UDCE HOME VISIT

​A report by Dr Jayne Carrick, Postdoctoral Research 

​Associate, South Yorkshire Sustainability Centre on 

​our visit to two local homes in July.

House 1
A detached house, which had solar panels (12, equating to 4.5kW), 2 small domestic wind turbines (1.5kW each) in the back garden, 2 x 3.5kW batteries, and a 16kW Mitsubishi heat pump.
The homeowners undertook extensive retrofitting to improve the energy efficiency of the house when they bought it.

The homeowners undertook extensive retrofitting to improve the energy efficiency of the house when they bought it.

​The batteries cost about £5,500 5 years ago, but they understand they now cost about £900 each. The batteries are located in the garage next to the inverter for the solar.
The heat pump and solar cost around £21,000, which was also completed when they were moving in, to reduce disruption - they replaced an old oil heating system and old radiators. The work took around 5 months to complete. He recommended getting a battery with solar panels, because otherwise they would be 

‘throwing away’ (exporting) 70% of the power to the grid. However, he reflects that the ​​batteries are often full and they often export electricity. They recommend Octopus Energy as they give good deals on the export (PPA). Several of the group recommend NorCroft Energy (Phil Moseley) - for electrical work and solar installation (https://norcroftenergy.co.uk/)
The heat pump was installed in time to receive the RHI payments. The homeowner mentions AIRA - a Swedish company who complete the design
Other group members shared their experiences of looking into and buying heat pumps and one member said he has installed an oversized heat pump to compensate for the lack of insulation (and possibility to install insulation) in his old house
The homeowner did not need planning permission for the 2 wind turbines as they were below the height limit, however, states that he would have needed planning permission for them if they were connected to a heat pump (when they installed them). Some members query this rule and agree to check it.
Asked if they would do anything differently, the homeowner says they would get more solar panels. They were restricted due to lack of space on the roof; however, they are thinking of putting more solar panels on their flat roof, on a framework to position the panels.
The homeowners used Turbine Engineering from Doncaster to install their heat pump, which is on a single phase connection, placed on the garage roof.
One member of the group says they are increasing their solar by 45%, to 14 panels, and have been quoted £2,500 for 1.7kW including the inverter by All Seasons at Halfway, who have been bought out by AIRA.
The homeowner states that their electricity bills are £288/month.
 
House 2
 
Semi detached post war house on an estate in Penistone. The house has external wall insulation with red render and a new porch in yellow and a new blue front door.
 
The home owners explain that they moved into the house in 2014. They understood that the previous owners had lived there since the 1980s and had done little work on the house, so it was quite dated. However, there had been some previous remodelling of the down stairs.
The homeowners did some work before they moved in, including rewiring, replastering, new floor in the kitchen and hallway (tiled) with electric underfloor heating. They commented that they were lucky with the electrician they used as he managed the work, including the plastering, alongside his own.
After they moved in, the homeowners started to identify other big jobs that needed to be done, including the windows and doors as they were getting drafts, mould and damp, the outhouse roof (leaking), and repairs to the house roof. They also wanted to make the house more energy efficient and to align it with the way they wanted to live in it. They expressed a desire to be ‘more green’ but emphasised this was not as part of a vanity project, but to demonstrate how building could be done in accordance with environmental principles.
The homeowners had added solar panels to the roof in 2015 in time to receive FiT payments.
The homeowners used their experience of living in the house to inform the next phase of the work, e.g. the noise, temperature, air quality, light. They employed an architect in 2018 to design the ‘big’ retrofit work, which included drawing up and modelling a range of ideas. Ideas that didn’t make it included a double height greenhouse on the back of the house, which would draw air through the house and into which you could step onto a balcony from the bedroom windows.
 The homeowner commented that the architect is the one area of a retrofit project (of this scale) where he would not recommend people skimp on - the architect on this project cost ‘less than £10,000’.
The design work included having thermal imaging surveys of the house in all weathers to inform computer modelling of different scenarios of energy efficiency measures (e.g. glazing, insulation, porch) to identify the most cost-effective solution (considering the energy savings in each scenario).
The airflow and air quality were major concerns due to the damp and mould problems they experienced in the house and because they were making the house air tight. The greenhouse was dropped from the plans because, according to the models, it wouldn’t draw enough air from the house. 

