To vent or not to vent ..

F

f0zzy

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We have a newish (couple of years) build, heavily insulated house. Problem is it appears to be too well insulated as we seem to have a condensation/damp issue. House was built with trickle vents in the windows.

A builder has advised these are next best thing to useless. Suggestion is to install traditional hole in the wall vents. My experience with these however is not positive, due to heat loss, drafts etc and have heard most people just block these up anyhow.

HRV is one option .. but an expensive one ..

Anyone know of other options ?
 
When we moved into our new house there was heaviness in the air in the living room, it was always warm but it felt damp. It turned out that our chimney was blocked and as soon as it was removed the room had proper air circulation. I’m not sold on making my home airtight. Yes it may make the house warmer and retain more heat but IMO a home needs air circulation to keep the house and its inhabitants healthy. Having said that I still open to convincing.
 
firstly you need a survey from a competent person to confirm the exact cause of the condensation, this would be very important in determining where you go from here.

a solution can then be drawn up that suits all the factors ie cost, existing construction, dwelling type (2 storey?) nuisance threshold, etc

its possible that a passive stack system could be installed into the most effected rooms.

it would be a shame to have a well insulated dwelling peppered with holes.

perhaps the solution could also be to have a strict schedule of 'window opening' times!!
 
theoneill said:
When we moved into our new house there was heaviness in the air in the living room, it was always warm but it felt damp. It turned out that our chimney was blocked and as soon as it was removed the room had proper air circulation. I’m not sold on making my home airtight. Yes it may make the house warmer and retain more heat but IMO a home needs air circulation to keep the house and its inhabitants healthy. Having said that I still open to convincing.
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theres a difference between 'controlled' or 'designed' ventilation and 'uncontrolled' ventilation. An open fire should NOT be considered 'designed' ventilation.....

if there was no air vent in your living room, a pre purchase survey should have clled this up, and the matter should have been dealt with before purchase.
 
Sorry, there was a vent in the living room but it turned out that one of the builders accidentally dropped a bag of cement down our chimney. It's just that the difference in the air quality was amazing
 
theoneill said:
Sorry, there was a vent in the living room but it turned out that one of the builders accidentally dropped a bag of cement down our chimney. It's just that the difference in the air quality was amazing
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:D
sorry for laughing, but thats classic....
 
Thanks for replies. To answer a few points here.

Controlled ventilation. Yes each morning and afternoon windows are opened and house is vented.

We've had qualified plumber on board checking pipes etc for leaks.

We use dehumidifier when condensation/air heaviness is very bad but this
is not a long term solution hence why we have a builder involved now.

Heating is something we're also concerned about and hence we dont want to create a heat problem by fixing the vent issue.

HRS/HRV is an option but its an expensive one which has why I was hoping there is some other technology other than trickle vents that work and dont require blowing a hole in the wall of each room.
 
f0zzy said:
A builder has advised these are next best thing to useless. Suggestion is to install traditional hole in the wall vents. My experience with these however is not positive, due to heat loss, drafts etc and have heard most people just block these up anyhow.

Anyone know of other options ?
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I have vents up high on the walls. There is no heat loss or drafts. Reconsider.
 
aircobra19 said:
Can you explain how that works please.
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sfag is talking rubbish aircobra.

typical wall vents are designed to allow generally 4 air changes every hour.

so picture this, you have a room with a rad and an air vent.
the air is completely changed 4 times every hour in the room by the vent, therefore the radiator has to heat the whol eroom 4 times every hour. thats how it works.

with a heat recovery unit working at say, 75% efficiency, and assuming the same room... then....
the rad heats the room once, during the next hour the HRv system change sthe air 4 times, as like the passive vent, however, every time it changes the air it retains 75% of the heat of the room. therefore with HRV systems the room only needs to be heated once every hour instead of 4 times with a passive vent. thats the principle its based on and the reason they are relatively expensive pieces of machimnery (approx 5k for a standard house)
 
I never heard of them before tbh. I understand that some ventilation is usually a good thing, for chimneys and rooms in general. Then of course you have open vents if you have gas etc. What do you with them?

Incidentally can you get vents for bathrooms, with a electric fan that actually seal when no in use? I've WC which is pretty exposed corner of the house and I think that its a major draught problem. I was thinking of putting a cowl on it, but it there another option?
 
aircobra19 said:
I never heard of them before tbh. I understand that some ventilation is usually a good thing, for chimneys and rooms in general. Then of course you have open vents if you have gas etc. What do you with them?

Incidentally can you get vents for bathrooms, with a electric fan that actually seal when no in use? I've WC which is pretty exposed corner of the house and I think that its a major draught problem. I was thinking of putting a cowl on it, but it there another option?
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aircobra, theres two type of necessary ventilation ... 'background' ventilation that feeds fresh air constantly... and 'purge' or 'rapid' ventilation that allows for fast exhausting of water vapour, smells etc.

both are necessary for health reasons

make sure that any work you carry out complies at least to current building regulations
 
If you only have the problem in one room you may consider the Passivent system.I am not affiliated but am trying it out on a colleagues house.You would need the standard wall vent opening (100mm dia) and then you basically insert the vent you choose from Passivent.The problem with standard wall vents is that they don't always draw air - I think it depends on wind direction.
 
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