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'A' rated house but gaping vent holes



  • Registered Users Posts: 4,864 ✭✭✭ c.p.w.g.w

    Like the light bulbs you have in during the assessment affects your score(well it did when my mother was getting her gaff done)

  • Registered Users Posts: 31,208 ✭✭✭✭ Penn

    Because the vent holes are not related to heat retention, but ventilation. Without adequate ventilation, the humidity of the air within the house keeps increasing, and warmer air can hold greater levels of water content in the air. This then leads to condensation and mould within the house. You need ventilation to provide sufficient air changes.

    That's why it's nonsense to suggest blocking them up or just "open a window every now and again". Air changes need to be constant to keep moisture levels in the air down. Houses nowadays are designed with both heat retention and sufficient ventilation in mind. Changing one affects the other.

    When airtightness tests and BER assessments are done on houses, it's testing the airtightness through the building fabric itself. The wall vents are taped and sealed. The type and number of background ventilation such as wall vents are taken into consideration seperately.

    The assessments aren't just a box ticking exercise, but are used as a design tool pre-construction as much as an analysis post-construction. You can over-specify some elements to compensate for some lower elements, however there's also still minimum specifications things have to achieve to comply with the building regulations (eg. minimum levels of ventilation, minimum airtightness, minimum insulation levels). In some regards, the BER results in some box-ticking, counting etc. But the design and specification first and foremost is done in accordance with achieving building regulations.

  • Registered Users Posts: 2,707 ✭✭✭ MicktheMan

    Correct, it is a box ticking exercise especially when it comes to existing housing and is not (nor was it designed to be) a reliable method of knowing how a house will actually perform with regards to heat loss and indoor air quality.

  • Registered Users Posts: 2,707 ✭✭✭ MicktheMan

    There is sooo much wrong with this post. Please do not heed.

  • Posts: 0 [Deleted User]

    Do not do this under any circumstances. If you've a problem with the ventilation letting in cold, turn on the heat. It's an A rated house after all, it's not going to take long to warm up.

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  • Registered Users Posts: 5,281 ✭✭✭ Chris_5339762

    I'd block them immediately, awful stupidity. But only so long as you ventilate regularly by opening windows and it doesn't hurt to have a dehumidifier too. TBH everyone should get one of those anyway.

  • Registered Users Posts: 2,263 ✭✭✭ Yellow_Fern

    Windows can provide adequate ventilation without any vents. I would for a landlord but for myself its ok. Even if you support vents, there is a optimal size of vents, direction of road noise and prevailing winds to consider. The minimum required air changes required under regulations option for natural ventilation are far too high IMO and local geography is not considered.

  • Registered Users Posts: 31,208 ✭✭✭✭ Penn

    "Far too high" based on what, though? What types of hygrothermal assessments or analysis are you basing that comment on?

    If local geography is determined to be a factor, the onus for that is on the designer to address, and to perhaps look at an MVHR system instead of natural ventilation. It doesn't mean the regs are wrong. And the issue with just opening windows or using a dehumidifier is that they're not always used right by the occupants. Windows are left closed, or dehumidifiers only in one or two rooms or not turned on enough. Hell I've been in plenty of houses where even the trickle vents are left closed by the occupants (who are complaining about condensation and mould at the windows). I've taken high Relative Humidity and Dew Point readings in houses where the occupant is complaining that it's too cold.

    Many owners/occupiers/tenants etc don't understand the need for ventilation or the effects of improper ventilation. They will do whatever's most comfortable or easiest at the time, and the gradual effect of that ends up being mould/condensation which they don't understand because "Sure I'm constantly opening the windows!"

    As houses become more airtight and better insulated, proper ventilation strategies are more important than ever, and can rarely be left just as the owner/occupant's discretion to implement because that's rarely going to be done right. If there's deemed to be an issue with background wall vents due to local geography, then an MVHR system should be installed, and it's the designer's responsibility to establish that.

  • Registered Users Posts: 729 ✭✭✭ SupplyandDemandZone

    We just blocked ours up as the house was an ice box with them left open. We leave the vents on the windows open and we've no condensation. Might not work for everyone

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    How could house be A rated with uncontrolled passive vents in the walls. It wouldn't pass an air tightness test.

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  • Registered Users Posts: 31,208 ✭✭✭✭ Penn

    Wall vents are sealed and taped during the airtightness test. The airtightness test is testing air permeability through the building fabric itself (walls, wall/ceiling joints, wall/floor joints etc).

    Anywhere that air is supposed to escape from (wall vents, opes) is sealed so as not to affect the results.

    TGD Part F:

    Air infiltration: The exchange of air between outside a building and inside other than through openings provided by design (for ventilation, access and other purposes). Infiltration is caused by pressure difference effects of wind and/or stack effect and occurs through cracks, porosity of building elements and other unintentional openings in the building fabric. 

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    I'd love to see the SEAI do another study to see how many houses are actually built to the standard they claim to be. There is almost no checking of how houses are built.

    If you are self building you have to have eyes in the back of your head trying get tradesman and builders to do things to properly. I can only imagine what happens everywhere else.

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

  • Registered Users Posts: 31,208 ✭✭✭✭ Penn

    But what are you testing in that case? You can't test the air permeability in the room with a wall vent open.

