Thermal performance of park homes, mobile homes and static caravans
Building regulations do not apply to mobile homes, park homes and static caravans and instead these are subject to thermal performance requirements. This blog post explains what the rules and regulations are.
Park Homes can be difficult to heat, as they typically have thin, single skin walls, and cannot easily be insulated to the same level as traditionally constructed dwellings. Whilst modern versions can be relatively well insulated, with double glazing and energy-efficient boilers, the majority are more likely to be older and built to minimum standards.
Static Caravans for use as ‘Summer holiday accommodation’ only.
Most static caravans are built to BS EN 1647, which does not have quite the same insulation requirements as BS 3632. A holiday home built to this standard is only recommended for summer use as temporary or seasonal accommodation and is not suitable as a permanent residence.
BS3632 sets insulation levels that supposedly ensure that Park Homes are “built and insulated to a standard that will mean they are comfortable for use all year round”, but in reality residents of Park Homes tend to have a higher than average incidence of fuel poverty, with high fuel costs and comparatively poor energy efficiency.
The current provisions for insulation and thermal performance standards in BS3632 are significantly below that set by current building regulations.
The external walls, floor and roof, excluding any door and window openings, are required to be constructed and finished such that the U-value does not exceed:
- 0.5 W/(m2K) for the wall and floor construction; and
- 0.3 W/(m2K) for the roof; with
- Windows and doors with a maximum U-value of 2.0.
It is permissible for a wall, floor or roof to have a higher U-value than the values specified provided the average U-value is achieved. No individual U-value should exceed 0.6 W/(m2K).
It is estimated that there are around 71,000 park homes in occupation; even if all of them were built to either of the above standards, they would be costly to heat and their occupants likely living in fuel poverty. It is however much more likely, that many older homes do not even meet these standards.
Is there a better standard to come?
BS3632 is currently being reviewed via the British Standards Institute; the insulation levels proposed for new units following a revision are for the external walls, floor and roof, excluding any door and window openings, to have average thermal transmittances (U values) of not greater than:
- 0.35 W/m²K for the walls;
- 0.35 W/m²K for the floor; and
- 0.2 W/m²K for the roof.
- Windows and doors with a a U value not greater than 1.6 W/m²K (complete doors and windows including frames).
Upgrading those already in existence
There isn’t a retrofit standard for Park Homes at this time and as it stands, securing finance to improve them can be difficult.
Park homes don’t need an Energy Performance Certificate (EPC) for re-sale or rental purposes, but one can be lodged in England & Wales for ECO and Green Deal purposes, providing it’s produced in accordance with BRE’s updated guidance document. So there is potentially scope for securing finance providing a payback can be shown.
Existing energy efficiency performance of such properties is often very poor and with limited fuel types available on sites, bottled gas is the typical means of heating most Park Homes; the associated costs and carbon emissions from such heating measures is usually high. A combination of high heating demand and high heating costs results often in an associated high likelihood of occupants living in fuel poverty.
Currently, the cheapest, most effective and preferred method of improving the energy efficiency of a park home, is to put external cladding on it. This can dramatically increase insulation levels, and significantly reduce the heat demand of such dwellings, providing significant cost savings for occupiers and it can be relatively cheap and easy to install. There is also a potential for improving the fire performance of the structure when cladding.
Whilst external cladding will modestly increase the external dimensions, there is guidance from CLG to state that this comparatively modest increase in dimensions will not usually have any significant impact on sites overall, so there is definitely scope (with a site owner’s permission) for these works to be undertaken and doing so can drastically improve the standard of living for the occupants giving financial and health benefits alongside the environmental ones.
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