Heating advice for self build in Scotland

MikeJXE

I would be greatful for some advice from the knowledgeable posters on here.

My nephew is in the process of rebuilding a cottage in the Cairngorms national park and is unsure of how to heat it. 

He is not allowed to use gas or oil so is not sure of his best options, ASHP GSHP or Solar or what else or a mixture.

He is advised by LA to use ASHP

The property stands in about an acre of ground, is 2 bed 2 en-suite upstairs with dormer windows, 3 rooms plus bathroom plus porch on the ground floor. 

Roughly 140 square meters, new build highly insulated, 550mm thick walls with 150mm insulation. 200mm ground floor insulation. Mains electric on site and water is fed via a well. 

He has unlimited supply of logs and intends to install a log burner in the main lounge. Underfloor heating is installed on the ground floor and thinking of radiators upstairs. 

The property is built and is at first fix stage for electric and plumbing, electrics being fitted in the next couple of weeks. 

He is ground worker by trade so external works on GSHP would be of little cost to him if that helps.

Your assistance in this matter would be very much appreciated 

Thank you 

Rodders53

MikeJXE said:

He is ground worker by trade so external works on GSHP would be of little cost to him if that helps.

Seek advice from local installers-maintainers...

But GSHP will be more economic to run if much more costly to install due to groundworks required than ASHP in colder times.

thearchitect

This being Scotland, your nephew will already have had to confirm the proposed heating system at the time he made his application for Building Warrant.  Any change in the approved plans will require an Ammendment to Warrant to be submitted and he would be unwise to begin installation of that alternative until he is sure the building control authority is content.

The Scottish Government proposes to ban fuel-burning appliances in new private houses from 2024 onwards including, for reasons I do not quite understand, biomass systems.  Whether that survives committee scrutiny remains to be seen.

Electric (and hence, for example, GSHP) are therefore the only real show in town in the medium to longer term.   The problem is that parts of the Highlands can lose power following storms, albeit less frequently than the West Coast, so he should be giving thought to a back-up system.  That might be a genny, of course, but now is the time to be building it into the system.   It also requires to be included in the Warrant.

For those south of the Border, Scottish procedure does not allow work to commence without a warrant for anything of this scale and it is an offence (albeit rarely prosecuted) to do so.

MikeJXE

thearchitect said:

This being Scotland, your nephew will already have had to confirm the proposed heating system at the time he made his application for Building Warrant.  Any change in the approved plans will require an Ammendment to Warrant to be submitted and he would be unwise to begin installation of that alternative until he is sure the building control authority is content.

The Scottish Government proposes to ban fuel-burning appliances in private houses from 2024 onwards including, for reasons I do not quite understand, biomass systems.  Whether that survives committee scrutiny remains to be seen.

Electric (and hence, for example, GSHP) are therefore the only real show in town.   The problem is that parts of the Highlands can lose power following storms, albeit less frequently than the West Coast, so he should be giving thought to a back-up system.  That might be a genny, of course, but now is the time to be building it into the system.   It also requires to be included in the Warrant.

For those south of the Border, Scottish procedure does not allow work to commence without a warrant for anything of this scale and it is an offence (albeit rarely prosecuted) to do so.

Thank you for your reply.

I think he already knows that as ASHP has been specified but hoping for better alternative being acceptable.

He is not planning to install a different system at this stage and will go through the proper channels.

I have done some research and from my point of view (ex builder) ASHP might be the worst efficient as temperatures where he is can drop to -15 (not far from Grantown on Spey) in winter the time you need heat the most. 

He was thinking log burner plus solar but not clued up enough on any source to decide. 

ThisIsWeird

This is a rebuild, so presumably not considered a 'new' build with these restrictions?

Anyhoo, he clearly has enough room to build a dedicated biomass shed and store near the house? This, I understand, supplies a Thermal Store, so other heat sources can be added - the obvious one being the log burner. A PV system can add its bit via an immersion heater.

Someone, somewhere, will have a way of comparing the ongoing costs!

MikeJXE

ThisIsWeird said:

This is a rebuild, so presumably not considered a 'new' build with these restrictions?

Anyhoo, he clearly has enough room to build a dedicated biomass shed and store near the house? This, I understand, supplies a Thermal Store, so other heat sources can be added - the obvious one being the log burner. A PV system can add its bit via an immersion heater.

Someone, somewhere, will have a way of comparing the ongoing costs!

Thank you for the reply

I'm not sure if it's classed as a rebuild or a new build. It was an old cottage demolished mainly by the weather and the same design built on the same footprint, it does have an extension that is marked on the plans as a conservatory but with the same insulation as the main house and that houses the log burner. 

He has built a dedicated shed (highly insulated) adjoining the property 

Hopefully you're right and someone will have the information we need 

FreeBear

Rodders53 said:

MikeJXE said:

He is ground worker by trade so external works on GSHP would be of little cost to him if that helps.

Seek advice from local installers-maintainers...

But GSHP will be more economic to run if much more costly to install due to groundworks required than ASHP in colder times.

GSHP using boreholes would be my choice if the budget allowed. But up in the Cairngorms, I guess there is going to be some pretty tough rock to drill through.

BUFF

MikeJXE said:

He has unlimited supply of logs and intends to install a log burner in the main lounge. Underfloor heating is installed on the ground floor and thinking of radiators upstairs. 

if this is genuinely true then an obvious alternative solution would be biomass but an external boiler house/wood store within the National Park would afaik require planning permission.
Even with an ASHP at -15C I believe that a hybrid solution may be advisable as COP will drop. However, if the house is very highly insulated a stove may fulfill that.

ThisIsWeird

Not that you need telling, Mike, but since your nephew is a ground worker, if the decision is HeatPump, then GS is a no brainer :-)

UFH is ideal for such systems, but will obviously handle all types of energy source.

Should the decision be HP, then the upstairs rads will most likely require significantly up-sizing to run at the much lower temps provided by this system. 

weeg

I'd definitely add solar panels and a battery if he can. From my semi-educated perspective (my architect colleagues are working on me!) a really well insulated new build shouldn't need to much heating, so an ashp with mhvr should work.

FFHillbilly

Ground source heat pump looks like the best option, the normal downside to this (over ASHP) is the extra cost to install and the available ground space required, but your son has plenty of available space by the sounds of it and the ability to part install it to bring the cost down so it seems a no brainer.
one thing he will need to do though is find an MCS contractor who is willing to let him do the groundworks and still sign off on the job. i'm sure thats possible, but probably not all installers would do that.
and if the budget allows I'd recommend at least at the first fix stage to be completed for a PV array on the roof