@transparent thanks again!

I've been sending emails out this week to mutiple assessors who are listed a retrofit assessors for the PA2035 survey, so hopefully will get some traction on that soon!

Posted by: @transparent

I'll return here to comment on electric storage batteries if you like me to.

I'd love to hear you input on batteries! I'm currently uncertain about our options and which direction would be the best to go in e.g. I'd love to figure out the optimal battery size to maximise solar storage v cost of install. It seems as though battery usage is at complete opposite ends of the spectrum from winter to summer, with only 2-3 months of transition between the seasons where we'd get the best the efficiency of everything - i.e. good generation, good solar self consumption, good battery charge and moderate energy usage!!

In the summer the our is below 10kWh per day on average for 4-5months, so much energy not being utlised during the day and barely any battery cycling. Whereas in contrast to the winter, I estimate there's not enough solar to meet even 20% of usage, let alone put any charge into the battery! (based on my estimates to include ASHP usage)

I feel like more batteries is better than more solar, but only if making use of economy tarriffs to charge batteries at night! How easy is this to do? What additional factors do I need to consider for that kind of setup?

@squeakysim Yes, the floor for the upstairs room becomes 'internal' and the same for the ceiling of the downstairs rooms.

As for the hallway, I just put in my floor area, the total height of the tallest part of the hallway, and the window size. Essentially, treating it as a single large room. It's also now technically the hardest room to size a rad for in my place, but I'll just fit something large and leave it at that.

@squeakysim or I used heatpunk which is pretty good for the sizing calcs ... still haven't bought a heat pump yet  but at least I know how big I need. I think its authored by midsummerwholesale.co.uk

@squeakysim 450 is about the going rate - I have been quoted (and refused to pay) this kind of number myself, I understand why some ask for such it to offset their time cost, that may well not convert to an order , but I don't consider it reasonable in that anyone with the nouse to go on here asking for help in the exact way you are , should be able to work it out to get more or less the same number yourself using the free tools and the same method they would, you just need to measure and know the construction.

Posted by: @squeakysim

@transparent thanks again!

I've been sending emails out this week to mutiple assessors who are listed a retrofit assessors for the PA2035 survey, so hopefully will get some traction on that soon!

Posted by: @transparent

I'll return here to comment on electric storage batteries if you like me to.

I'd love to hear you input on batteries! I'm currently uncertain about our options and which direction would be the best to go in e.g. I'd love to figure out the optimal battery size to maximise solar storage v cost of install. It seems as though battery usage is at complete opposite ends of the spectrum from winter to summer, with only 2-3 months of transition between the seasons where we'd get the best the efficiency of everything - i.e. good generation, good solar self consumption, good battery charge and moderate energy usage!!

In the summer the our is below 10kWh per day on average for 4-5months, so much energy not being utlised during the day and barely any battery cycling. Whereas in contrast to the winter, I estimate there's not enough solar to meet even 20% of usage, let alone put any charge into the battery! (based on my estimates to include ASHP usage)

I feel like more batteries is better than more solar, but only if making use of economy tarriffs to charge batteries at night! How easy is this to do? What additional factors do I need to consider for that kind of setup?

the accepted wisdom is to put on as much solar as the roof will take. the bulk of the base cost is usually in the building work and installers time not the panels themselves, adding more panels is marginal cost. Then add batteries if money permits. If you use octopus go or similar electrical tariff as I do, you can charge battery overnight on cheap electricity (its just like an EV as far as the electric suppliers are concerned), and you can minimise / avoid buying peak rate electricity by running off battery during peak times . you need to do a lot of maths to figure out when it pays back, but with the current huge peak rate costs it can be surprisingly quick. depending on the battery brand this may be automated or something you have to setup yourself. one major problem however with batteries currently is lead times. Tesla are at 12months + for example.

I agree with @iancalderbank that £450 is about the right price for a survey undertaken by a PAS2035 surveyor to calculate the heat required for a dwelling.

But if I was going to pay that, then I'd want it from an independent 3rd party... not a prospective installer!

You really do need to have such a report done in such a way that all the options are illustrated. An installer will find it almost impossible to suggest a system architecture for a heat-pump which he doesn't offer himself!

Just look at the 71 alternative air-to-water heat-pump strategies which are offered by the one manufacturer Daikin. Then add in the multiplicity of options for hot water cylinders, valves and smart controls. It's important for your initial report to lead you towards the right solution for your site based on the thermal characteristics of the house and the most appropriate technology to meet your stated need.

In the case of @squeakysim I think the the option to monitor the site remotely (from Australia) is well worthwhile considering.

When I was looking over the shoulder of the 250 houses in which OVO installed ASHPs using funding from BEIS, it quickly became apparent that installers were regarding their work as completed once the HP was running. They took as little time as possible to attempt any optimisation, and didn't return to check operation a week or two later. The majority of home-owners had no idea whether their high running costs were indicative of an incorrect layout specification or a faulty component.

In the event, a home owner with sufficient technical understanding found a document in an Irish academic institution where it described the need to reduce the amount of 'cycling' which the heat-pump performed. Ideally this should be taken down to about 3-times per hour. Once the various different installations had this knowledge applied, the running costs fell substantially. I see no reason why remote-monitoring couldn't be undertaken both by @squeakysim and the UK-based installer who can have a technical discussion of any inefficiencies without even being on-site.

I’ve been away doing a lot of additional reading, watching you tube and sending email enquiries since the last time I was here! In addition to having a play with the heat loss calculation from sources provided here.

Which leads me to a question I’m looking for an answer on! 

I sent this heat loss to an installer and they’ve told me by regulation, the system has to be designed to 21c for all rooms except the bath (22c) or a store room (18c). Is this true…?!!

Considering mum prefer temp at 18-19, wouldn’t this be pointless…?

So do I just design the system to a higher flow temp to counter this?

@squeakysim, as part of MCS guidelines, systems must be designed to satisfy the following internal temperatures:

Living room 21C, dining room 21C, bedroom 18C, kitchen and toilets 18C, and bathroom 22C.

That’s supposed to ensure that a heat pump can adequately heat and maintain a property.

For the sake of @squeakysim who's in Australia, can someone point out why Heat Pumps should be installed by a contractor with MCS accreditation.

I'm clear on the reason for MCS companies doing PV solar-panels, because you need their reference number in order to claim the (pitifully small) pence per kWh which gets exported to the grid.

The rules for heat pumps elude me. I'm unsure what is the situation if any of the hardware and/or installer aren't registered with MCS.

@transparent, the quick answer is if you want your government grant as part of the Boiler Upgrade Scheme (BUS) the installers must be MCS accredited. There’s no other reason to get an MCS accredited installer as it doesn’t guarantee a competent installation.

@transparent I thought is was something to do with being able to claim the BUS..?

@mars that make at least more reasonable sense, this guy said all should be 21 except bath and storerooms! Are you able to direct me to those guidelines please?

I assume to compensate for this, you can just get it designed to a higher flow temp and then just keep it lower in the real world?