A Retrofit Case Study: Upgrading an ‘F’ rated home to an ‘A’
Number 23, a 1960’s dwelling, has undergone a ‘whole house’ retrofit and upgrade. The home’s ‘F’ Rated EPC has been upgraded to a ‘C’ and shortly to achieve an ‘A’. As a result, its energy efficiency is improved and its reliance on fossil fuels for both heating and energy is reduced. Improving Indoor Air Quality (IAQ) of the building is an integral part of Number 23’s retrofit by reducing VOC’s (Volatile Organic Compounds)
In 2014, Number 23 was a ‘Hard to heat, hard to treat’ 3bed dwelling. Typical for the age of the property, the home was heated with oil-fired central heating, had uninsulated walls and floors with minimal roof insulation. Condensation was present between the double glazed panes and the only hot water source was provided by an uninsulated immersion heater. No extraction fans were installed in either of the two bathrooms nor kitchen.
Unsurprisingly, the EPC was an ‘F’ with a SAP Rating of 36.
Phase 1
On completing Phase 1 of the retrofit, a full SAP calculation upgraded the EPC to a ‘C’ with a SAP Rating of 76, a 42point improvement.
Retrofit works included;
- Removal of the oil-fired central heating system,
- 4no. storage radiators and a 5KW rated eco-design ready multi-fuel wood-burner.
- 13no. triple glazed windows installed
- 50mm PIR insulation boards and plaster-boarded to the inside of the external walls
- A standard Direct 250Litre, unvented and insulated immersion heater installed
- 4.7KW of roof mounted PV’s
- Complete re-wiring
- All plumbing replaced
- All walls and ceilings replastered
- Solid oak floor boards throughout https://www.diy.com
- Redecorating throughout https://www.brewers.co.uk
Phase 2
As the retrofit final phase works near completion, an upgraded EPC is expected to achieve an ‘A’, adding a 22points to attain a 92 rating.
Phase 2 retrofit works include;
- 50mm external wall insulation and silicone render system https://ewipro.com
- Five additional triple glazed windows and doors https://www.vincowindows.co.uk
- Composite front door https://www.vincowindows.co.uk
- Roof voids filled with quilt insulation
- Between 230mm and 1.2metres of extruded polystyrene to the underside of the floor
- A Tesla Powerwall 13.7KWhr battery https://www.tesla.com/powerwall
- Passive stack vents are installed to the bathroom, ensuite and kitchen
Building Performance Monitoring
Recently, sensors have been installed, recording in-use building performance with an emphasis on Indoor Air Quality (IAQ) together with temperature, relative humidity and EV charging.
Those sensors include;
- Internal and external air temperature
- Inside and outside Relative Humidity
- Internal Barometric Pressure
- Internal CO2 and HCHO (Formaldyhyde)
- Indoor Air Quality (IAQ)
- EV Charging
- PPM 2.5 and PMM 10