Scotland ASHP and Victorian House

[Sunshine2020]

Hi,

New to the forum! Found lots of great information already.

 

We live quite rurally in the west of Scotland. Our house is victorian and relatively large but over years we've competed various renovations : 11kW solar, various insulation works, UFH downstairs, large cast iron radiators upstairs, part double glazing.

I'd ideally keep going with these and get rest of house double glazed etc. Our oil boiler has a small crack in heat exchanger though and I need to replace before the winter.

 

We've 3 phase power and I've been looking seriously at a higher temperature ASHP system rather than replace with another oil boiler.
Perhaps complimented with a Tesla Powerwall which would "store" the solar power.

 

I'm generally just looking for a little feedback and also if possible some recommendations on a trustworthy supplier that would cover Stirling area or a consultant that could help me design a specification we could use to get specific quotes.

 

I find conflicting views on ASHP and old houses.

 

Cost is a huge factor of course (upfront and running) but I am minded large old houses need a changed approach to heating and power and I want to do the right thing for the long term. 
We've no intention to sell or move etc.

 

Thanks for any help!

 

[SteamyTea]

26 minutes ago, Sunshine2020 said:

I've been looking seriously at a higher temperature ASHP system

You need to be care here, the 'high temperature' may come at the expense of efficiency, the CoP, or because it uses a normal resistance element to boost temperature.

 

First thing to do is a decent heat load analysis, then you can start to look at the cost of fitting a system.  It is a bit like buying a suitcase, small ones tend to cost less, but if they are not large enough for the job, they are useless.

[newhome]

I had a quote for a high temperature split system but it was incredibly expensive. The quote was double what it would cost for a lower temperature system. In the end I decided to stay with my existing system (it’s working so not the same situation you are in) because I couldn’t make the maths stack up. As the ASHP needs to be on over a long period the time of use tariffs weren’t that useful either so I decided against fitting one. If the maths changes in the future I may revisit this. 
 

 

 

[ash_scotland88]

We've been having quotes for a central heating install, large 206m2 1930s home. Cavity walls filled (we believe from what looks like patched holes and finding polystyrene balls in the garden, floating on top of drawns etc) and currently only some secondary glazing.
Mentioned ASHP to one heating engineer who "specialise" in this area too, his response was as expected. It would be costly to install, possible requiring two of the larger sized units and even then insulation and glazing would need to be improved before hand.
I've read on an other forum of one person who stripped their victorian house back to brick essentially and fully insulated it, combined bills before hand was £2.5k+ pa and afterwards are less than £1k.

[Marvin]

6 minutes ago, ash_scotland88 said:

We've been having quotes for a central heating install, large 206m2 1930s home. Cavity walls filled (we believe from what looks like patched holes and finding polystyrene balls in the garden, floating on top of drawns etc) and currently only some secondary glazing.
Mentioned ASHP to one heating engineer who "specialise" in this area too, his response was as expected. It would be costly to install, possible requiring two of the larger sized units and even then insulation and glazing would need to be improved before hand.
I've read on an other forum of one person who stripped their victorian house back to brick essentially and fully insulated it, combined bills before hand was £2.5k+ pa and afterwards are less than £1k.

Yes in my experience good insulation and airtightness is paramount.  good floor insulation is also important. Easiest is when the floors are timber suspended...

[Sunshine2020]

Thanks all. I can't make the maths stack up as things stand and the oil boiler failing is the main prompt - only read bits but assume oil boilers will become less and less popular over next 10 years or so and owners of old houses might get penalised a bit more for just burning more and more oil. We probably spend around £2.5k per year on oil at present and I'm realistic that ASHP might not be an incredible change here.

 

We do not have good airtightness but the whole of ground floor has insulation board below the UFH. We need a fair bit of double glazing and have quotes etc. - just the disruption that is really putting me off there.

 

A challenge is actually finding and speaking to someone who "knows" but doesn't have some other vested interest in selling or doesn't really have any actual experience with our property type. Really needing a bit of a holistic view with the solar etc.

 

The easy option is replace with another oil boiler and revisit in 10 years when everything more mature.

 

[Conor]

If you're going to all the bother and disruption, put triple glazing in rather than double. Sizable benefit for not much more money. And don't forget the airtightness tape!

 

Do what you can for draft proofing and insualtion in the house before (have you 400mm insualtion in your loft yet? Pumped cavities or external wall insulation?) you think about changing heating systems. 

[Sunshine2020]

Thanks Connor - loft is done, no cavity and we can't insulate externally (conservation area etc.). Internal insulation we are working on as and when but it's very disruptive.

 

The only prompt for change of boiler / heating soruce type is that existing one needs replaced. I'm leaning more towards just going with an oil boiler for now - cheaper and proven to be able to heat the house!