Effectiveness of an HRV in an older leaky home
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Is an HRV effective in an older home with no airsealing? Or would the drafts defeat the system.
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What are you hoping to accomplish?
The drafts don't defeat the HRV, they just make it largely unnecessary because large amounts of fresh air are already flowing in.
There is no benefit to an HRV in a home with an already high ACH number as the home is already ventilated by the leaks.
It also makes an already inefficient home even less efficient as HRV's are not 100% efficient. So you pay for the HRV and then pay every month in increased utilities to operate the HRV and condition the additional outside air.
An HRV is effectively a controlled air leak. The idea behind it is you build a house super airtight to the point where it is not healthy to live in it. Then you ventilate it with an HRV in a controlled fashion to just the right amount to make it healthy.