Improve Energy Efficiency

Doing it in the right order

Most of us don't live in recent, energy efficient homes. We need to add (or retrofit) energy-saving measures. Plan a series of steps, which can be implemented over time, saving money and disruption.

Below is a summary of measures to consider taking in your own home.

You can find more information in our Energy Efficient Homes Information Sheets.

"Fabric First"

Improve insulation, air-tightness and ventilation:
- Window and door replacement.
- Loft insulation
- Wall insulation - cavity, internal and/or external
- Floor insulation
- Air tightness
It's vital to ensure that you address any damp problems and that you have appropriate ventilation and moisture control to avoid subsequent issues with damp and mould. Options include: trickle vents, extractor fans, and mechanical ventilation and heat recovery (MVHR)

First retrofit priorities

Draughts.
Drainage - maintain gutters, downpipes and drains.
Condensation and damp - see above.
Asbestos - may be discovered during a retrofit and likely to require specialist removal or treatment.

Take opportunities to insulate

You can insulate your loft at any time, although it's more comfortable up there in the spring or autumn.

But adding wall, loft or floor insulation is more disruptive. Plan to do it when opportunities arise, possibly a room at a time, over a number of years.

You could fit internal wall insulation when you are:

Installing a new kitchen or bathroom
Replacing or repairing plaster or plasterboard
Or just emptying and decorating a room

Fit external wall insulation if you need scaffolding, which is a significant cost, for any reason:

Working on rendering or painting
Fitting replacement windows

Windows & doors

Replacing single-glazed windows, with modern double- or triple-glazing, and old draughty doors makes a home feel far more comfortable and significantly reduces energy losses. It's important to avoid thermal bridging around the frames.

The reduction in energy use, at current prices, means that replacement double-glazed windows typical pay for themselves over 15 to 20 years.

Loft & roof
insulation

Adding loft insulation is usually the most cost-effective way of reducing the energy lost from a house. If you have none, adding 300mm of loft insulation will typically pay for itself in one to two years. There are few better investments.
Care is required if you have a 'room in the roof', have ceilings immediately under a flat or sloping roof, or have dormers. Insulation needs to be installed to avoid condensation, either by having a moisture-proof membrane on the warm side of the insulation or, in certain older properties, using a fully-breathable structure.
Make sure that any air leaks into the loft space are blocked. For example, this could be from behind plaster board in the top-floor rooms or through downlighters.

Wall insulation

It's almost always worth fitting internal or external cavity wall insulation to houses that have solid walls (without a cavity), as the work has a short payback period, typically of a few years. Care has to be taken to manage damp. In particular, condensation can form if a waterproof layer is installed on the cold side of any insulation. Some of the issues to consider are covered in this video:

Returns are also good for adding cavity wall insulation to houses that have cavity walls but no insulation in the cavity.

It can be worth adding internal or external wall insulation to houses with cavity wall insulation, built up to about 2002 (to 2006), when the building regulations standards were tightened.

Houses built since then should have reasonable wall insulation, and it's currently not likely to be worth improving on this.

Floor
insulation

The ease with which you can insulated a suspended timber floor varies depending on access:
- If you have access, insulation can be hung between the joists, suspended on net fastened to the bottom of the joists.
- Without access, you need to lift the floorboards, which is usually a big job.
Concrete slab floors are, obviously, hard to insulate. You need to lay a layer of insulation with a floating timber sheet floor on top of it. All skirting has to be removed first, and doorways and the bottom of steps dealt with.