Please read this blog from the bottom up!
After installing all these technologies, we received not just the EPC A rating we desired, but also a very warm, comfortable home and drastically reduced energy bills.
Based on December 2023 energy rates, we are looking at savings of £1,210 annually.

The heating system flow temperature is only at 25–35 Celsius, which keeps the house toasty, and we barely use the wood-burning stove anymore. Radiators are not too hot or too cold to be near (workstation beside radiator).
We are very happy that the house's carbon footprint is down from 2.7 tCO2e in 2020 to 0.6 tCO2e in 2022 and our running costs are only £350/year (plus £100/year gas standing charges for the gas hob).

General Learning Points

• Ensured we had a well-insulated draughtproof house before installing the heat pump – invested £10k over the years on insulation and £16k on new windows.
• Probably wouldn’t install solar thermal – PV generation through a heat pump can efficiently generate hot water.
• Current inverter can only produce 2.5kW from battery – made changes to how we use the kitchen ie a 3kW kettle changed to 1.5kW kettle (takes longer to boil) / don’t put the kettle and toaster on simultaneously
• Heat pump pulls 3kW on startup so cannot run 100% from battery.
• Participated in demand response periods – the utility company pays us for not using electricity at certain peak times in winter (heating setpoint lowered during period to ensure heat pump not operating / ensure battery full beforehand) – rates for saving electricity / discharging the battery to the grid can be over 400p/kWh.
• Still have gas installed for cooking hob but will probably change to induction saving £100/yr.
• Would now change wood burning stove to 3kW direct (external) air supply stove and seal up the floor vents.

Also see this information on the Energy Saving Trust Green Homes Network site:
https://greenhomesnetwork.energysavingtrust.org.uk/CaseStudy.aspx?cid=1677

Links for further reading.
Eco Retrofit - you want to eco retrofit your house but don't know how?
Cumbria Action for Sustainability https://cafs.org.uk/retrofit-made-easy/ are doing great work and have a lot of resources. Although they only operate in Cumbria, their on-line videos etc are still very helpful: www.youtube.com/@CumbriaActionForSustainability/videos Especially look at the 4 EcoRetrofit for Householders videos which are recorded webinars by experts.

General heating and heat pump design ideas:
We have found the Heat Geek very interesting in how to design and operate a heating system for our house. His site is: https://www.heatgeek.com/ and he has accredited a range of Heat Geek approved contractors around the country. If you like "how to" videos, his channel is www.youtube.com/@HeatGeek

Heat Pump consultancy:
For Fife and the Scottish central belt, if you have already addressed the draughts, insulation and windows in your house and are now looking to get a heat pump installed, then for a fee, Keith at www.theheatpumpguide.co.uk/ could survey your house, calculate your heat loads, work out the correct size heat pump, get contractors quotes, and support you through the install.

Weather compensation - if you want to learn more then look at Heat Geek videos above, but there is interesting data on https://energy-stats.uk/vaillant-arotherm-weather-curve-information/

An energy conscious household
We are now much more conscious about how much electricity we use. The electricity meter and heat meter measure the electricity in and total heat out of the heat pump. In 2022, it consumed 2,020kWh electricity and produced 7,162kWh of heat. In July, the solar thermal system produced 94% of all the hot water used, and 35% in December, meaning 67% of our annual hot water is produced by the solar panel.
A £180 Emporia metering system was installed on the electricity consumer unit, allowing an App to measure instantaneous power in every circuit in the home, The smart meter shows what the house is using, but this system shows what appliance or circuit is using the power. This enables reduction in energy use by turning off things not being used

Having a smart meter enables us to take advantage of different tariffs. The graph below details the time of day rates for Octopus Cosy showing two cheap rate periods and an expensive rate between 4pm and 7pm. The graph shows a day when the battery charges in the cheap rate periods and the house uses no grid electricity outside the cheap rate. Overall in a month the electricity in the house is costing approximately 20p/kWh. The graph shows the only grid electricity use on this day is to charge the battery in the cheap rate periods.

A summary of the Dec 2023 tariff

The "demand response" is when the grid is short of electrcity - typically a winter evening 5:30 - 7pm when the demand on the grid is expected to be high. Instead of starting a coal fired generator (typically), the national grid pays suppliers to reduce their demand. They do this by asking households to reduce their consumption for a specific 1 hr to 1.5 hr period and they pass on some of the payments the grid gives them. Consumers who have a smart meter can opt in and participate by turning off electricity using equipment during this period, or discharging their battery back to the grid during this time window. As I write this - yesterday we were credited £12 against our next bill for turning the house temperature down and discharging the battery for 1.5 hours.

