Condensation on a window

Turning up the heat on cold, damp and mouldy homes

Date published: 
27 February 2019

Many Londoners live in homes which are cold and damp. Damp problems affect around six per cent of homes in London with serious condensation being the most common form. 

Vulnerable Londoners are especially at risk from the negative health impacts associated with cold and damp.

During its investigation into cold, damp and mouldy homes, the London Assembly Environment Committee went on a site visit to Thamesmead to see the impact of smart ventilation had made to lives of residents. 


Key findings

  • People need warm dry homes to live in.
  • Homes in London should all be dry and warm however far too many are not. Many Londoners are struggling to cope with damp and mould in their homes.
  • Poorly installed or single measure retrofitting to improve the energy efficiency of homes can worsen damp problems.
  • Ventilation is critical to prevent damp and is becoming more so as homes are built or retrofitted to be more airtight.
  • Energy advice can help residents mitigate condensation in their homes but it must be delivered appropriately, tailored to the living situations and patterns of residents.
  • Social housing providers need more support to invest in improving their current stock, but they also need to commit to better quality energy advice, particularly for fuel poor and vulnerable residents.
  • Private tenants need a clearer route to good quality advice as currently the support they are provided is patchy, depending on the borough they live in.  

What you told us

The Environment Committee on a site visit to Thamesmead

The condition of my home

  • Today much of what is termed damp is caused by lack of adequate ventilation for the water vapour caused by cooking and bathing, but there is also the problem of over-occupation and poor choice of materials together with poor maintenance and bad design.
  • Housing Associations are having to take on the dregs of stock built by speculative developers to minimal space standards and using the cheapest of materials. Most have internal bathrooms and kitchens, tiny windows and are over-occupied so dampness is rife. 
  • The part of the roof that is attached to next door wall has let in rain water a number of times causing dampness in of the bedrooms.  It has been repaired about 4 times… but although the last repair seems to have done the job, the internal water damage hasn't been dealt with.
  • I have double glazing but I think the cold penetrates through the walls. The cost of electricity is very high and I cannot afford to leave the radiators permanently turned on. So I stay in the cold. It's very tough at age 70!
  • I had mushrooms growing on my carpets.
  • Total absence of insulation. No loft space in which insulation can be laid. No cavity walls (1920s terraced construction) into which insulation can be inserted. Flat roof. Hot in the summer, cold in the winter. Central heating supplemented by expensive local electric fires.
  • I live in a two-bedroom council flat and the damp is terrible. I have double glazing windows but that does nothing to keep the heat in. There are days when its colder inside then outside and I keep my kids wrapped in blankets. Heating is too costly and contributes to the mould. My children's bedroom is so damp that mould grows behind the wardrobes. I have to get rid of wardrobes twice due to mould. 
  • My council flat is full of mould. It is terrible. Scaffolding is obstructing the windows, therefore, I cannot open them. During the summer it was unbearable. In the winter the condensation, especially in the bathroom, is terrible.
  • I'm renting and my flat gets about 10C above the outside temperature. No real mould issues as it's that draughty. There are issues inside wardrobes, window frames and bathroom of course but I've lived in rentals with mushrooms growing out of the walls so I'm grateful for that at least!
  • I am in private rented. An oldish house built in the 1950s which has no insulation to the external walls, 20-year-old double glazing which is draughty, plus a few single glazed insulated external doors. Not enough radiators. 