    The airtightness test is required to determine the air permeability of the building fabric. It's seperate from how much ventilation is provided to achieve the required level of ventilation/air changes per hour, and there are different ways to achieve that (eg. wall vents, wall vents + trickle vents in windows, mechanical ventilation, mechanical ventilation & heat recovery).

    One feeds the other. For example if you want to use an MVHR system, you need a better airtightness result because otherwise you're going to be losing too much through the building fabric and the MVHR system won't be able to operate efficiently.

    But again, airtightness testing is measuring unintentional air infliltration through the building fabric. Background ventilation (wall vents, trickle vents) are sources of intentional air infiltration to provide the required air changes.

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    You are measuring the positive air pressure (or negative). Once you uncover the vents all your measurements are null and void. ( I get the fabric of the house has been tested). But if house was in an exposed location (in relation to the wind) vs sheltered location the pressure of air coming through the vents, would be entirely different vs the test. You could have a gale coming through those vents.

  • Registered Users Posts: 31,208 ✭✭✭✭ Penn

    The external louvres on most wall vents dissipate the effects of most strong gales. But yes, again a lot of that comes down to the designer and if they feel the external air or noise levels will be factors, alternatives to wall vents should be assessed.

    But that's not an excuse to block up wall vents and just say "I'll open the window every now and again." That's the issue, and I've seen it in plenty of houses where it leads to mould & condensation because the required level of air changes aren't being achieved.

  • Subscribers Posts: 37,764 ✭✭✭✭ sydthebeat

  • Subscribers Posts: 37,764 ✭✭✭✭ sydthebeat

    another ignorant statement.

    dont post when you havent a clue

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    Not an excuse no. Can also be a safety issue depending on the heating in the room.

    But if people are doing things like that, or struggling with draughts it shows there's a problem with vents like this. Its too simplistic to dismiss it out of hand.

  • Registered Users Posts: 486 ✭✭ Bargain_Hound

    I have often thought the same (Based on my experience). Having previously owned a new build A3 rated home, I no longer have any confidence in the rating system actually meaning anything. It was no warmer then the current B3 15+ year old house we live in now. Nearly every skirting board had a draught coming in under it, air coming in around the front door and making its way under the skirting again, and the French doors into back garden were never fitted correctly either, again a visible hole at the bottom of the door frame to the outside with air leaking. And that was just what I uncovered. Corners were definitely cut and I'm sure behind the plasterboard/brickwork there were many shortcuts taken.

    Oh, each room had 4" vents and they let in an awful draft along side road noise.

    Our new (old) house is nearly just as bad, but at least I didn't buy this on the premise of it being super efficient (A3+) and built to a high standard.

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  • Subscribers Posts: 37,764 ✭✭✭✭ sydthebeat

    the BER system is absolutely NOT a measurement of the build quality of a structure.

    nor does it measure air infiltration.

    Air infiltration is measured as part of Part F compliance, through an air tightness test.

    If there is an air tightness test result, it can be included in the BER assessment, if theres none, then a default value is applied.

    the BER system is used to compare like with like properties... nothing more, no matter how SEAI sell it.

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    Obviously windows and doors and construction techniques and materials are better. So there will be some improvement in a new build, for those reasons. But if its been built badly it will be compromised.

  • Moderators, Regional North West Moderators Posts: 43,867 Mod ✭✭✭✭ muffler

    I see there are plenty of trolls and bar stool experts in the forum these days.

  • Posts: 0 [Deleted User]

    I've a 6" vent in every room. Front of the house (red brick) I've triple airbricks in front of each vent. Elsewhere, there's a circular vent cover. They may as well not be there, louvres do feck all.

  • Registered Users Posts: 886 ✭✭✭ oinkely

    We have mid 80s semi d and there were no vents in any of the rooms when we bought it. I have since added one to the small box room to help with condensation etc. I got acoustic vents which have a foam lining and baffles to minimise the ingress of noise and light and they work well. Condensation is reduced and while there is an increase in the noise you can hear from outside it is not too bad, considering the large hole that has been added to the wall. Definitely better than the standard hole with a bit of piping in it and a louvre on each end that is in the kitchen extension. I will get around to adding the same vent to the rest of the bedrooms at some stage and also replacing the current kitchen vent with the acoustic version to reduce the noise. Worth looking at these as an option rather than filling the hole. In the mean time its windows cracked in the non ventilated rooms when sleeping.

  • Registered Users Posts: 7,531 ✭✭✭ Flinty997

    Always wondered why they don't have cowls or simple baffles to stop direct airflow.

  • Administrators, Computer Games Moderators, Sports Moderators Posts: 31,394 Admin ✭✭✭✭✭ Mickeroo

    Have you a link to those acoustic vents you used?

  • Registered Users Posts: 2,263 ✭✭✭ Yellow_Fern

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  • Registered Users Posts: 822 ✭✭✭ silver_sky

    Interesting thread. I've a 2021 A2-rated build and it's got these open sliding vents. Some rooms don't hold the heat so well - especially the living room where you can feel the cold air right at the back of your neck due to the positioning of the vent and room layout.

    The builders did go about putting a ventilation system (Vent Axia Multivent) for the bathrooms though. It sits in the attic and pipes up to it.

    I've been looking at single room ventilation with heat recovery to replace the existing open holes but not sure if this is the right way to go about it. Heating is gas but looking to change to heat pump in the next few years.