-W pump or is there a lot more work needed to seal the house?

Calahonda52

IMO you need to be down near 3 for a HP

jay0109

Got talking to the SEAI and no grants for the A-t-W pump unless at a B2 BER rating. In their experience, it won't work efficiently in a house with a lower rating than that. The electricity bills will be too high

Calahonda52

I don't work with BER so I don't know what impact a lower q50 will have on the BER for two identically built houses, except one say has a q50 of 8 and the other of 3.

Biker1

In order to qualify for the heat pump grant the Heat Loss Indicator calculated in DEAP needs to be 2 or below and has nothing to do with the overall energy rating of the house. This figure is based solely on the heat losses, one of which would be your air infiltration rate.
An airtightness test result of 8.3m3/hr/m2 is means you have a massive issue with heat loss and if you are in an exposed site this will make things worse. Have a technical assessor analyse the issues for you before you even consider a heat pump.

Calahonda52

Biker1 wrote: »

In order to qualify for the heat pump grant the Heat Loss Indicator calculated in DEAP needs to be 2 or below and has nothing to do with the overall energy rating of the house. This figure is based solely on the heat losses, one of which would be your air infiltration rate.
An airtightness test result of 8.3m3/hr/m2 is means you have a massive issue with heat loss and if you are in an exposed site this will make things worse. Have a technical assessor analyse the issues for you before you even consider a heat pump.

How is the HLI calculated?
The attached is from SEAI, which does use the insulation values so there must be a correlation between HLI and BER, albeit perhaps implicit, especially if its calculated in DEAP.

Biker1

The HLI is calculated from the fabric and ventilation heat loss. Can be done on an xls spread sheet. (Total heat loss/floor area/24) Just easier to do it in DEAP.

3d4life

jay0109 wrote: »

Hi.....
Also had an air tightness test and the result is a q50 of 8.23 and DEAP score of 0.41......

Does your house have ventilation by means of holes in its walls ?


If so, were these ventilation holes blocked up before the air tightness test ?

jay0109

3d4life wrote: »

Does your house have ventilation by means of holes in its walls ?


If so, were these ventilation holes blocked up before the air tightness test ?

I wasn't here when they did it. But I presume the relevant steps were followed as the lad doing the ATT was working for the SEAI and was here as part of their job in wrapping the house which included putting in wall vents where needed

MicktheMan

3d4life wrote: »

Does your house have ventilation by means of holes in its walls ?


If so, were these ventilation holes blocked up before the air tightness test ?

The testing standard calls for all designed ventilation be temporarily sealed for the test.

MicktheMan

jay0109 wrote: »

Hi

I just had my house externally insulated and the BER test has come back as a C1, up from C3 when a test was last done 4 yrs ago.
Also had an air tightness test and the result is a q50 of 8.23 and DEAP score of 0.41.

I was talking to a plumber who did some work in the house during the installation of the insulation (he's worked on a lot of A-t-W pump jumps for the SEAI) and he believes that my house would be suited to a A-t-W pump and at a rough estimate, it would cost €12k before grants. That would include piping, new rads and extra rads where required, zoned heating etc.
He did stress that underfloor insulation would be needed once the piping was done as there's none there at present (1960's house, suspended timber flooring).

My question: with a BER of C1 and the Q50 score of 8.23, is my house suitable for an A-t-W pump or is there a lot more work needed to seal the house?

Bolded part above is the main reason i would say for the v poor 8.2 Q50 result. Sort that out and you should be in a lot better shape.

jay0109

Yes, suspended timber floor has been identified as a major issue but I'm in a bit of a catch 22 on that. Insulate the floor now, which I plan to get done with or without an A-t-W pump, and get a long way towards the BER B2 rating. But then a good bit of that insulation will have to come back up as part of the A-t-W installation.
Because if i go the A-t-W route, I'll also need new rads and put in zoned heating. An overhaul of the pipe work throughout the house will be needed and a plumber I spoke with about the new system and the floor insulation, said the floor insulation really needs to happen after the pipework.

But it's the only way around this...insulate the floors first and a few other issues the BER through up. Then go through the BER again and hopefully have reached B2 stage. Then apply for A-t-W grants and installation

Water John

jay0109 wrote: »

Yes, suspended timber floor has been identified as a major issue but I'm in a bit of a catch 22 on that. Insulate the floor now, which I plan to get done with or without an A-t-W pump, and get a long way towards the BER B2 rating. But then a good bit of that insulation will have to come back up as part of the A-t-W installation.
Because if i go the A-t-W route, I'll also need new rads and put in zoned heating. An overhaul of the pipe work throughout the house will be needed and a plumber I spoke with about the new system and the floor insulation, said the floor insulation really needs to happen after the pipework.

But it's the only way around this...insulate the floors first and a few other issues the BER through up. Then go through the BER again and hopefully have reached B2 stage. Then apply for A-t-W grants and installation

In my memory, the DEAP software used in the BER calculation has a minus once you enter suspended floor in the system. So, I'm not sure can you avoid that.

3d4life

MicktheMan wrote: »

The testing standard calls for all designed ventilation be temporarily sealed for the test.

Yes, was hoping that this would be confirmed firsthand at time of test

jay0109

Water John wrote: »

In my memory, the DEAP software used in the BER calculation has a minus once you enter suspended floor in the system. So, I'm not sure can you avoid that.

Interesting. I might contact the lad who did the BER and ask him to run a back of an envelope calc on what the result would have been if the suspended floor was factored out

MicktheMan

jay0109 wrote: »

Yes, suspended timber floor has been identified as a major issue but I'm in a bit of a catch 22 on that. Insulate the floor now, which I plan to get done with or without an A-t-W pump, and get a long way towards the BER B2 rating. But then a good bit of that insulation will have to come back up as part of the A-t-W installation.
Because if i go the A-t-W route, I'll also need new rads and put in zoned heating. An overhaul of the pipe work throughout the house will be needed and a plumber I spoke with about the new system and the floor insulation, said the floor insulation really needs to happen after the pipework.

But it's the only way around this...insulate the floors first and a few other issues the BER through up. Then go through the BER again and hopefully have reached B2 stage. Then apply for A-t-W grants and installation

I don't understand your catch 22.
Why not have your ber assessor model the house with all the improvements included to ensure you will qualify for the grant. Then make the improvements to the house but include the distribution network at the same time. Apply for the grant and then install the hp.
Or am I missing something?

jay0109

MicktheMan wrote: »

I don't understand your catch 22.
Why not have your ber assessor model the house with all the improvements included to ensure you will qualify for the grant. Then make the improvements to the house but include the distribution network at the same time. Apply for the grant and then install the hp.
Or am I missing something?

Thanks Mick. Didn't realise (it could be done) or never thought of getting the BER assessor to remodel with the planned improvements built in.

But on your second point, I don't think you can apply for the SEAI grant retrospectively. I know your saying to leave the Pump element until after the grant application is approved but I'm not sure how I could risk getting all the necessary distribution work done first and then being turned down for the grant. It'd be a big hit.
I need to talk to a few plumbers about splitting the job up like that. It could work.

thanks