ASHP - Investigations and calculations

[Joeboy]

I don't know, but I guess not - the quote just says "Our Surveyor will perform a detailed assessment of your home that allows us to prepare your final system design"
It is a good idea - we've done some work on leaks, especially in the 80's lounge with suspended floor, an open fireplace & non-insulated cavities

I wouldn't think they would, more likely a tickbox scenario. I find the idea of the HP fascinating. I might have a crack at working out my own place in Scotland for kW req's. Is there a generic calculator to use?

I also bought another 3 rolls of the 1.5mm insulation strip we used at daughterlys in Edinburgh. The leak sealing makes such a difference as its 24/7 switch off. I'll be going back round our place next week.

Are you booked for a surveyor?

Not booked yet - I'm hoping to get someone round next week to look at cavity insulating the 80s part of the house before the survey - I think it would be better to have the insulation in place, rather than size the HP based on no insulation and then alter the way everything is calculated to work - maybe....

In terms of the calculation, I was given the MCS excel sheet from 2015 by my neighbour. You are very welcome to a copy of it if you like. It's not the most intuitive sheet in the world, but sure you could work it out

With only thought for your plan. A mate of mine over in NI as a RE nod had spray foam insulation done on his bungalow loft. He went to sell the house, sold it then all stop as mortgage lender wouldn't loan on the home due to the spray foam. He had the roof removed, insulation ripped out, inspected and sale went ahead. It cost him a fair skate of cash and a lot of stress.

I'm like Pavlov's dogs now when I hear about retro in wall insulation although I know there are more types than my mate had fitted. Worth mentioning I think?

[AGT]

https://aldas.co.uk/wp-content/uploads/ ... r-2022.pdf

[Swwils]

Do ewi

[AGT]

The OP is in a stone farmhouse I recall, maybe not keen on the external render look…

Likewise I have a whinstone property and wouldn’t consider EWI, just making do with internal renovations as funds/ time allows, trying to think of ways of reducing my consumption/impact

[Andy]

Rich,
Do Octopus run a vac test on your house or would you benefit from paying to have that done? I see the idea of low&slow working well on the HP but I think I'd also want to improve where I could after a leak test. Just a thought but maybe not practical?

We noticed huge differences across the home when actively hunting down leaks. There were SO many it would be embarrassing to list (maybe 60 to 80 leaks addressed).

The whole heat up/ cool down timings radically shifted in our favour. I didn't have a leak test performed but did multiple runs through the house clipboard in hand and over time addressed all that I could. Didn't cost much other than time but the returns were (are) insane. 1982 barrett bungalow extended 3 times.

I don't know, but I guess not - the quote just says "Our Surveyor will perform a detailed assessment of your home that allows us to prepare your final system design"
It is a good idea - we've done some work on leaks, especially in the 80's lounge with suspended floor, an open fireplace & non-insulated cavities

I wouldn't think they would, more likely a tickbox scenario. I find the idea of the HP fascinating. I might have a crack at working out my own place in Scotland for kW req's. Is there a generic calculator to use?

I also bought another 3 rolls of the 1.5mm insulation strip we used at daughterlys in Edinburgh. The leak sealing makes such a difference as its 24/7 switch off. I'll be going back round our place next week.

Are you booked for a surveyor?

Google 'Macs heat pump calculation spreadsheet' and you should be able to find the latest spreadsheet. It's simple to use and I've done a friends house in a few hours. It worked out fine with his heat pump. Just create rooms/dimensions etc. There is a drop down for common house build types for walls/roofs. You can also create your own build ups. It also does the design temperature for area as well. If you run into difficulties give me a shout. There is another document to use with it if you wanted to do boreholes and then work out the size required. I found a site that gives very detailed geology for scotland though I can't remember where. This is a good starter for working out the heat flow. This will be worse case round here as there is a reasonable through flow of water through the cracks in the granite. A friend in Torphins was close to the limit on his borehole as there was too much water flowing out! He has amazing stats on his 80's bungalow with a simple on/off GSHP. They are at the bottom of the hills though so a good bit of pressure.

[Andy]

Thanks for those ideas, Andy - good to know that yours can manage at -15 from a design goal of -6. Not sure about this idea of using the WBS less though - where's the fun in winter if you can't light a nice fire!

