Prevent heat loss in your home

Prevent heat loss in your home

Houses will always lose heat. The colder the outside temperature or the stronger the wind, the greater the amount of heat lost through the walls, windows, doors and roof of your home (‘the building fabric').

In general terms an older building will lose proportionately more heat than one built more recently. Over the past 20 years successive versions of Building Regulations have required increasing amounts of insulation and air tightness thus reducing heat loss through the building fabric and through draughts.

If you live in a terraced house a higher proportion of heat will be lost through the floor and roof as you will lose almost no heat through the party walls – assuming your neighbours also have their heating switched on. If you live in a flat - that’s not on a ground or top floor - almost all the heat lost will be through the outside walls. 

Preventing heat loss

This illustration shows where your home’s heat is being lost.  Source: 

Steps you can take to prevent heat loss

We suggest you start with the easiest and cheapest problems. It can be easy to find and fix gaps around windows whereas fitting external wall insulation could be disruptive, costly and, if you are in a conservation area or your building is listed, you will require planning permission.

Fix the draughts

People are very sensitive to air movement – even if a draught has the same air temperature as the rest of the room it will have a cooling effect on your skin and make you feel uncomfortable. Unfortunately, the temperature of most draughts is that of the outside air.

Insulate roof spaces

The latest Building Regulations require 300mm (about a foot) of loft insulation. Loft insulation is an effective way of reducing heat loss. You should make sure that the insulation reaches right into the eaves so you don’t have cold spots on the ceiling beneath.

However, unless your roof has separate roof/ridge ventilation you will need to create a gap between the top of the insulation and the bottom of the lining ‘felt’ to make sure that some fresh air is able to circulate in the loft.

Improve the floor

If your house has a solid floor you could use a thick carpet underlay. Older properties should use a permeable (breathable) underlay to allow any moisture in the floor to escape.

If your home has a suspended timber floor, draughts might be the main problem. If so, you should check that the underfloor ventilators are clear and unblocked. If they are then you can use a thick underlay to reduce the amount of air coming through the floorboards and to provide some degree of insulation.

Thermal imaging

The best way to see where heat is escaping from a building, through the building fabric and by draughts is to use a thermal imaging camera at ground level. Thermal images taken from both the outside and inside of a building will show you where most of your heat is being lost from. This will help you decide what to fix and how best to fix it.

Heat loss in a house

In this thermal image taken from the outside of the property you will be looking for warmer areas (red hot, blue cold) to identify where heat is escaping. Source:

Heat loss in a kitchen

In this thermal image taken from inside the property you will be looking for cooler areas to identify where the cold from outside is entering the room. Source:

Improving energy savings

There are a range of opportunities to improve your energy savings and how to insulate your property. For information and further advice that may help you to make an informed decision about managing the energy efficiency of your home, visit the Energy Saving Trust website

Last updated: 11 March 2020