​To get ventilation they installed a MVHR (mechanical ventilation with heat recovery) system which sucks air out of the house, and into the house from outside, ‘exchanging’ the heat from the warm air from inside to the cold air from outside as they pass. The system works via vents in the ceilings (there are 2 in the kitchen) which is piped up to a unit inside a cupboard in the bathroom. 

The homeowners confirmed that they needed planning permission for the external work and that the biggest ​​obstacle in planning was the design of the porch, particularly the roof.
They moved out of the house to get the work done in 2020. This included: the porch, windows, doors, external wall insulation, replacement floors upstairs, installation of ecowool insulation between the floors, relocation of drainage pipes to run inside the external wall insulation, the MVHR unit and associated infrastructure (including the piping from the vents through the upstairs rooms), new outhouse roof, reconfiguration of two of the bedrooms, repairs to house roof, and loft insulation.
The house still has a gas combi boiler. 

The new windows are triple glazed argon filled K-glass; the homeowners commented that the modelling showed that triple glazing saved significantly more energy than double glazing and was worth the extra money. The frames are wooden, with metal sills to keep water out of the wood fibre insulation. The windows were supplied by the Green Building Store (https://www.weare21degrees.co.uk/), but installed 

​by their builder, which did cause some issues. The homeowners said they would have preferred that the windows opened outwards, but that the supplier advised them that inwards opening is better for insulation. ​The homeowners commented that the porch and new front door had significantly improved the light in the hallway and reduced drafts.

​The external wall insulation is 120mm wood fibre with a lime render which keeps the wood fibre healthy, helping it to breathe. The homeowners commented that the wood fibre insulation is ‘good for cold and hot weather’ but is ‘as horrible to work with as rockwool’ and more expensive. The wall insulation was done by Mike Wye from Devon (https://www.mikewye.co.uk/) who the homeowners recommended.

The homeowners said the MVHR unit has worked well and is like having a dehumidifier with fresh air, keeping the ​​rooms consistently warm but creating no condensation. They did have problems with the noise, but that was associated with the installation and this is sorted now. The MVHR was also supplied by the Green Building Store (https://www.weare21degrees.co.uk/), but was fitted by the builders - their list was too long.
The flat roof on the outhouse was completely replaced. The architect recommended bitumen, but they couldn't find anyone to fit this, however, they weren’t entirely sure why he had recommended it. 

​The homeowners added a Cornish Masonry Stove in the living room and relaid the floor (possibly before the ‘big retrofit’ of 2020). The stove is surrounded by ‘cornish porcelain ceramic’ and weighs 2-3 tons (https://www.cornishmasonrystoves.com/). It is lit once in the morning, burning ‘very hot’ and burning its own gases, the chimney then goes through the surrounding masonry, which stores the heat for the rest of the day. The stove is certified for use in a clean air zone. 
The living room floor is reclaimed Parquet flooring from Parquet-Parquet (https://parquet-parquet.co.uk/).

​The loft was boarded out to give extra storage and the inside of ​the roof insulted with the wool fibre (50mm between the rafters and 2 x 120mm board over the rafters) ‘to bring the loft within the thermal envelope of the rest of the house’. However, the homeowners reported that there is still air flow around the eaves and that there is a noticeable difference in temperature in the loft (compared to the rest of the house.
The homeowners reflected that the builders they had chosen for the 2020 retrofit were not very good ‘for this type of build’, partly because they weren’t on board with the ethos of the build, and that there is a skills gap.

Upper Don Community Energy arrange one home visit per year where we try to visit at least 2 homes in the local area. If you would like to join us next time or have an idea for somewhere to visit, please let us know.