Winter weather highlights the issue of inefficient & cold homes. For some it can be difficult retaining comfortable conditions without breaking the bank, however, cost is not the only issue. Currently, buildings account for 20% of all UK greenhouse gas emissions and as many of these are homes which will still be in use in 2050, when the UK government has committed to ‘net-zero’ emissions. There is a responsibility among Homeowners, Landlords, Housing Associations, Architects and House-Builders to ensure existing homes are vastly improved; alongside new homes operating on low-energy use.
In a previous blog post about Passivhaus standards, we spoke on how we advocate a ‘fabric first’ approach to energy efficient building – high levels of insulation including: high performance windows; airtight building fabric; and ‘thermal bridge free’ construction. While this approach lends itself best to new builds & extensions, there are a number of ways to greatly improve efficiency and comfort in existing homes.
One of the easiest and most effective of these solutions is loft insulation. If you have access to your loft space, there are two basic options:
- Cold Roof – can be a cheap and easy method and is possible to ‘DIY’. It involves fitting insulation between and over loft floor joists. The National Insulation Association recommends adding 270mm for glass wool, 250mm for rock wool or 220 mm for cellulose. (New build properties may have up to 400mm). It may be necessary to add some height to your joists to maintain safe access. This can be done by attaching timber battens or fitting ‘loft legs’. To still use the loft for storage, floor boards can be laid above the insulation – ensure a small gap between the insulation and the legs/battens to allow ventilation and prevent moisture issues occurring.
- Warm Roof – this means insulating between and below the roof ‘rafters’. This is likely more expensive insulation and results in heating a greater volume of your house by including your roof space. But can provide warm, dry storage space. This can be useful if you have pipes or tanks in your loft, as it will help prevent freezing. Care needs to be taken with regard to retaining adequate roof ventilation; we would therefore recommend seeking professional advice.
Moving down the building, next to consider is wall insulation:
- Cavity wall insulation – Cavity walls appeared around 1920 but until the 1990’s, were often built without insulation. To retro-fit insulation: small holes are drilled in the wall exterior & insulation is injected. Insulating cavities is relatively cheap; whilst payback periods vary, The Energy Saving Trust advises on average it could pay for itself in savings after 5 years.
- Solid Wall Insulation – Many traditional properties have solid walls. These can be particularly inefficient and be difficult to insulate. There are two ways to insulate: internally or externally.
- Internal insulation – Is attached to the inner face of the wall – a relatively simple process. Rooms can be done one at a time (no commitment to do the whole house). You can prioritise which rooms would benefit most from reduced heat loss; rooms you plan to redecorate; or insulate as and when budget permits. Please note internal insulation will reduce the floor area of a room and affected walls require redecoration and potentially new skirting’s, door frames etc.
- External insulation – Typically more expensive but minimal disruption within your home. It can also reduce draughts by weatherproofing and filling cracks. May not be appropriate for Listed buildings / those within a Conservation area; and may require Planning Permission. Roof detailing, gutters, window and door openings etc need to be considered. Finishes can vary, but a brick look can be reinstated using brick ‘slips’.
Care is required insulating solid walls to avoid potential issues with ventilation and dampness. Incorrect installation can allow moisture to enter walls, which can damage the building fabric and cause health problems from damp and mould. Using Natural insulation types can improve ‘breath-ability’. We recommend consulting an expert to survey & propose building specific material choices.
For properties with a traditional suspended timber floor, adding insulation is likely possible from either above or below. If floor boards can be removed without damage, insulation can be added between joists and boards re-laid. If an adequate crawl space exists below, insulation can be added from below. Adding an extra layer of insulation under the joists can limit thermal bridging and reduce heat loss further.
Many homes built after 1930 have un-insulated ‘solid’ concrete floors. While these don’t typically lose as much heat as un-insulated suspended floors, efficiency can be improved by insulating above the concrete. This may have a significant impact on your floor levels; with potential issues at door thresholds & steps; therefore installation details must be considered carefully.
Inefficient & Cold homes often warrant insulation paired with draught-proofing. The two combined should make your home feel much warmer, as cold air infiltration is reduced.
Some of the old ideas are still often the best!
This is usually the easiest and cheapest way to improve the thermal comfort of your home. Once you’ve identified areas where draughts are penetrating, simple measures such as placing draught excluders under doors, fixing tape around windows or adding a thermal liner to your curtains, can all make a significant difference to the comfort levels in your home.
While there are many ways to improve insulation and ‘seal’ your home against draughts, it is vital to remember the importance of ventilation to protect against damp and condensation. It is important to strike a balance between insulation and ventilation to avoid moisture problems. Indeed, it would be prudent to get professional advice prior to carrying out any insulation works on your home.
We have the means to eliminate Inefficient & Cold homes, with climate change becoming an ever more pressing driver to act. Adding to, or improving the insulation in your home is an important step in a fabric-first approach to making your house, not only more comfortable, but more energy efficient; and therefore cheaper to run. The variety of passive solutions noted above demonstrates there is an insulation option to suit most properties and budgets. There are also ‘active’ solutions for further energy efficiency. We will be looking into these in more depth in coming posts – so please keep an eye out!