Damp – a tenants guide to preventing and treating it

We have all been “educated” to never leave windows open both to save energy and to stop break-ins.   Modem life with the complete household being out all day and showers being taken by most people most days does not help.  As I believe that a building to much how people live in real life, I think it is the buildings that need fixing.

I think the Landlord in a HMO should at least fit “continuous mechanical ventilation” in every wet room with an automatic humidity controlled boost.   Some housing departments are now fitting this type of extractor fun in ALL homes when they replace bathrooms, as they reduce the number of damp issues.  Often the ventilation unit is fitted so it can’t be turned off without the use of tools. A “positive input ventilation” unit can easily be fitted in most small homes and will often avoid any issues with condensation.   They are easy to fit as they just go in the loft with one opening needed in the ceiling.  These seem to be a very good quick fix for small homes with condensation issues.

The start of the art for new homes is “Heat recovery ventilations” these units remove the air from all the wet room, using the heat from this extracted air to warm the air that is pushed into all the other rooms.   They work VERY well, but unless the building is sealed to a very high standard, they will not save energy – in a high spec new build these units can save someone like 30% of the heating costs.

We moved into our 1930’s bungalow last winter and had lots of issues with damp.   A lot of trade’s people told us we needed new damp proof courses etc.  I learnt a lot about dump from http://www.dampdecay.co.uk/ and formed the view that we had a bad condensation problem and that I should fix the condensation problem before sorting out any other possible source of damp.

Being a bungalow, with both of us out at work all day, and my wife not feeling safe with any windows open overnight we needed a solution that did not depend on us leaving windows opens.

As our bungalow is large with a complex room layout, on-one could tell me if a “positive input ventilation” unit would work, likewise I did not know if “continuous mechanical ventilation” would be good enough.   My parents have a very early “Heat recovery ventilations” system in their bungalow that solved there ventilation problems.

So we decided to install a “Heat recovery ventilation” unit – so far this winter we have not had any dump or condensation.   Even the mirror in the bathroom remains clear when we shower.   All damp smells have gone.   Even when we come back from being away for a week the home smells fresh.    This is without us having to open windows or vents, the system just looks after it’s self – however the filters do need changing a few times a year.

The “return on investment” with the improvement to our quality of life has been well worth the cost.  As very few local trades people have experience in fitting these units, but they are not that hard to fit, I did all the duct work and fitting myself.     (If I value my time at the rate at get paid as an experienced computer programmer, the cost of my time to do the fitting was still a lot less than what we were quoted for fitting, if I ever have to fix a unit again it will be a lot quicker 2nd time round..)

We brought our unit from http://www.cvcdirect.co.uk , the give very useful advice on choosing a unit etc.   I went for the Itho (http://www.itho.co.uk) unit, their support department was very helpful and did not mind me ringing them with installation questions.   I got most of the ductwork from http://www.bes.co.uk as there prices were about half of what anyone else changed for duct – unlike most plumbing merchants they don’t inflate there “list price” so that they can then give their regular customers a 50% trade discount. 

In a rental property I would be more likely to fit a cheaper system, as having a better quality of air not does lead to more rent, and I don’t have to pay the heating or electric bills.  Also
finding a trade’s person that can fit a “continuous mechanical ventilation” fun in a bathroom
or a “positive input ventilation” unit would also be a lot easier.  

Excellent post Ian, thanks for sharing this 🙂

Very informative post, thanks Ian. We've just (today) had a Nuaire Drimaster PIV system fitted in one of our rentals - an inter-war 3-bed semi with mould problems - so it'll be interesting to see how effective it is. We paid £228 for the unit from http://www.dryhomes.net (owned by a company called Dampco) and haven't yet got the invoice for fitting but the electrician said it'd be between £150 and £200 depending on the amount of cable used, so that's around £400 in total.
(We also had a survey by Envirovent but they quoted about twice as much to supply & fit their system.)

I was very impressed with the designs of Envirovent systems, including how easy
it is to change filters, clean, replace motors etc, but they are very costly
due to the sales system when their franchisee gets a big cut.   Maybe someone can sort out a way for private
landlords to buy direct from them bypassing the franchisee, I know that public landlords
get big discounts from them.   

I did consider fitting 2
or 3 Nuaire Drimaster PIV to our bungalow, but
the quality of air is not that good in our loft as there have been past issues
with mould due to the lack of soffit vents (the first job I did when we moved
in!).   For retrofitting to normal house,
I think the Nuaire Drimaster PIV and/or good bathroom/kitchen fans would be my
first choose.

This is all such good information. I wish I'd seen this post 18 months ago before I paid for the DPC only to find my windows rotting and my computer sitting in a puddle because of condensation issues. Live and learn! Thank you so much for sharing such useful info. Time to book a survey!

We built our own home 2002/3 and alongside massive insulation we installed whole house ventilation and heat recovery. The components cost about £800 at the time and I installed it myself. (FYI 3000 sq ft house/5 beds)

Systems have improved since then and if I did it again I would go for a system that refrigerated the outgoing air (air source heat pump) to heat the house.

We have no problems with damp and have not had to have the system serviced because it is so simple.

I had an Envirovent system fitted in one of my properties last year. Got a big discount for being an NLA member. discount was bigger than membership fee 😉

I am a big fan of Envirovent now, fixed my problem.

The franchisee was a good chap too. He did free surveys on 4 of my properties. Recommended his systems for two and we fitted one to try it out. We will be doing the second

What do you do about cleaning of filters?

(I have images of agents
charging a lot to send a ventilation company in to clean the filters as it is
too complex for them to understand.  I
don’t think I would trust a tenant to remember to change/clean the filters.)

Filters were not mentioned for the unit I purchased, you've got me thinking now

Be interested to hear the outcome if they have to be serviced/ replaced.