Advice from landlords

  • Without supportive landlords, this problem is very difficult to tackle.
  • I was advised by my housing manager that the problem was due to the numerous plants I had and they told me to get rid. However, the problem continued.
  • The housing association will expect us to have windows and doors open this time of year when it is so cold and damp. Yes I worry about my health and being cold. What is the point of heating a house when we have to have windows and doors open?
  • Our landlord doesn't like to spend much so we have a cheap weak boiler which means that the heating system is never warm enough.
  • Recently my landlord replaced my storage heater with a brilliant but very costly clay-filled radiator with thermostat. Depressingly, it is costing a fortune as my flat will not stay above 21c so it's constantly kicking in (via timer). So I am having to switch it off to save money. My Landlord will not invest unless its proper broken.
  • My partner and I suffered from mould on our last rented flat. We told the landlord and he blamed us. Eventually I forwarded a complaint to the council. They send someone, but the person lacked skill and didn't have any equipment, so the result was very poor. He offered a small passive dehumidifer, that did next to nothing. From my experience, landlords avoid doing repairs. We were forced to live there for three years as we signed an agreement without break clause. He didn't let us surrender. It was incredibly frustrating. The private housing in London is horrible

Hard to heat

  • The apartment is freezing indoors and any form of heating just increases condensation without providing much extra warmth.
  • If I turn off the radiators, within one hour all the heat goes away and it's cold again.
  • My house is freezing - we might as well be sitting in the garden when the heating is not on. The windows are awful and you can feel a draft when they are closed. I pay £118 a month all year round for gas and electric and it is all  going out the window.
  • My daughter has to wear a fleece jacket/long john/thick socks/turtle neck jumper just to keep warm. Her bedroom is damp and very cold in the winter. The council had to put a fan in the bathroom because ceiling kept getting mouldy and black.
  • We have been using dehumidifiers in every room and they have certainly made a difference. We use the cheapest type, small ones bought from discount stores etc… We do try to keep the place warm in the winter, we have no central heating but use two convector electric fires along with two  halogen low energy heaters. We cannot afford to run the larger fires too much, but the halogen heaters are very good. The electricity has cost a lot of money due to the immersion heater that we have to use for our hot water.
  • The house is freezing cold even when sometimes it is warmer outside! If the heat goes off the house takes ages to warm up and also continuous heat keeps the mould at bay better. Our heating bills would be a lot cheaper if the house was properly insulated.

Issues with the windows

  • The single glazed windows provide little to no insulation, meaning condensation is terrible and the window frames mould easily.
  • With single glazing I have a significant condensation problem in winter, which results in black pin mould.
  • The previous owners replaced some of the windows with the earliest and most useless double glazing. We lose heat through them and through the solid brick walls. The result is we spend a lot on gas which is environmentally bad, but we can afford it. We must be typical of a lot of middle/high income elderly people. We aren't the social misery reported by most of the other respondents, but we are an environmental problem.
  • I have experienced damp in the flat I’ve rented for the last nine years. It improved significantly when our landlord put in double glazing and a fan in the bathroom but because of the lack of light. We still have problems with damp and mould on the walls.
  • I privately rent. A month ago the landlords replaced the old windows with double-glazed ones. Winter is here and mould and condensation are back nevertheless. How is it possible? The workers on site already told me these houses were very badly built in the first place. 

Issues with insulation and ventilation

  • After 23 years of complaining, the council decided to insulate the walls and put a vent in the rooms that were affected the most. However, they had to remove the radiators from the walls to do the insulations and replaster the walls and from June, they have failed to replace the radiators.  I am still without heat in my bedroom
  • I did have some damp problems in my flat several years ago, but since we managed to get free cavity wall insulation some years ago, the problem seems not to have returned.
  • I get a lot of condensation on my windows. I find it reduces if I open the curtains before I go to bed. I have to mop up the water every morning throughout the winter. I have small ventilation vents above each window but no opening windows apart from the patio door which is too big to have open during cold weather.

