Heritage Retrofit

BCD SPECIAL REPORT ON

HERITAGE RETROFIT

FIRST ANNUAL EDITION

• then look at generating the remaining

energy needs from renewable sources.

This approach ensures that the ‘low-

hanging fruit’ are chosen first, which

often yields comparable benefits to

more complex, expensive, or harder-to-

implement measures.

In a heritage dwelling, the energy

hierarchy should be considered within

a ‘whole house’ approach – that is,

understanding the home as a system,

and systematically thinking through

whether changes made to some elements

or functions will impact on others. For

example, draught-proofing will decrease

the movement of air in the home, so

consider fitting controlled ventilation.

Chapter 2 of

Warmer Bath

(see Further

Information), ‘Deciding what to do’,

explores how to reduce energy use and

improve energy efficiency in a traditional

dwelling, and compares measures to

each other in terms of cost and carbon

cost-effectiveness. Further guidance on

the appropriate choice of measures will

be available from a forthcoming Historic

England advice note, which CSE has

helped to develop and which will set out

good practice on the sustainable energy

retrofit of traditional dwellings.

EASY WINS

With reference to the above, it is

crucial that retrofit plans start with the

desired outcome, not with a specific

measure. It can be useful to rank desired

outcomes because this can also guide

the best approach. Examples of desired

outcomes are:

• a warmer home

• reduced running costs

• increased market value.

Thinking about a Georgian house with

sizeable windows against this list of desired

outcomes, the measure that might initially

spring to mind could be double glazing.

But the key question is always the same: ‘Is

there something simpler, less invasive, and

more cost-effective that I can do first?’

In this case, there is almost certainly

a cheaper, less invasive way to achieve

all three outcomes. Replacing original

Georgian windows with modern double

glazing is unlikely to have a positive

impact on the market value of the home

in any case, since original features are

so highly prized. It is also unlikely to be

acceptable in heritage terms if the building

is protected in any way. It may be that

timber, slim-line double glazing units

could be acceptable, but these are likely

to be astronomically expensive. However,

a combination of other measures might

achieve the same desired outcomes with

less harm (for example draught-proofing

the original windows, in combination with

fitting thermal blinds and curtains with the

installation of secondary glazing and the

renovation of existing internal shutters).

Ideally, energy-saving measures

should also contribute to conserving

the building’s significance, including

undertaking necessary remedial and

maintenance work, and might even

enhance it by emphasising historic

features and the ways in which they

illustrate the building’s history and use.

CHOOSING APPROPRIATE

MEASURES

Behaviour change is always the cheapest

measure, and should always be considered

first. Better control over heating and

lighting systems can sometimes be

expensive but can reap rewards in the

long run (fitting more efficient boilers,

heating controls and timing systems). The

imminent roll-out of smart meters bridges

the behaviour and control themes, and

‘queue jumping’ is sometimes possible so

householders are encouraged to contact

their utility provider to see whether they

can have a smart meter installed. Daily

interaction with the data from a smart

meter has been shown to alter energy-use

behaviour and cut energy costs without

any other measures being implemented.

Beyond behaviour change and

better controls, we move into the

realms of physical changes to the

home. Breaking down the home into

its constituent elements, the types of

interventions that can be deployed can

be ranked from least to most invasive

(green to red) which, in general terms,

also means least to most expensive.

If all the measures coloured green

in the table on page 11 were deployed

(alongside behaviour change and better

controls), the likely energy savings

and comfort improvements would be

significant. In terms of value for money

they would be likely to cost less in total

than a single red measure in the table.

Detailed guidance on how a range

of measures can interact with each

other can be found in the excellent

Responsible Retrofit Guidance Wheel

produced by the Sustainable Traditional

Buildings Alliance. This allows the

user to select a range of measures

and consider how they might interact

with each other and what the risks to

both the physical fabric and historic

significance of the building might be.

Fuel poverty levels are higher in

traditional homes than in the wider

housing stock, the costs of energy are

rising almost inexorably, national retrofit

policy is seemingly in disarray following

the collapse of the Green Deal, and huge

cuts to local authority budgets mean that

conservation specialists are thin on the

ground. It has never been more important

to ensure that householders have access

to useful guidance on making the right

choices on how to make traditional

buildings more energy efficient.

The UK’s heritage housing stock is an

Produced by the Sustainable Traditional Buildings Alliance, the Responsible Retrofit Guidance Wheel helps

users to evaluate how a range of measures might interact with each other and what risks they could pose to a

given building’s physical fabric and historic significance. (Image: STBA)