Paula Morgenstern, UCL Energy Institute
Coming back after Christmas, I discovered mould in my room. Big, ugly spots all around my window and in the outer corners of the room… Yuck! What a setback after a most relaxing break. But what – apart from voluminous lamenting – to do about it?
I settled on an excursion to Wickes, my trusted DIY store, to equip myself for the fight. I turned out not to be the only person declaring war on mould these days: one lonely can of anti-mould paint was awaiting me on the shelf, while Wickes on the whole seemed surprisingly busy. Meanwhile, mould didn’t seem to be the only problem people were facing in light of the current chilly temperatures: Wickes generous offer on convector heaters (Portable – Instant heat – Silent running – Only £16.99) was crossed out red, they had been sold out for days told me the friendly shop assistant. Fan heaters for even longer…
What does this wintery excursion to Wickes tell us about the energy efficiency of our houses? Nothing to encouraging I am afraid.
Landlords often blame tenants for mould growth on behalf of insufficient heating and poor ventilation, but in reality the fabric of a dwelling has an even bigger part to play. Mould needs two things to grow: an organic substance as nutrient (wall paint is often enough) and humidity. In buildings, humidity can – from defect pipes to leaky roofs – have a myriad of causes. One is particularly important because it is present even in well-functioning buildings: condensation. During sleeping for example, people give off roughly one litre of water vapour a night. As long as the air is warm, this is no big problem but when it cools down its capability to hold the water vapour diminishes. This typically happens at outer walls and close to windows. Because the air has a lower temperature there, the water vapour within condensates on the walls/windows. The resulting humidity is enough for mould to grow.
Yet, what does this say about energy efficiency? Well – mould is a serious problem in poorly insulated buildings because a lot of heat is lost through walls and windows. Consequently, the air at these surfaces will be colder than in the room and the event chain ‘vapour condensation – wall humidity – mould growth’ becomes effective. At the same time, poor insulation often means a choice between high heating costs and cold houses as warmth is not retained well inside the building. That is if this even is a choice because sometimes the installed heating systems are not even powerful enough to heat a property to comfortable temperatures. People in poorly insulated houses might have to fight both MOULD (by buying fungicidal wash and anti-mould paint?) and COLD (by buying surplus heaters?).
Not a great situation – neither for the afflicted residents nor for the environment because electric surplus heating is much more resource intensive than primary heating systems. To face the lack of insulation in British homes and to reduce carbon emissions at the same time, the government fully trusts in its Green Deal, a policy permitting loans for efficiency improvements repayable through the achieved energy savings (see here for official information). But a number of concerns have been voiced including whether the Green Deal will reach the people most in need of home improvements and whether upfront assessment fees might put them off. It has also repeatedly been pointed out that the public awareness of the scheme remains low.
My visit to Wickes seems to hint in a similar direction. It suggests both continued inefficiencies in the housing stock and the need for the improved communication of the government’s energy strategy seeking long term efficiency improvement. Meanwhile, nothing in Wickes points out cash incentives now available for home insulation or even the existence of the Green Deal itself. Clearly, without more consumer engagement efforts on behalf of the government electrical heaters will continue to yield Wickes a handsome profit during the next cold spell.