Foreword
Introducing Retrofit
Catrin Maby
West Midlands Citizens
Assembly
September 2023
What is retrofit and why does it matter?
•‘Retrofit’ is a word used to describe making changes to an existing building, about the way the
building uses energy
•This matters because:
•We need energy for heating, hot water, cooking, lighting, electrical appliances
•Buying energy is expensive for households, so using it efficiently is important
•An energy efficient home can be more comfortable, and healthier to live in
•Much of our energy still comes from fossil fuels, causing carbon emissions and climate
change
•We import energy from other countries, and these supply sources are not always secure
•Most UK existing homes are not energy efficient, and we are building new homes slowly
•Our energy standards for new homes are not strict enough to meet carbon targets – so
even homes being built now may need to be retrofitted
What is retrofit in practice?
These are the main things that are currently retrofitted to homes:
•Thermal insulation – to slow down the loss of heat: walls, roof, floor, windows and doors!
•Installing renewable electricity generation – photovoltaic (PV) panels
•New systems for providing heating and hot water, or improvements to existing ones:
•More efficient boilers
•Better heating controls
•Change of heat source, such as:
•replacing a boiler with a heat pump
•installing solar thermal (hot water) panels
Retrofit decisions –things to think about
•The cost of the work – and are there grants or loans to help?
•How much can it save on energy bills – how long will it take to get my money back?
•How much will it save on carbon emissions?
•Will it change how the house looks (inside or outside)?
•Who can do the work?
•Will the work disrupt everyday life while it is being done – noise, dust, mess, need to
redecorate etc?
•What to do first (usually best to do thermal insulation ‘fabric’ first)
•When is the best time to get the work done?
•Does it involve other work (replastering, redecorating, scaffolding)?
•How does it fit in with the life of the household?
Retrofit –when to do it?
Retrofit measures which can generally be done on their own
•Cavity wall insulation
•Loft insulation
•Double glazing
•Low energy lighting
•Insulating pipes and hot water storage tank
•External wall insulation
•Solar panels, new boiler, heat pump
Retrofit measures that involve other work – more disruptive
•Internal wall insulation
•Sloping ceiling insulation
•Underfloor insulation
Retrofit example: 1940s semi
•Loft already insulated
•Double glazed
•Gas central heating
•Single elderly occupant, finds it too cold,
worries about gas bills
Retrofit solution:
•Identified external wall insulation as priority
•Improved comfort
•Reduced length of time heating needs to be on
•Lower bills
Retrofit example: 1970s maisonette
•Only heating was on-peak electric panel heaters,
very expensive to run
•Flat roof leaky
•Home was cold and damp
Retrofit solution:
•Repaired flat roof, which offered opportunity to insulate at same time
•Got cavity walls insulated for whole building at once, including flat downstairs
•Fitted air to air heat pump
•Home now warm and dry
•Painted brick, in a Conservation Area
•250mm loft insulation
•Gas central heating, with efficient condensing
boiler
•Double glazing already installed
Retrofit example: Victorian brick-built semi
•Painted brick, in a Conservation Area
•250mm loft insulation
•Gas central heating, with efficient condensing
boiler
•Double glazing already installed
Retrofit solution:
•External wall insulation to side and rear
•Internal wall insulation to front (where external not allowed as it would
alter appearance)
•Improved comfort – walls feel warmer on inside
Retrofit example: rented stone cottage
•Leaky flat roof, so tenant contacted local
builder
•House quite cold as well as damp
•Builder suggested insulating flat roof at same time
•..and why not loft area too? Landlady said ‘yes’
•Builder then suggested PV too
•Contacted PV company, and arranged for tree trimming
•Builder also put in TRVs and chimney balloon (to raise the
Energy Performance rating to get the Feed in Tariff available at
that time)
•Cold leaky house now warm, dry and generating….