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Prior to installing an MVHR system I've booked the above in an attempt to get a figure for the current leakiness of our property, discovering where the leaks are, completing temporary sealing on the day to hopefully end up with an improved second figure. This to assist with deciding on whether to continue or not.
in order to get the most out of the visit I'm asking if there is any preparation I can do prior to it happening?
I have gaffer tape and a can of expanding foam filler in readiness otherwise.
We live in a 1970 built bungalow with cavity wall insulation, 300mm insulation in loft complete with double glazed windows and doors not thought to leak but who knows.
Just as a background and following a request from us we had a visit from Deben Climate Centre who were offering a free service to review our property for energy efficency purposes and give advice on what needed doing together with pointers as to what options might be available.
In our case there was very little, thankfully, except that during the time with us, under an hour, they were surprised by how much the CO2 levels had risen suggesting that changes of air were likely low and that we might benefit from installation of a MVHR system to improve air quality and reduce energy consumption hence the above test I have subsequently booked.
Am I barking up the wrong tree or just barking mad?

Adokforme wrote: ↑Sat Mar 29, 2025 12:34 pm Prior to installing an MVHR system I've booked the above in an attempt to get a figure for the current leakiness of our property, discovering where the leaks are, completing temporary sealing on the day to hopefully end up with an improved second figure. This to assist with deciding on whether to continue or not.
in order to get the most out of the visit I'm asking if there is any preparation I can do prior to it happening?

There are often leaks and draughts where services enter the building so how about clearing out the cupboard under the kitchen sink and seeing if a plumber has cut a massively oversized hole for pipework etc.?

This site might give some pointers on where to check:
https://draughtbusters.net/

Thanks @Stig will check it out along with others. Thanks for link too.

I dont think your CO2 experience is reliable for much. It will very much depend on wind strength and direction. Let us know how you get on with the test. Are you an all electric house .

IIRC someone on the previous existance went round all the light fittings on the top floor putting sealant around the area where the wires came from above (I presume the attic which was nt at all sealed - I believe it improved matters but no idea how much.

Thanks chaps,

I dont think your CO2 experience is reliable for much. It will very much depend on wind strength and direction. Let us know how you get on with the test. Are you an all electric house .

Yes, all electric. I take your point about wind strength and direction as I certainly notice a drop in temps during periods of high winds as to other times so hoping the pressure test will at least give us a quantifiable figure to work with. I'm advised that MVHR works well around the 3 ACH @50 Pascals but we shall be lucky to achieve that given property age, construction and my limited attempts at addressing the matter to date.

IIRC someone on the previous existance went round all the light fittings on the top floor putting sealant around the area where the wires came from above (I presume the attic which was nt at all sealed - I believe it improved matters but no idea how much.

Thanks CP, that's a very good point as we've 6 downlighters in each of kitchen and bathroom and I doubt they form any kind of seal with plaster board so well worth some attention there along with remaining light fittings. If I seal the downlighters with silicon I wonder if it would cause problems should I need to replace one at any time in future, or might a simple draught excluder be more appropriate.

Adokforme wrote: ↑Sat Mar 29, 2025 5:31 pm Thanks chaps,

I dont think your CO2 experience is reliable for much. It will very much depend on wind strength and direction. Let us know how you get on with the test. Are you an all electric house .

Yes, all electric. I take your point about wind strength and direction as I certainly notice a drop in temps during periods of high winds as to other times so hoping the pressure test will at least give us a quantifiable figure to work with. I'm advised that MVHR works well around the 3 ACH @50 Pascals but we shall be lucky to achieve that given property age, construction and my limited attempts at addressing the matter to date.

IIRC someone on the previous existance went round all the light fittings on the top floor putting sealant around the area where the wires came from above (I presume the attic which was nt at all sealed - I believe it improved matters but no idea how much.

Thanks CP, that's a very good point as we've 6 downlighters in each of kitchen and bathroom and I doubt they form any kind of seal with plaster board so well worth some attention there along with remaining light fittings. If I seal the downlighters with silicon I wonder if it would cause problems should I need to replace one at any time in future, or might a simple draught excluder be more appropriate.

Beware that down lighters (even LED) can get remarkedly hot and that some include intumessant seals in case of fire. When we installed ours they included a fitting to ensure any insulation above them was kept well enough away to allow a certain degree of cooling. None of ours were fitted through the thermal break however bt all are LED. You can get special hoods and boxes to cover downlighters to ensure the fire resistance and cooling are maintained, I have no idea if they are airtight. I would check with the manufacturer before using silicon sealant - you can get intumesant sealant which might be worth considering.

Adokforme wrote: ↑Sat Mar 29, 2025 5:31 pm Thanks chaps,

I dont think your CO2 experience is reliable for much. It will very much depend on wind strength and direction. Let us know how you get on with the test. Are you an all electric house .

Yes, all electric. I take your point about wind strength and direction as I certainly notice a drop in temps during periods of high winds as to other times so hoping the pressure test will at least give us a quantifiable figure to work with. I'm advised that MVHR works well around the 3 ACH @50 Pascals but we shall be lucky to achieve that given property age, construction and my limited attempts at addressing the matter to date.

IIRC someone on the previous existance went round all the light fittings on the top floor putting sealant around the area where the wires came from above (I presume the attic which was nt at all sealed - I believe it improved matters but no idea how much.

Thanks CP, that's a very good point as we've 6 downlighters in each of kitchen and bathroom and I doubt they form any kind of seal with plaster board so well worth some attention there along with remaining light fittings. If I seal the downlighters with silicon I wonder if it would cause problems should I need to replace one at any time in future, or might a simple draught excluder be more appropriate.

Fire-rated Dow lighters won’t be required for fire-safety if there isn’t habitable space above. However they form a very good seal. I wouldn’t personally chose to apply silicone because they’ll need to be dropped for any testing/inspection.

If it is windy, go round the house with a candle or wax taper to see where the draughts are.
If it is cold, go round with a laser thermometer and see if any doors or windows etc show cold spots where seals or draught proofing is missing.

Thanks guys for further nuggets of information hadn't even realisied there was such a thing as intumescent sealant so duly noted and a tube placed on order. The downlighters are LED's and have hoods above but these don't form a seal.
Being a bungalow they are in the loft with no occupied rooms in question, thanks for the enlightenment Stinsy.