An alternative to Blower Door Testing?

I thought I would write a quick piece on Pulse testing, as I do get asked from time to time about Pulse and whether Pulse is going to eventually replace traditional blower door testing.

Below is a quick Q&A about the current technology.

So what is Pulse exactly?

Pulse is an alternative method of measuring air leakage in dwellings. Instead of installing a blower door fanset into a doorway, pulse is able to test a building without the need for the 10 minute setup. Pulse was developed by Built2Spec which is an EU funded project group.

How does it work?

Pulse works by charging a compressor and releasing a large ‘pulse’ of air very quickly. For those of you familiar with acoustics, it is similar to a reverberation time measurement. For those of you not familiar with acoustics, think of a very large balloon popping (though the pulse doesn’t create a loud noise). The sharp increase and decrease of air can be graphically shown. The steepness of the graph dictates the leakage and along with some clever calculations provides an air leakage of the plot.

What are the positives?

The positives are that:

1.       the actual test can be carried out slightly faster than an existing blower door test. (when fully charged).

2.       The technology is new and exciting.

3.       Results are delivered almost instantly.

What are the negatives?

1.       The kit is heavy. The kit we witnessed weighed about 35kg compared to a standard blower door fan (say a Minneapolis Ductblaster with ancillaries) of about 15Kg.

2.       The kit can be used to test very quickly, but the kit we witnessed took nearly 10 minutes to fully charge, would could only do 2 tests on a single charge.

3.       The test itself may be faster but you still need to set up the test; take temperatures, barometric pressure, calculate the envelope area, temporary seal the ventilation and prepare the building.

4.       The biggest issue, and perhaps the single reason that it will never take off, is that the it cannot do diagnostics. As the kit was first touted to ATTMA as being able to go into existing housing and quickly test with minimal impact to the homeowner, the tester or homeowner will undoubtedly want to know where the leakage points are to put them right. For this you would need to get a blower door fan…

Is it technically ok?

We think so, though we did leave the Pulse demonstrator a list of technical questions that were not answered. Particularly about the pulse being accurate across large distances. We know that blower door fans in large buildings often need to be located in different areas to create a uniform pressure but the demonstrator could not provide us reassurance that the measure being 30cm from the pulse represented the whole room. The last point (we took exception to) was that the demonstrator claimed the test was more accurate and repeatable then a blower door test but the data we were shown gave a +/-14% margin of error compared to the +/-3.5% in blower door testing.

So, will it be useful?

Yes, Pulse will have its uses. Both David McKenna and I were excited about new technology but felt that the lack of diagnostic ability will always get in the way. However, these systems could have uses in fire suppression rooms, fuel cells, containers etc. Places that are hard to reach, need to be air tight and do not always have accessible power.


The kit is new and exciting technology but we feel that it will never replace blower door testing but could enhance it in specific applications. The addition of Pulse to the Building Regulations is unlikely and even so, it is unlikely that millions of pounds of blower door kit from the entire market will be written off.

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