Generating electricity from the sun
In 2022, I decided to investigate solar PV and battery. After extensive online research, I got four quotes from different suppliers, and chose EVi, a small, Fife-based installer, who I would recommend. The installation took two days, cost £10,000, and included the following:
10 Trina Vortex S 400W panels with Tigo optimisers totalling 4 kWp.

GivEnergy 3.6kW hybrid inverter installed in combe space.
GivEnergy 8.2kWh LiFePO4 battery storage system (maximum size single battery available from GivEnergy at time of install).
The battery is 94% efficient in charge / discharge cycle

The solar PV hybrid inverter produces up to 3.6kW of electricity, but the battery can only discharge at 2.5kW. In summer, the solar powers the house and charges the battery for use after the sun goes down. In winter, the battery is charged on cheap-rate electricity and used to run the house during the day.

• Initially daily look at graphs / now just content all works.
• Operation changes winter / summer and with tariff
• Now on Octopus Cosy but have been on Flux and an EV tariff – in winter charge both EV and battery fully between 4-7am @16.1p/kWh
  

• In summer the battery stores PV generation during the day for use overnight, so electricity bills show only export to grid

 
When system was installed export rate was 4.5p/kWh, so ran system to maximise self use of PV, but now getting 15p/kWh for export, so cheaper to charge EV at night than charge off PV during day even in summer.
We assumed we would get “island mode” capability (running building off the battery in event of power failure) – would now insist on external earth during install (retrofit very expensive).
Would now install at least a 13.5kWh battery and inverter capable of delivering up to 6.5kW & island mode, to maximise use of solar generation in spring and autumn, and to take better advantage of variable time of day tariffs.

The software can also predict the solar generation three days in advanced based on weather forecasts which could allow for different battery charging regimes. Differences can be due to local clouds or shading.

Summary

• 4kWp Solar PV (10 panels)
• 3.6kW hybrid inverter & 8kWh battery installed in combe space
• Sized to maximise renewable energy use.
• Easy to change charging / discharge strategy in App and website.
  

I had previously intended to install electronic controls on all the radiators to allow for zonal heating, but after some research opted for a single Vaillant control system instead, which works well.
The installation also included a Sontex Supercal Heat Meter to measure the heat delivered by the heat pump.

An Eastron electricity meter measures the electricity to the heat pump Along with the heat meter, this has allowed accurate monitoring of heat pump performance and Seasonal Coefficient of Performance,
COP = 2.5 for hot water and 3.5 overall.
The Passivliving data gateway sent energy data to BEIS as part of the project for two years.

New Radiators: Stelrad Elite K3 radiators were installed.
Sizing radiators for low temperature operation is very important and will significantly improve the operation of a heat pump.

In general radiators need to be up to 3 times the size to operate at low temperatures. These two radiators replaced a single double one in the lounge. Increasing the size of radiators would improve energy efficiency of any heating system by enabling the circulation flow temperature to be reduced. Even with a gas system or combi boiler this would increase condensing and efficiency using less gas to heat the house.
We were initially worried the larger radiators would be too intrusive, but we no longer notice them.

Joule twin coil 200L hot water cylinder
This cylinder is pre-insulated, but building an insulated box around it decreases the heat loss by an estimated 10-15% - taken from drop in tank top, middle and bottom water temperatures overnight.

Replacing existing vented system with unvented mains pressure cylinder means all tanks in loft can be removed. This also minimises the risk of pipes freezing in the loft.

Heat Pump installation - In 2021, I saw the Department for Business, Energy and Industrial Strategy's (BEIS) Electrification of Heat project on Facebook, which offered free heat pump installation. I applied for it and was accepted, which resulted in having the following installed by McInnes Group:

• 7kW Vaillant AroTherm Plus, installed by BEIS Electrification of Heat project.
• New heating system, all radiators 3x size with TRVs
• Low temperature continuous heating is superb – creates much better living environment than radiators that are too hot to touch and are only on for short periods of time.
• App easy to use for day-to-day changes.

Vaillant aroTHERM plus 7kW air source heat pump – installed to the rear of the property (North) as required for permitted development.
The preference from an energy point of view is the south exposure which gets more solar radiation and so will have warmer outside air.

After a year there was an issue with leaking air vent after a service. The symptoms were a repeated loss of system pressure causing the heat pump to lock out. Topping up the system let the heat pump start working, but the pressure loss always happened when we were away from the house. The vent was installed in a difficult to reach location and the dripping water/glycol fluid not noticed. After diagnosis, the vent was replaced and moved to a more convient location for servicing.

Installation of an EV chargepoint
Three years after getting an EV, an 7kW EO EV chargepoint was installed by Everwarm – meaning a window no longer had to be left open overnight with a plug-in 2.5kW EV charger being used.
The subsequently installed solar PV system can only produce a maximum of 4kW, so grid electricity had to be imported if the car was charged during the day, but nighttime cheap rate EV electricity tariffs can be used.