Thinking about how to measure the oil usage, I have Tado radiator valves, which give you an monthly usage estimate for M3 of (assumed) gas and cost for heating. I guess the gas quantity could be transferred into kWh pretty easily, maybe needs a slightly different % efficiency assumption. It also records a graph of individual room temperatures and when the boiler is on for each room - but not sure how I could output that data from the app. A quick web search suggests that there is an API which can be interrogated using a Github script.... but that's slightly past my knowledge level

You can always run a bit cooler in the house which will only help efficiencies. Then top up with the WBS. The system will back off to an extent once the stove is heating.

[richbee]

This is a useful resource I've been using to guage the impact of various insulation jobs.
It's allowed for a quick room by room approach throughout the house.

https://openenergymonitor.org/heatlossjs/

Thanks Pablo, that looks useful - and simpler than the MCS spreadhseet, as long as you know your U values for everything

[richbee]

I wouldn't think they would, more likely a tickbox scenario. I find the idea of the HP fascinating. I might have a crack at working out my own place in Scotland for kW req's. Is there a generic calculator to use?

I also bought another 3 rolls of the 1.5mm insulation strip we used at daughterlys in Edinburgh. The leak sealing makes such a difference as its 24/7 switch off. I'll be going back round our place next week.

Are you booked for a surveyor?

Not booked yet - I'm hoping to get someone round next week to look at cavity insulating the 80s part of the house before the survey - I think it would be better to have the insulation in place, rather than size the HP based on no insulation and then alter the way everything is calculated to work - maybe....

In terms of the calculation, I was given the MCS excel sheet from 2015 by my neighbour. You are very welcome to a copy of it if you like. It's not the most intuitive sheet in the world, but sure you could work it out

With only thought for your plan. A mate of mine over in NI as a RE nod had spray foam insulation done on his bungalow loft. He went to sell the house, sold it then all stop as mortgage lender wouldn't loan on the home due to the spray foam. He had the roof removed, insulation ripped out, inspected and sale went ahead. It cost him a fair skate of cash and a lot of stress.

I'm like Pavlov's dogs now when I hear about retro in wall insulation although I know there are more types than my mate had fitted. Worth mentioning I think?

Yes, thanks - I had also heard that it was often discouraged these days due to various issues with mineral fibre getting damp, polystyrene balls settling and leaving gaps, and the expanding foam rotting through galvanised wall ties! Someone on here suggested geocell glass bubbles - but I can't find much info, apart from one company who will supply it by the bag.....
Either way, I will see what the supplier says, if they recommend and what type, and what cost

[richbee]

The OP is in a stone farmhouse I recall, maybe not keen on the external render look…

Likewise I have a whinstone property and wouldn’t consider EWI, just making do with internal renovations as funds/ time allows, trying to think of ways of reducing my consumption/impact

You're right it is (mostly) stone, but it is already cement rendered, I guess about 1980 when the extension was put on. It would look much nicer if it was stone, but wouldn't really work with the breeze block extension.

External insulation would be the ultimate I guess, but I don't even want to think how complicated and expensive that would be.

I think a couple of the stone walls have some internal insulated plasterboard on the walls, but no idea how well it was applied or how effective it is. I might buy myself a cheapo thermal imaging camera and go round comparing!

[richbee]

Thanks for those ideas, Andy - good to know that yours can manage at -15 from a design goal of -6. Not sure about this idea of using the WBS less though - where's the fun in winter if you can't light a nice fire!

Thinking about how to measure the oil usage, I have Tado radiator valves, which give you an monthly usage estimate for M3 of (assumed) gas and cost for heating. I guess the gas quantity could be transferred into kWh pretty easily, maybe needs a slightly different % efficiency assumption. It also records a graph of individual room temperatures and when the boiler is on for each room - but not sure how I could output that data from the app. A quick web search suggests that there is an API which can be interrogated using a Github script.... but that's slightly past my knowledge level

You can always run a bit cooler in the house which will only help efficiencies. Then top up with the WBS. The system will back off to an extent once the stove is heating.

For me, this is part of the process, working out how we would use the ASHP - with and without WBS, how flexible you can be after installation, and how important it is to get all the basics right. eg. if you decide a room doesn't need to be as hot as other rooms, and size radiators accordingly, do you then need to increase the temp of the whole house if you then decide you do want it hotter after all?