Chris2 Posted May 23 Share Posted May 23 Hi We entirely renovated an old house, creating a large new extension. Prior to the work, we noticed that the previous owners had a moths infestation in some old carpet. Even though we did not move in the house, we decided to treat the house with pesticide twice prior to starting the work. The house was then literally fully torn apart, exposed to the elements, new areas being created ect….. As we were finishing the last elements, I discovered , to my horror, that the moths have come back… unsure how and what the larvae are feeding on as we have NOTHING in the house apart from new floors etc….. no soft furnishing, nothing obvious that the larvae could feed on… yet we are seeing some life cycle with small moths and large moths around… We have a MVHR system (mechanical ventilated heating Recovery system) throughout the house, underfloor heating everywhere with screed on floor in the new part and latex on the -1st floor …mix of wooden floor and there will eventually be (manmade) carpet in some areas. I have spoken to many pest control companies, moths experts, who are all saying the same thing, there must be a food source somewhere…. But where? We notice about 15-20 moths in the “In house” mvhr filter everyday - all at different life stages ie small and big moths. They also seem to be more present in the rooms where air is being supplied. Can those pests live in the mvhr system? Anyone has ever had experience of this please? Can you “flush out” the system? Or can we send cameras in the pipes to investigate? Thank you in advance! Chris. Link to comment Share on other sites More sharing options...
Bonner Posted May 23 Share Posted May 23 What do you mean by ‘in house’ MVHR filter? Is that the central unit supply filter? Moths should not be getting through the filters unless they are living and breeding in the heat exchanger matrix! Should be relatively easy to fumigate the system with an insecticide smoke bomb. Link to comment Share on other sites More sharing options...
Chris2 Posted May 23 Author Share Posted May 23 Hi, I have drawned the area of the filter where I am finding live months and being told that they are probably sucked in from the extract air areas (bathrooms etc…)? How would you fumigate the system please? Link to comment Share on other sites More sharing options...
Jilly Posted May 23 Share Posted May 23 Wool moths aren't very big. Link to comment Share on other sites More sharing options...
Mike Posted May 23 Share Posted May 23 11 hours ago, Chris2 said: we have NOTHING in the house apart from new floors etc Except, presumably, clothes? That's where I'd guess they're coming from. Link to comment Share on other sites More sharing options...
Bonner Posted May 23 Share Posted May 23 4 hours ago, Chris2 said: Hi, I have drawned the area of the filter where I am finding live months and being told that they are probably sucked in from the extract air areas (bathrooms etc…)? How would you fumigate the system please? Note, I have used moth smoke bombs before but not with MVHR. If I had the same problem, I would try lighting one near the inlet and let it go through the system on low fan speed (following manufacturer’s instructions of course!) Link to comment Share on other sites More sharing options...
Chris2 Posted May 31 Author Share Posted May 31 On 23/05/2024 at 19:36, Mike said: Except, presumably, clothes? That's where I'd guess they're coming from. Hi Mike, no clothes at all as we have not moved in yet. So absolutely nothing. Link to comment Share on other sites More sharing options...
Chris2 Posted May 31 Author Share Posted May 31 On 23/05/2024 at 14:22, Bonner said: What do you mean by ‘in house’ MVHR filter? Is that the central unit supply filter? Moths should not be getting through the filters unless they are living and breeding in the heat exchanger matrix! Should be relatively easy to fumigate the system with an insecticide smoke bomb. Hi thank you for your reply. They are in the filter of the mvhr. It’s only on one side of the unit which is where the air come in and out from the main house. When you take out the filter it’s on the top side if that make sense. I think that the heat exchange matrix is on the other side? But unsure? Link to comment Share on other sites More sharing options...
G and J Posted May 31 Share Posted May 31 11 minutes ago, Chris2 said: Hi thank you for your reply. They are in the filter of the mvhr. It’s only on one side of the unit which is where the air come in and out from the main house. When you take out the filter it’s on the top side if that make sense. I think that the heat exchange matrix is on the other side? But unsure? As I understand it the filters in MVHR units stop stuff going into your fans. One filters air taken from the house, one filters air sucked in from outside. So if the moths are the house side that means that they are present in the house, and it sounds unlikely to me that they are living in the ducts, merely that they get sucked in as they fly past the vents. Years of dealing with rodents and helping others do the same has taught me that peeps often miss food sources, leading to an ‘oh that?’ moment when they realise the thing they’ve discounted or simply forgotten is the food source, because like the professionals have told you, there always is one. Could there be something between walls or floors? Some wacky natural insulation? Link to comment Share on other sites More sharing options...
Bonner Posted May 31 Share Posted May 31 35 minutes ago, Chris2 said: Hi thank you for your reply. They are in the filter of the mvhr. It’s only on one side of the unit which is where the air come in and out from the main house. When you take out the filter it’s on the top side if that make sense. I think that the heat exchange matrix is on the other side? But unsure? Agree with @G and J, sounds like they are just getting drawn into the ducting, unlikely to be living inside the MVHR Link to comment Share on other sites More sharing options...
Canski Posted May 31 Share Posted May 31 32 minutes ago, G and J said: Could there be something between walls or floors? Some wacky natural insulation? A friend of mine thinks he has rodents eating his modern PIR insulation in a cottage roof that he has renovated. Link to comment Share on other sites More sharing options...
G and J Posted May 31 Share Posted May 31 8 minutes ago, Canski said: A friend of mine thinks he has rodents eating his modern PIR insulation in a cottage roof that he has renovated. Rodents sometimes use inedible stuff for nesting in. I’ve found quite a few wood mice nests in glass fibre loft insulation. But apart from that, there is always a good source, even if it’s only the bait you are putting down to kill em. Link to comment Share on other sites More sharing options...
ToughButterCup Posted May 31 Share Posted May 31 Not sure this is practicable, but I'd consider putting some other wee beastie in there which predates the moth larvae. Once that food source disappears -maybe- beastie will pack its bags and go too? Naaaaaahhh, too simple. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted May 31 Share Posted May 31 11 hours ago, ToughButterCup said: wee beastie in there which predates the moth larvae Like rats? Link to comment Share on other sites More sharing options...
G and J Posted May 31 Share Posted May 31 5 minutes ago, SteamyTea said: Like rats? I don’t know why, she swallowed a fly… Link to comment Share on other sites More sharing options...
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