Installation of a smart meter
In 2021 the meter board was found to have woodworm, so Scottish Power fitted a new one for free. Whilst the engineer was on site, he changed the main fuse from 80A to 100A, enabling more electrical systems to be used. The electricity supplier then installed a smart meter. A SMETS2 smart meter is important to have, not only because you get an instantaneous indication of how much electricity and cost you are using, but because it enables many different charging tariffs by the electricity supplier.

Installation of a wood burning stove
A wood burning stove was installed in 2008, with a stainless-steel chimney liner and the chimney then filled with vermiculite.
The stove was a 6kW Hunter Herald with a back boiler, producing a maximum of 3kw to the room and 3 kW to the hot water. This required an air vent to be drilled through the floor for an air supply to the stove.
For several years the house operated on solar thermal or wood stove hot water only, however there were times when no hot water was available to wash!
When the heat pump was later installed, it operates on a mains pressure hot water cylinder, so the back boiler was removed from the stove.

In 2008, we had a solar thermal system installed – 3m2 AES flat panel with polycarbonate cover (which generates an average of 1kWh heat per hour) with Resol controller – this took three days and was fitted by Glendevon Energy.

Stair Curtain
If you have hot air escaping up your stairs to your bedrooms and all your heat is disapearing, a simple solution is to put up a curtain at the foot of your stairs. This holds back to cooler air from upstairs!

Air sealing the house - we looked for every source of draughts in the house. The exposed brick gable ends in the combes were plastered and this reduced draughts in the combes. Care was taken to seal any holes in the building envelope, and areas in the combes were sealed with Pro Clima Intello Plus which is an intelligent hydrosafe airtight vapour control membrane (stops air movement but lets moisture through).

Window frame sealing in 2009.
We found the original double-glazed units had not been well installed, so all surrounds were removed, and insulation gaps made good.
Finally, the surrounds were reattached, and joints sealed. If doing now we would use specialist airtightness products.

Triple glazing was installed in 2022 due to the weather exposure of the house, the old front double-glazing units were still draughty.

Four windows in front, the front door, and the rear cold bathroom window were replaced.

This has made a huge difference to the whole house, with draughts minimised and the house remains quiet even in a storm.

The ADW www.adwscotland.co.uk Rationel FormaPlus aluminium clad wooden frame triple glazed windows and installation cost £16,000, and the installers were careful to fill any insulation voids found and ensure the whole installation was airtight.

A double-glazing unit was added to the lounge porthole to create a triple glazed window.

Warmcell loft insulation was put above the attic ceiling between the joists (do not use it if you ever think you may go into the space again, as when you move it, as it then gets everywhere).
This photo also shows the top of the inter-joist combe insulation, and the air gap maintained to the sarking boards.

The best insulation to use is Thermofleece – this breathes, can regulate moisture and is very pleasant to handle. It is also a very environmental product providing a market for sheep’s wool. However, it is expensive.
 
Hemp, jute, fibreglass, and mineral wool insulation was also tried above the Warmcell, increasing the overall loft insulation to 300mm.

Due to size constraints of the windows, the dormer checks had only 75mm of insulation.

Care was taken to maintain cross-flow to the attic ventilation behind all the insulation and all the combe areas were also insulated with 75mm insultation to create a “warm loft”.

Summary - - 75mm Kingspan between the roof rafters, with 50mm Kingspan across the rafters.
Removing the plasterboard and starting to fit the insulation.

 
Fitting 75mm insulation between the joists

Then 50mm over the joists with all joints taped.

Finally, plasterboard over the insulation and reskim, before painting.

Rigid polystyrene underfloor insulation between the floor joists.
This meant that every piece had to be cut to exact size and then fed through the floor hatch.
If we were doing this again now, we would incorporate an airtightness membrane and use a natural flexible insulation.

Keeping the heat in
From 2005 to 2010, we spent around £10,000 on the following insulation measures:
Blown cavity wall insulation was installed through a utility company scheme.
However, the installation was poor and in subsequent work many insulation voids were found in the cavity – causing cold areas inside.
Where found these were then rectified

We bought the house in Pittenweem, Fife, in 2005 and began by replacing the gas heating system and installing insulation, which improved the building from an estimated EPC E to an EPC D rating. Over the years, we made more and more improvements to finally attain the desired A rating. This included several renewable energy technologies, such as an air source heat pump via larger radiators, a biomass stove, solar PV and electricity storage, an electric vehicle and chargepoint and solar water heating. It also included many energy efficiency improvements, A-rated appliances, draughtproofing, low energy lighting, triple glazing, and a smart meter.