Social Housing Decarbonisation Fund (SHDF) is widely anticipated to be the best grant funding programme for whole-house retrofit projects. So how can one ensure their project is eligible?
Helping pioneer research and innovation to bring the nation’s home to EPC C, 17 local authorities are to be awarded demonstrator funding to help kickstart the programme.
It is important to understand the primary focus the programmes looks upon in a retrofit project in order to align to the requirements. SHDF is most notably led by its ambitious heat demand reduction target, set for the demonstrator programme at 50kwh/m2/year rather than a fuel or carbon target. (Note the main SHDF programme, due for release imminently has relaxed this to 90kwh/m2/yr)
What does this mean for my project?
Due to having a specific thermal target, retrofit projects would need certain measures installed.
Reductions in heat demand are only achievable via fabric performance improvements. Improvements in heat source efficiency or renewables have no impact on heat demand. So it’s purely fabric improvements (including air tightness) comprising cavity and external wall insulation (EWI) and underfloor insulation (UFI), both of which can be expensive and complicated to install within a property. Together with loft/roof insulation and upgrade of windows and doors.
Reaching the 50 kwh/m2/yr target from the demonstrator programme target is unfortunately not feasible for every project as each dwelling offers unique challenges and opportunities. Retrofit projects may still be eligible for other grant funding programmes such as Local Authority Delivery Scheme (LADS), Energy Company Obligation (ECO) Green Home Grants (GHG) and forthcoming Sustainable Warmth programme.
What are the constraints involved with EWI & UFI?
As mentioned previously, fabric performance measures required to meet the target of 50kwh/m2/year can be difficult to deploy and each offer constraints to use within a retrofit project.
External Wall Insulation (EWI)
External wall insulation typically entails attaching an insulation layer to an existing wall before finishing with a protective layer. Externally insulating a wall improves the thermal quality of the building, aids in condensation control, and protects the existing building envelope.
The downside to EWI is it can not be applied to all homes e.g. with technical challenges for historically significant buildings, buildings in a conversation area non-traditional construction.
It is expensive. It costs from £100 to £150 +/m2 plus enabling works, adding significant cost to a retrofit project’s budget.
Due to the typical thickness of the insulation, EWI also has physical constraints. The average thickness of insulation is typically 200mm, introducing physical constraints in areas such as walkways and making coordination of window reveals much more difficult. It is also extremely difficult to fully resolve thermal bridging at party walls, below DPC, balconies, service coordination (gas / electric meters and equipment), and so on.
Underfloor Insulation (UFI)
Just as it sounds, underfloor insulation involves pulling up a pre-existing floor to then lay down a layer of insulation.
This can be extremely disruptive to a dwelling so would only be viable if the property was vacated during the process.
A more innovative approach is the relatively new process of installing UFI is using a Q-Bot robot that is inserted within a floor void which then sprays expanding foam insulation.
The performance offered through UFI is impressive and effective and can provide an excellent (often essential) method of meeting the SHDF eligibility target.
Like EWI, there are physical constraints that can hinder a retrofit project. If the flooring is solid with no void, if the property has beam and block floors or sleeper walls, the installation of UFI is not always possible.
The research modelling VOR has conducted shows that in many cases no amount of other energy-efficient measures can offset an uninsulated floor sufficiently to achieve 50kwh/m2/year. Meaning if UFI isn’t appropriate for the property there is a chance that the retrofit project will not align with SHDF requirements. Perhaps it no coincidence that the main programme is mooted to be operating around a more relaxed target of 90kwh/m2/yr, which is broadly what’s practicable without UFI.
Are there any technology upgrades that can help?
Unfortunately, there is not yet any technology measures that can help meet thermal targets such as the one set out by the SHDF.
In the rare occasion that the property is extremely airtight then MVHR could be an option. This tends not to be an option for nearly all properties so is ruled out.
The term MVHR is an abbreviation for (mechanical ventilation with heat recovery). The waste heat from the extracted air is recovered and used to warm the supply (fresh) air via a heat exchanger.
These help to reduce heat demand, but they come with significant capital and operating cost, as well as complexity and a headache for the landlord in terms of operation and maintenance.
Additionally, if the air permeability is greater than 3 m3/(h m2) at 50Pa, the fan will consume more energy (due to the additional resistance across the heat exchanger) than is saved in recovery heat.
As an example of the idiosyncrasies of energy efficiency, upgrading old inefficient lighting around the property can actually ever so slightly increase heat demand due to the lighting’s contribution to useful heat gains.
Still unsure if your project is SHDF eligible?
Here at VOR, we have a wealth of experience handling retrofit project eligibility for government grant programmes.
We can understand what it takes to devise an effective strategy that will ensure eligibility for SHDF, as well as offering vital advice upon what properties can and can’t work, and alternative strategies.
Contact us today for help with your project needs.