Living with mould

  • We found drying washing inside the home  exacerbates the issue. However in London flats there is often no outdoor space in order to dry washing.
  • Every morning I squeegee the water off the window panes and wipe off the excess water and mould from the window frames. I then leave the windows open for half an hour. Consequently my flat gets very cold. So I wrap up in extra layers. I know I could significantly improve the problem by having the heating on during the day but I cannot afford that. I'm long term sick/disabled and living on ESA but not old enough for a winter fuel allowance. I can't see any solution to this so I just have to live with it.
  • When cooking I have to open the window to the kitchen and the living room to avoid condensation. When I wash my laundry I must dry it inside because there is no other possibility. And this again causes condensation.
  • l am a victim of cold and damp in my flat since 2010. Whenever it is wintertime I don't like to stay in the flat because of the damp and smelly. It's most likely the result of poor maintenance by the landlord with too much crowding making the damp worse. Four adults and one teenager in a flat - and it's horrible. 
  • We have condensation on our single glazed Crittal windows for 4-6 months of the year, even though we ventilate the flat when cooking and showering, and always dry clothes outdoors. Access to outdoor clothes drying space is rare and very important for reducing the humidity levels inside.
  • Double glazing most winter mornings has water running down the panes, even though I keep the window vents open, so it is a daily chore of wiping windows dry.
  • Cheap dehumidifiers from Poundland work a treat in wardrobes.
  • In a ground floor flat we lived in, we couldn't open the windows because we were not at home most of the times. There was no place to dry clothes but indoors. The wall in the bedroom was green. The living room had green spots. We spent time cleaning it many times, but it would always come back.
  • During the winter the only way we cope, as my whole family really feel the cold, is to keep the heating on 24/7 which costs about £70 in gas per month. I use cheap humidifier containers in every room to stop moisture causing mould to grow. I have put tinfoil behind the radiators which helps stop heatloss, but I can't afford to put decent insulation in the loft.


The Mayor should recommend in the London Plan that new housing, especially social and affordable rent properties, has ventilation designed to cope if the home were to become overcrowded.

The Mayor’s retrofit programmes, Warmer Homes and RE:NEW, should ensure ventilation installed through the programmes is sufficient to cope with any level of occupancy. Systems installed should be quiet to avoid residents turning them off, use minimal power and be moisture-responsive.

Social housing providers should review their energy advice strategies and work with residents to offer effective advice on how to prevent condensation, taking into consideration tenant living patterns and household situations, prioritising overcrowded households.

The Mayor should prioritise training and deployment of energy advisors to complement his work on energy efficiency and fuel poverty, under the Energy for Londoners umbrella.

The Mayor should write to the Environment Committee detailing how energy advice services are evaluated during the application assessment process for the Fuel Poverty Support Fund.

The Mayor should develop a guide for private renters and landlords, to help them be more informed about what type of advice they should seek and avenues they could explore.

The Mayor should develop a guide for private renters and landlords to help them be more informed about what type of advice they should seek and avenues they could explore. This should also include information about tenants’ and landlords’ legal responsibilities, for example for the landlord to ensure a home meets the Decent Homes Standard.

The Mayor, the Government and other funders or sponsors should ensure future retrofit programmes are multi-measure with sufficient focus on ventilation. Programmes should account for occupancy levels and the need for heat, ventilation and energy advice as well as insulation, to prevent condensation.

There is a need to unlock funding for retrofit:

  1. As part of the RE:NEW successor programme’s ‘business case’ workstream, the Mayor should present how social housing regulators could encourage London’s housing associations to improve their current stock;
  2. The Mayor should consider allocating funding on the basis of investing in old stock as well as for new builds; and 
  3. The Government should consider increasing the cap for landlord contributions to energy efficiency measures about the current £3,500 (inclusive of VAT) to £5,000.

Any evaluation of the warmer homes private rented sector pilot should assess how well the pilot has reached children, older or disabled people and those in overcrowded homes. A strategy for reaching the most vulnerable residents living in cold and damp homes should be integral to any roll out of the programme and include steps for the Mayor to bring together the GLA, community groups, Citizens Advice and energy companies to support fuel poor households.

The Mayor should write, as Chair of the London Health Board, to Clinical Commissioning Groups to outline the Warmer Homes programme and private rented sector pilot, or any future roll-out, so the information is distributed to GPs to boost referral of vulnerable patients.

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